It seems that worn out carbon brushes causing faults in the 729's is a good indicator that more frequent PM's are needed. Worn out belts also.

Grant Saviers

Brenda,

There’s a status white board mounted on the side of the Liebert unit.
But we’ve haven’t been disciplined at keeping it up to date. :(

There are also record books for each of the 1401 systems and subsystems, but over time the team slowed in their use. :(
It would be good to dust them off. :)

I have encouraged the team to use and update them.
Any effort to keep them updated would be welcome and desirable encouragement/kick-in-the-pants. :)

Best Regards,

— Robert

p.s. Flashlights are always appreciated. :)
I believe there’s an LCR meter in the workshop. There’s definitely one or more capacitance meters

Steve Madsen and I gave the demo. We had four(4) people at the start and twelve (12) by the end. The sorter was not working so we skipped it. We used CT for the demo and all (mostly) worked well.

Notes:

1. When I came into the room at 10:00 AM the light on top of CT was on and thus the CT circuit breaker was on.

2. The Green Bar paper on the CT had been replaced by 1/3 full box of old plain White paper. Since the paper was old, we had the paper separate during the demo Big Print. This gave us the opportunity to demonstrate replacing paper on the 1403 during the demo. Moral: If there is not new Green Bar loaded into the printer before the demo, change it before the demo.

3. Arthur Morgan, one of the people training to be a 1401 Demo Operator, donated his father's IBM THINK sign for permanent display on the CT 1401. Photo attached.
   

Iggy

> From memory, and I was working in the 60’s, on 2401’s, very similar to 729’s, it was once a week.
>I think PM once a month would be recommended.

I relish and look forward to regular 729 PM (per your checklist below)!
I’m also wondering about the best PM interval, based on our lower up time/utilization compared to original usage.

From your 1960s memories/experience, were the 2401s generally running around the clock, 24/7?
(As were our 1401s during their first ten years of 24/7 service at insurance firms.)

Any one of our 729s only runs about 14 hours a week (or less), for a utilization of just 14/168 = 8.3%, that implies a scaled-PM interval of 1/0.083 = 12 weeks = 3 months.
Or perhaps lack of 24/7 use (and frequent power cycling) accelerates the need for 729 PM?
Perhaps some 729 PM items make sense once a week, and others less often?

- Robert

From memory, and I was working in the 60’s, on 2401’s, very similar to 729’s, it was once a week.

In our case, the machines are so old, that materials and contact surfaces deteriorate much faster.

If we want to keep all these 729’s in good running condition, and able to run from CPU programs, I think PM once a month would be recommended.

Iggy

Brenda,
Thanks for taking on 729 PM!
(It’s only really been done when Iggy was in or a 729 was acting up...)

Thanks for all your help, expertise, and contributions! :))

— Robert
p.s. Iggy has said he’ll try to get back in a couple of months or so...

Hi All,

(Iggy, thank you finding the cryptic location for that test bus. : )

In general, I fancy the idea of doing preventative maintenance, whenever time constraints permit.
In the head assembly section, it's stated that the heads should be cleaned every 8 hours of service or 10 reel passes.
I would also like to clean the inside of the tape area, when time permits.
It would seem that shutting the drive doors, nightly would help.

Interestingly, there is a routine 48v voltage check.

This following is from one of the (223-6988_729_CE_Mar62.pdf) 729MKII Manuals:

Take Care,
Brenda

On Wednesday Bill Worthington and I gave the demo to 28 guests and mini-demos to 15 more before and after the main demo, including 8 from a senior group after their Restoration tour. Several visitors were from the Hamburg area of Germany. Like most German visitors, they enjoyed reading the labels inside the DE 1403 and hearing about the other working 1401 in Boblingen.

We started the demo on CT, which failed in the mode it has often shown recently. After power on at about 1:00 pm, it loaded BigPrint and read name cards fine for about two hours before the demo, but refused to load BigPrint during the demo. We made a hasty switch to DE (thanks Bill for moving our stuff), which ran programs fine.

We returned to CT to run the tapes via the TAU. All four drives were loaded with about 1/4 of the reels read. Newly repaired Drive #1 just stopped reading at one point. Pressing Start caused it to resume spinning. Drive #2, which often displays a multisecond pause before executing a rewind, refused to go into fast rewind at all. Drives #3 & #4 ran fine.

The 026's and 001 worked well. The 083 sorter was inoperable, per the Restoration team.

At about 4:30 after the demo and late visitors, we shut down all systems and power and left the room open with the video playing, the standard practice. Everything was locked and all power was off, verified by no "pilot" lights lit on the two CPUs and the unit record gear.

Two students from the demonstrator class were present and got to witness the real-time CPU switch and other recovery actions we sometimes need to take.

Pat

from Stan Paddock, DE 1402 punch switch - dated Nov 1, 2022 1:27 PM

German Card Punch: A UPS truck stopped by my house yesterday. He had a small package for me from Greece. This is a new micro-switch for the punch in the German system. Brenda will be installing it in the German system tomorrow. Stan

from Ken Shirriff, 729 tape update - Nov 2, 3:45 PM

Summary: DE tape drive #1 has a problem with the -48V circuit breaker tripping. Details: Iggy said that there was a power supply problem. The symptoms were that the tape drive was completely dead except for the unit number light. Brenda measured the voltages to the SMS cards: +6, -6, +12, -12 were all okay. At the circuit breakers, the voltages were okay except the +62V was very low, around 26V, and the -48V was dead. (The separate -48SP supply for logic was okay.) More investigation showed that the -48V breaker trips when you turn the drive on. We measured at the power supply and the -48V was good (about -53V). We suspect there is a short somewhere that is tripping the breaker. Frank suggested that the circuit breaker itself might be bad. Next week, we can remove the circuit breaker and check it on the bench. If there's a short, it may be tricky to track it down. The -48V is distributed by TB 130-COM, a 13-pin terminal block. We could remove connections from the terminal block to narrow down the location of a short, except we can't find that terminal block. We found many other terminal blocks, but not the -48V distribution. Any ideas where it is? Ken

from Ignacio Menendez, 729 tape update - Nov 2, 4:03 PM

Ken, just before leaving I found a location shown on page 09.04.2, Brenda was still there and I showed her the location shown, in the relay gate. Iggy

from Ken Shirriff, 729 tape update - Nov 2, 4:25 PM

Great! For reference, here's the diagram from 00.04.2: Here's a file photo of those components. The terminal blocks must be on the back:

from Ignacio Menendez, Tape Drive's Status - Nov 2, 4:28 PM

Connecticut tapes: PM’d all 4 drives. Drive 4 was dropping ready in go-reverse, pulling tape out of the right column… adjusted right shaft reverse clutch carbon contact assembly, repositioned it closer, and replaced a holding screw, which would not tighten correctly. Ran from TAU fwd/reverse, all 4 drives OK. R/W only drives 1 & 2 are OK; 3&4 need some looking into. Drive 3 needs ALL 4 motor to clutch belts replaced, have old style ‘cog’, but we have in stock ‘V’ belts, which are OK… will run for a while, but need replacing. German tapes Tape 1, see Ken’s report, power problem Tape 2 was missing idler shaft retaining wire…. Made one with a piece of solid, but small diameter wire, works OK. Drives 2&3 OK for go-fwd/bkwd. These 2 drives intermittently detect end of tape at the same time, and light up the indicator on the top panel; no end of tape sticker on either one…. Need to investigate further. Had a few errors R/W, but may be the tapes, or a need for adjustments. All 7 drives appear to be at a point that the carbon brushes need to be replaced… Last time, some 5 years ago, Mark made some for us in his lab. Dave Bennett found a shop nearby that made many of these, perhaps he can get some more made up. Iggy PS… It was an honor and a pleasure, as always, working with you guys.

from Ignacio Menendez, 729 Preventative Maintenance Checklist - Nov 2, 4:54 PM

Robert asked Iggy for a checklist for our tape drives PM... (Perhaps go through these about once every 4 months?) Robert, you asked me about what quick checks can be done: With all power off to each or all drives: ->>>(It is very easy to get a bad electric shock, if power is present!)-<<<< make sure all vacuum ports at the bottom of both columns are free from debris, like pieces of tape. the capstans should be able to retract, when manually extended, with little or no effort… if not, try adding a drop of oil on the shaft itself, front and back. The idlers on the prolays, should not bind, and rotate freely… if not, the shaft needs to be removed, cleaned and a very small amount of oil applied… then reassemble, making sure the retaining small wire is inserted on the shaft and screwed down. the sense Micro switches should transfer when the flywheels on the rear fwd and back, and not in physical contact. If not, need adjustment. if equipped with an eddy current mercury switch on the back of right shaft, should move freely, by hand and return by itself when released. (Some drives have a timer to determine when the transfer from high to low rewind motor speed. clean with isopropyl alcohol the R/W head and the cleaner blade to the left of the head, with lint free cloth, if available, if not paper towel. Make sure that the alcohol does not contact the tape. Then, with power on, tapes loaded and ready, run from TAU GO-FWD/BKW all drives and make sure that the tape is kept between the portholes in the columns, and not bottoming down or pulling out of the columns. Test each individual drive for error free write and read, from TAU, or with a card program from the 1401. Drives need to be in optimal condition to do this. Iggy

From Stan Paddock, Wednesday Maint Report - Sat Nov 5, 19:20 PM

Frank King 6.0 Stan Paddock 6.0 Tom Szolyga 6.0 Robert Garner 4.0 Brenda Make 6.0 Ignacio Menendez 6.0 Dale Jelsema 6.0 Stan suggested that the result rated a gold star The punch has been sick from before covid - Tom Szolyga project on the German 1401 System I assembled the biscuit connector into the Serial I/O connector housing. It plugged into the 1401 without error. Next I connected the wire for “1401 running” signal output coming from the connector to the wire for “I/O EXT” signal input going into the connector. If the connector and pins worked properly, pressing the 1401 RUN and STOP buttons on the console should turn the I/O EXT light on and off. IT DID! It works. Next I wired up the 1401 line receiver to TTL signal circuit. I placed a LED on the TTL output. When connected to the “1401 running” signal, the LED should behave exactly like the light on the console. IT DID! It works. Receiving 1401 output signals into the Arduino is now possible. Frank King, Brenda and Dale Jelsema The IBM 083 sorter is down with a power supply problem and is not plugged in. Brenda took pics of the caps in the 083 power supply that was in the museum. This should help fix the problem with the IBM 083 sorter in the Demo room. Other items here, here

There were 26 people in the main demo, plus 8 who wandered in later. International visitors from Germany, The Netherlands, Turkey, and UK.

• The 083 Sorter is completely dead. Won't even power on. Jack, however, made a fine show of doing a pretend sort. The audience appreciated the effort.

• The CT 1402 gave a few random read failures, but we were able to recover, and then they sort of went away.

• CT 729 Tape Drives 1-3 work. Tape #4 seems to work with the TAU, but fails with the Tape Exerciser program.

• DE 729 has only one working 729 Tape Drive

• The DE 1402 Punch appears to be fixed.

There was a previous report that one of the three bottles of magnetic cores was missing. It looks like the two remaining bottles mated and thus created a third bottle. There are now three bottles in the cart.

Demo mic battery charger: If the lights do not come one when used batteries are put into the charger, unplug the charger from the extension cord and then plug it back in. The lights will come on.

from Ken Shirriff - DE 1402 punch - dated Oct 28, 11:58 AM
Stan suggested that the result rated a gold star The punch has been sick from before covid -

Brenda, Frank, and I worked on the DE punch and got it to operate successfully. We took out the punch brush card lever microswitch, cleaned the contacts, put the switch back, adjusted the switch so it closed solidly, and we were able to duplicate the powers-of-two deck and the bigprint deck. Details: The symptom was that the punch would stop with a punch stop error. We determined that the problem was due to the punch brush card lever. I put an oscilloscope across the microswitch and it's clear that the contacts were bouncing wildly. The yellow line is the -20V signal from a cam during one card cycle. The blue line is the other side of the switch. Since the switch is closed, both lines should match. (I verified that this is the case on the CT punch.) Note that the blue line jumps around, indicating that the switch is rapidly opening and closing. We took the microswitch apart and Brenda burnished the contacts. The secret to opening the switches is the pin in the middle and the matching pin on the other side. If you push the two pins in, the switch case separates. Inside the switch is a buckling spring mechanism, not what we expected. We put the switch back in but still had problems until Brenda adjusted the switch to close more tightly. After that, the punch worked reliably and we could duplicate multiple card decks. The new decks successfully loaded and ran. We still saw a few punch stops, but they seemed to be genuine problems due to feeding cards. These problems went away, but there could be lurking problems with another switch. We also got a few punch check errors due to non-blank cards in with the blanks. But overall the punch seems to be working successfully. Stan has ordered a replacement microswitch from Greece in case this one fails again. Ken

from Ignacio Menendez - Status of CHM TAPES

Connecticut system: Tape 1 was missing taper pin on right hand reel hub, causing hub latch to allow tape spinning on hub, and tape dumping. tape pulling out of left column during forward motion: found sparking on left forward clutch, commutator to carbon contacts; re-aligned brush block closer to clutch rings, by about .020” All 4 tapes working OK for demo, mechanically only. Did not have enough time to do data W/R tests. German system: Tape 1: Has power problems A/C comes up, but DC +12 v missing and tape does not complete power up. Attempted to locate +12 v wiring from SMS logic down to power supply cage below. I could not find wiring diagrams on this ALD book, that has this tape s/n Will take a bit of time to trouble shoot. CPs set and reset Ok, none was tripped. Tapes 2 and 3 going forward stop at the same exact time with ‘tape indicate’ always at same time and place going forward; there is no end of tape sticker on either one. Looking at tape 2, noticed right prolay’s idler shaft has moved 1/2 way out, missing retaining clip, and screw is laying there by prolay and head cover. Will replace or make a clip. Only tape 3, is OK mechanically; tape 2 will be. As soon as the idler shaft retaining clip is replaced. It nice seeing you all, enjoyed working there again at CHM. Iggy

from Stan Paddock, People Present, DE Power, 083 - dated October 28 8:50 PM

People who attended the CHM were: Frank King 6.0 Stan Paddock 6.0 Tom Szolyga 6.0 Ken Shirriff 6.0 Marc Verdiell 6.0 Robert Garner 4.0 Brenda Make 6.0 Ignacio Menendez 6.0 German Power Supply: Frank, Robert and Stan took further measurements on the three phase power lines between the Power panel and Pacific power system. The labels on the Pacific will be updated when the data is provided. Robert, Iggy and a third person replaced the main cover over the power panel. IBM 083 Card sorter: While not helping visitors using the IBM 001, Frank is trying to fix the IBM 083 card sorter. It appears that the ferroresonant part of the high voltage power supply is not resonating. Some time in the past, a part of this supply was re-wired and now it does not work. We have access to another IBM 083 to inspect as how the power supply is supposed to be wired. Stan

from Ken Shirriff - DE 1402 punch - received Oct 19, 4:05 PM

Frank, Brenda, and I worked on the DE 1402 punch today; Brenda is a new member of the 1401 team. Summary: the "punch brush card lever" microswitch seems flaky and probably needs to be cleaned or replaced. Background: The 1402 punch has multiple card levers that detect a card's path through the punch. If a switch isn't activated at the right time, the punch assumes there is a jam and triggers a punch stop. We are encountering problems with the punch brush card lever that causes Punch Stop errors when punching. Brenda adjusted the microswitch's position so it would open and close properly, but that didn't help. We looked at the signal across the switch with an oscilloscope: This shows the input to the switch (yellow) and the output from the switch (blue) for part of one card cycle. The yellow line shows the -20V signal when the cam closes. The switch should be closed at this point, so the blue line should track the yellow line. However, the blue line drops down to the yellow line repeatedly, along with 100 V spikes, presumably inductive kickback from the relay coil that the switch drives. The switch should be solidly closed at this point, but it looks like it's continuously bouncing, probably from vibration. My guess is that the contact is corroded/pitted/bad so vibrations are causing the contact to bounce open and closed. Next week we plan to look at the same switch on the CT machine, to verify if the DE switch is bad, or if this is the typical behavior. Maybe the contacts can be burnished on this microswitch. Looking at the photo right now, I'm not sure if the wire on the left is screwed down all the way; that's another thing to check. Ken

from Marc Verdiell - received Oct 19, 5:07 PM - IBM 029 keypunch

Brenda, It was great to meet you! Welcome to the fun! And my update on the 029 punch. It had a bit of a regression after I got it working last time, with the I key failing again but in a different way. It’s been corrected, and now things seem to be holding up. I punched many “all characters” cards and they were all perfect. The 029 is all buttoned up, but Stan suggested we re-test it again next week before we move it to the Babbage room or wherever we want it, to make sure things are stable. Seems like a good idea to me. Marc

After discussions with Marc and others we decided to run on DE because the CT 1402 was having trouble reading cards.

While readying the DE tape drives we heard a loud metal snap from drive #3. A lever near the rightmost vacuum column had dislodged. We were able to point this out to Frank.

The 083 was not putting any cards in one column (still). This week it was the ones column. This isn't a big deal for our quick sorter demo. I think Dale is still working on the 083.

Other than these minor issues, the demo ran smoothly.

We inadvertently left CT tape #3 loaded when powering off. We had prepped the CT tapes before the demo when we thought we were going to run on CT.

Unfortunately we lost one of the vials of cores and the USB cable. We had passed two core vials but only one came back. This day, as always, I mentioned that we are only passing the objects and that they are not souvenirs.

Pat

The problem was identified to Luis Valencia, CHM facility contact.

Luis contacted an electrician to replace the suspected breaker.

After the replacement, the Pacific Systems power converter started acting up.

Luis contacted the electrician to investigate the problem.

The electrician determined that the socket where the new breaker was inserted was faulty.

The electrician was called back for the third and moved the circuit breaker and wires to an vacant socket in the power panel.

After the transplant of the circuit breaker, everything was powered up including the German IBM 1401 system.

All problems identified were corrected.

Thanks to everyone involved in solving these problems.

Stan Paddock

Ken Shirriff and Stan continued work on the German 1402 card punch.
Ken found documentation on the card sense levers. There are FIVE of these little buggers and any one or more of these can cause a PUNCH STOP .
We have checked card levels 1-3 and decided to check number 5.
It was stuck open!!!
We removed the stick and cleaned the contacts.
While Ken and I were in the 1401 room, the power to the German machine was disconnected due a circuit breaker problem so we could not check the problem.

------------------------------------------------------------------

Marc got the keyboard for the public keypunch reassembled.

After fixing a couple keyboard problems, Marc punched all valid punch values,

At the end of the day, inspection of the card, what should be a Z printed as a M.

On the good side, this is not a keyboard problem but a printer problem.

-------------------------------------------------------------------

Tom is now working on a cable from the IBM 1401 serial port and the BLUE BOX II.
This is a part of the IBM PC to 1401 data link like the same functionally that exist on the Connecticut system.

-------------------------------------------------------------------

Tom Szolyga is learning about how an IBM 083 works.
When you run the sorter, while it looks good, it puts cards in the wrong pockets.

-------------------------------------------------------------------

Thursday, October 6 Repair of the circuit bracer for the German system.
After testing various parts of the power links of the power going to the German system, it was identified the circuit socket in the Power Panel was defected.

Luis Valencia called in the electrician to move the circuit breaker to a vacant location in the power Panel.
Power was applied to the German system and the system worked as before.

Ken, Marc and I were hoping that the punch would come back to life, ( sigh )

A review of the problem was a lack of documentation for the German three phase power.
I made two labels that identifies the input and output for the Power Converter and attached them on the back of the Power Converter.
 
(Click to enlarge.)

Stan

Pat and I gave the demo to about 20 people. Most of the quests were local with a few from Germany. DE was still circuit breaker limbo thus we depended upon CE to do the job.

There have been reports of CT not loading Bit Print during the demo. I decided to play it safe. Big Print was loaded before the demo. We periodically ran Big Prints before the demo to exercise the card reader. We did not reload Big Print during the demo but demonstrated it as already loaded.

There were three(?) candidates for 1401 Demo Operators to whom Pat talked while I set up the demo. My wife, Kathleen, another 1401 Demo Operator candidate was also present. She stepped in to help with the guest key punching for Big Prints after the demo.

Problems:

CT: No problems with CT but we did not challenge it to load programs during the demo.

Mic #1: Its headset failed shortly before the start of the demo. I managed to tear open the spare headset and get it installed just before the demo started. I have ordered a new spare headset.

Demo Battery Charger:I noticed that one of the mics had one non rechargeable batteries installed. I assumed that there was a problem with the charger. There was. The charger was plugged into the wrong socket.

When you put used batteries into the charger, the lights should come on (see picture). If they don’t, ensure that the charger (White cable) is plugged into the right socket (see picture). The left socket does not, for some reason, supply power. The charger plug sometimes mysteriously gets moved from the right socket to the left one.

Paul

Reviewing the circuit breaker situation with Dale and Stan today, it’s clear that we do not need to replace the breaker panel, nor increase the breaker capacity from 90 to 100 A, nor change the breaker type, nor increase the wire gauge to the Pacific Power unit.

The intermittent DE 1401/Pacific Power breaker connection was due to a loose bolt that (is meant to securely) attach the breaker’s metal tab to the buss-bar, photos below. Jogging the whole breaker set is what caused the sparking last week at that bolt (photo below). Perhaps 17 years of on-off cycling caused the bolt to loosen (the Pacific Power unit was procured in 2005). The bolt socket/hole seems to be permanently damaged (we don’t know why/how).

Our proposed straightforward solution (for the electrician) is to just move the current (recently installed) set of three DE breakers upward three positions in order to bypass the damaged bolt hole (while also moving upward the CT breaker set). It looks like there may be sufficient spare wire length, so this could be a painless alteration. The damaged and (otherwise remaining) unused breaker positions can be covered by filler tabs.

The rationale:

1. Per Ron Crane’s 2016 measurements, the DE 1401 Pacific Power’s input currents are 24A for phase-1, 25 A for phase22, and 26 A for phase-3 (total of 75A). This current load is well below the 90A-per-phase breaker ratings (total of 270A). We have no plans to ever increase the loading.
2. Ron Crane also measured a Pacific Power current spike of 600 A. According to its spec (below), our breaker — Siemens Type BL, HACR — can properly handle current spikes under 700A.*
3. The electrician apparently deduced that the Pacific Power current draw was 100A (per phase) from the (exceptionally faded penciled) sticker on the back of the unit/rack:
   

Our (fixed) input supply to the Pacific Power is about half that, 15.6 kVA (= 208V * 75A).
(The power load to the DE 1401 system is likely about 10 kVA, or about 15A per phase (= 10,000 kVA / 220V.)

The Pacific Power 390-G unit was previously used at the IBM Cottle road site in their EMC testing lab, along with a second unit, so perhaps it may have been maximally loaded there. We should consider altering the sticker to our current usage, say a conservative 30A per phase (not 100!).

Stan is talking with Jennifer to communicate our information and proposed plan to the electrician.

— Robert

p.s. Photo of the breaker panel. The 3-phase DE breakers are lower left and 3-phase CT ones above them. Note the many empty positions, particularly above the DE & CT breakers. Also the wire gauge to the main breaker is only slightly bigger than those to the DE Pacific Power unit:

Pointing at the loose buss-bar bolt of the middle phase of the 3-phase Pacific Power breaker :

* Looking up the trip curve for our Siemens Type BL, HACR Type, beakers…
https://assets.new.siemens.com/siemens/assets/api/uuid:d6e2e881-6e9c-4488-af64-f5a76394f644/sie-tc-qp-bq-bl-45-125a-2-3p.pdf … our measured peak inrush current of 600A is just below the breaker's trip point of 700 - 1000A:

Also, the ratio of our peak 600A spike to the breaker’s rated value of 90A is 6.6x. From the breaker’s trip curve chart, that 6.6x multiple is within the breaker's “no trip” zone on the left side of its chart:
(Note that this 6.6x value should be used on the x-axis of the trip curves, not the 24x value I referred to in my email).

Detailed notes:
A punch stop indicator happens if there is something wrong with the card motion, detected by the various card lever microswitches. This is different from a punch check, which happens if the data read from the card doesn't match the punched data. Punch stop is computed using relay logic in the 1402. (Unlike punch check, which is generated by the 1401.)

The following diagram from the 1402 CE service index shows the card path through the punch, and the various card levers. A punch stop is triggered if a card gets stuck somewhere, doesn't end up where it should be, and fails to trigger a card lever. Note the stacker card lever, after the second punch brush and before the stacker.

The following are the specific checks that can trigger a punch stop:

• There are two checks if the punch clutch is impulsed at the wrong time, causing a punch stop.
• If the hopper card lever is triggered and the throat card lever is not, then it's a punch stop. I.e. the card didn't feed from the hopper correctly.
• If the punch brush card lever is triggered but not the die card lever (or vice versa), then it's a punch stop. I.e a jam in the punch mechanism.
• If the throat card lever is triggered but not the die card lever, then punch stop. I.e. a jam before the punch mechanism.
• Finally, if the punch brush card lever is triggered but not the stacker card lever (unless the stacker was inhibited), it's a punch stop. ** Remember this case.

This logic diagram from the 1402 CE Service Index represents the cases above. Note that the gates don't match modern symbols; triangles are AND gates and semicircles are OR gates.

This logic is implemented with relays. The card levers trigger various relays, and the relays are connected in series and parallel to implement the AND/OR logic. The relays are on page 11 of the schematics, shown below. For instance, the DIE CL DELAY relay and PCH BR CL relay are in series, implementing the fourth AND gate above. (PUNCH CYCLE PL-7) is the cam at the left below, in series with the relays.)

We looked at the card path in the punch and Stan found a switch that wasn't closing. The photo below shows the offending switch, the stacker card lever (STK CL). The switch's left contact was bent out about 30 degrees and caught on the metal frame, so the switch couldn't close. I touched it and it popped back into position. Stan burnished the contacts and checked the resistance. The failure of this switch explains the behavior that Stan saw: the card would get punched and then the punch check would occur. This switch ensures that the card enters the stacker after getting punched, so if it is stuck open, the punch doesn't see the card reach the stack and thinks there was probably a jam.

Ken

From Robert Garner, responding to Luis Valencia

Luis, > I am waiting on proposal to replace the breaker and wiring with 100AMP. Thanks for the update on the DE 1401 breaker status! > according to any Electrician, machine pulls nearly 100amps + when it first turns on Thanks for sharing the electrician's concerned about inrush current (in our case generated when the Pacific Power converter unit turns on). In our 2016 posting and scope photo (below), Ron Crane measured a peak inrush current of 600 A for what looks like less than a millisecond, with the overall impulse lasting about 8 milliseconds (i.e., half of 60-Hz cycle). That 600A peak value is 24x the steady-state measured value of 25A (per phase). I’m not sure how upgrading from 90A to 100A addresses the inrush problem. We may need another type of breaker (designed for power supplies like our Pacific Power unit, see footnote below). Could you let us know when the electrician will be back in? So that one of us could meet with him, possibly turn on the Pacific Power unit, etc. Thanks, — Robert p.s. The manual for our Pacific Power 390-G unit is here: http://ibm-1401.info/pictures/PacificPower-390-G-Operation-Manual_PN_114250-F.pdf However, it doesn’t say anything about its inrush current (only talks about its ability to handle 10x inrush motor loads). I’ll contact Pacific Power to ask about inrush current and any circuit breaker recommendations based on our configuration. This circuit breaker suppliers' web site… https://www.wolfautomation.com/blog/a-quick-guide-to-circuit-breakers/ … suggests that our system could use a “D-type” breaker. This "trip curve” chart shows that a D-type breaker doesn't trip as long as the inrush spike (of 24A in our case) is under about 3 milliseconds (which is likely the case based on Ron’s scope trace below): click to enlarge

Info from Ed Thelen

I fully concur with Dale Jelsema and Robert Garner (above) About the inrush current - this diagram is a part of page 60 of the Pacific Power 390-G unit (mentioned above).      Note the multiple large capacitors ( C1, C2, ... ) at the outputs of the input rectifiers (multiple 543004s and 543005s ). These cause the very large but brief inrush current when the unit is first turned ON.      The resistors (R1, R2, ...) are called bleeder resistors to slowly drain the charge from the capacitors when the unit is OFF - to prevent shocks to unwary finger pokers. click to enlarge I think that it absolutely vital for the specifying electrician understand that this is the cause of the very brief, very high current at unit turn on. This very brief current will not appreciably heat the currently installed #4 wiring. A licensed electrician should understand this, IF the information is correctly presented!!      Most, if not all of the restorers, (if present when the electrician is present) can provide this information correctly.

Lately I have had several visitors ask about the "pilot" lights on top of the 1401's and the 083. I explained that their purpose is to show our dedicated restoration team which boxes have live power.

Before the demo Robert Garner was escorting a group of visitors who had hardware backgrounds. They punched name cards but declined getting them printed on the 1403.

Before the demo CHM facilities staff and electricians were present working on the DE power circuit breaker panel. We were running on CT. I asked them if that was a problem given that the CT power circuit breakers are adjacent to the DE breakers. They said no. At five minutes before demo start time they wanted to involve me in their discussion. I declined due to the time and expertise needed. Luckily restoration tam member Dale Jelesma was present and was able to help them. See his report for details.

As always, we ran BigPrint before the demo started to verify satisfactory operation. It ran fine. However, during the demo the CT 1402 would not load the BigPrint deck. Bill and tried these actions:

1. Checked for obvious card problems (e.g. damaged cards, etc.).
2. The deck had a "trojan" card (No Op) before the actual first card. Removing it had no effect.
3. Ran about 30 seconds of NPRO several times.

I then asked Bill to attempt to power up the DE machine so that we could move the group there. While he did that I carried on with the components part of the demo (SMS cards, core memory, big cable). Bill then reported that the DE was unusable. The electricians had left tape across the circuit breakers to indicate that it should not be powered up.

Some time had passed since the last card read attempt, so I decided to try to read another deck (Powers of 2). Fortunately it loaded fine. After explaining the 1403 operation we loaded the same BigPrint deck that failed previously, and it ran fine. Hallelujah! The tapes and the rest of the demo went without a hitch.

I know the restoration team is aware of this issue, and that intermittent problems like this are very difficult to diagnose. This problem as been happening for a long time. Here is my best description of the way it has been failing recently. Note that it doesn't fail every time.

1. Turn on 1401. Run 30 seconds of NPRO on the 1402 reader. Within 5 minutes run a program, usually BigPrint. It runs fine. Run Powers of 2, which also runs fine.
2. Machine sits idle for 30 - 60+ minutes until demo starts.
3. Attempt to load a program. The motor starts but no card is read. At this point, NPRO doesn't help.

As always, kudos to the restoration team. Without them there would be no live demos.

FYI this issue will have to be taken care on one day Museum is close so we can actually disconnect power to the panel completely, Electrician will be here to take care of the panel issue.

Electrician mentioned that if we resolve the panel problem, there is actually another issue with the existing wiring and breaker connected from the panel to the machine, Machine pulls 100AMPs, Breaker is rated for 90AMPs and wiring is size 4AWG which is not rated for 100amps, that being said if we do not replace the breaker and wiring with the right size/power rating , the existing breaker will keep on tripping.

Exiting breaker needs to be replace with a 100amps and 2AWG wiring.

I will ask Electrician to give me a proposal to replace wiring, breaker and panel repair.

Let me know if there are any questions .

Luis Valencia
Facilities Manager

I was onsite at CHM today (Wed, Sept 28) working on the 083 sorter. The German 1401 was powered down. About 3 pm CHM Facilities had an electrician re-look at the new DE main panel circuit breakers (3 breakers ganged together) that was installed a few weeks ago..

The new German 1401 circuit breaker is bolted to the 3 main 100 amp buss bars within the main wall panel. When the breaker was turned on, all seemed okay, until one of the 3 output lines was pushed toward the new breaker (which caused the whole breaker block to move a little). Then there were sparks and arcing where the center breaker input lug is bolted to the buss bar. Ends up, that bolt looked like it was cross threaded when installed, as the bolt was almost burnt thru. ( Frank King was also connected by speaker phone during this time -- Thank You Frank for talking to the electrician).

Discussion with the electrician and CHM staff that maybe parts of, or the complete inside of the wall mounted panel would need to be replaced. (which would most likely cost $$$). Instead, I suggested that maybe the circuit breaker be removed, power to the whole panel be shutdown, and the damaged breaker mounting hole be retapped to the next size bolt thread.

Tomorrow, the electrician and CHM facilities will power down the main wall panel, remove the DE breaker, and determine what arc cleaning (or damage repair) is needed to the panel busbar.

- - - Bottom Line - - -

Early on, I did power up the Pacific Power 390-G converter twice, to confirm that voltage was getting to the converter, but it was off during the time when the main panel DE breaker threw sparks and arcing,

The DE 1401 system was never powered up. My feeling is the current main panel DE 1401 breaker itself is okay, It is just the one mounting lug that ties the center (?) breaker itself to one of the 3 main panel busbars.

If anyone has additional questions, contact me. I will be onsite CHM next week Wed.

Sincerely,
     Dale Jelsema
         Gilroy, Calif

CT performed admirably. Big thanks to the restoration team.

Bill

Background from recent status reports.

1. Problem switching the circuit breakers for the German system.
2. CHM called in an electrical contractor to replace the three wire circuit breaker.
3. The following is a report from Frank King on the next work day.;

   "Hi, Stan,
   
   The German 1401 power converter acted up for the first time I have ever seen.
   When I tried to power on the German 1401, the power converter went down immediately; it has an internal circuit breaker that will reset on its own.
   After opening the 1402, looking at the 30 amp circuit breakers, I tried it again (It had reset by this time).
   Then, Mason and I took the tape circuits off line; that didn’t help.
   Mason then suggested we trip the 1402 circuit breakers one at a time.
   When we tripped the inner most 30 amp breaker the converter didn’t go down when powering up the German 1401.
   
   We then reset the breaker and tried it one more time.
   It stayed up.
   So we restored tape power and tried it again.
   It stayed UP.
   
   Frank King"

4. The next work day, everything seemed to be OK.
5. Bill Newman and Stan Paddock decided to come in on a Friday work day.
   All of the problems shown in number 3 above showed up again.
   Bill brought out a electrical meter and checked the power line from the circuit breakers on the power panel and the power convert.
   When the system was acting up, there was a missing leg from the circuit breakers.
6. The problem was traced down to the three wire circuit breakers installed in number 2 above.
7. We would request the CHM to have the electric contractor come back and fix the problem.

At 3:00pm Tim Robinson, Bill Worthington, and I gave the demo to 42 visitors. We ran on CT. It and the rest of the equipment that we used performed well.

SPECIAL DEMO

In the evening we did a special demo for a group of 50 Arizona State University Electrical Engineering alumni. ASU is Robert Garner's alma mater (go Sun Devils). Last week Jack Ghiselli used his revised and improved banner program to print two welcome banners for the group.

We ran on CT, which performed perfectly. Robert was in the machine area to help. I gave a slightly shorter than usual demo (about 25 minutes) due to the late hour. It was well received.

As usual, thanks to the restoration team for providing working CompuSaurs.

Frank King, Mason King Dale Jelsema and Mason King continued work on the German 1402 card punch. Several circuits were checked and unfortunately the circuits checked worked as designed.

Frank and Dale

Mason King learning how the 1402 punch works.

Dag Spicer, the Museum’s senior curator paid us a visit. A large number of visitors wandered into the 1401 room. Dag played docent and to the random visitors told them about the IBM 1401 and answered questions about the CHM Museum..

Marc got the keyboard for the public keyboard reassembled. Unfortunately the keypunch rejected the implant of the keyboard. We are looking for success next week.

Stan

We ran on CT, which performed well. We got a few read check errors on the CT 1402 Reader immediately after power-up, but these disappeared after some minutes of warm-up. Tape Drive #1 is still marked Out of Service, so we used Tape Drives #2, #3, and #4. We didn't see any problems with #3 as Pat had seen last Wednesday.

All three 026 Keypunches worked OK. The Amazing Restoration Team apparently fixed the poor printing on Keypunch #3 (closest to the door) and the failure to feed on Keypunch #2. Having all three Keypunches made the BigPrint punching go quite quickly.

Apparently, when I did the demo last Thursday, I somehow knocked the A/V battery charger cord from the wall, so the rechargeable batteries didn't get charged. We loaded disposable alkaline batteries into the radio microphones for the demo. Paul found that one of the power outlets in the A/V closet didn't power the charger, so he switched to the other. The charger should show red lights when it is charging. Rechargeable batteries should be ready for the next demo.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

We used CT which generally ran well.

026 Keypunch #2 is still INOP (doesn't feed). #3 (nearest the door) was printing too light to read. We tried reversing its ribbon and that seemed to help a little, but it probably needs a new ribbon. So only 026 Keypunch #1 (farthest from the door) was usable for the demo. #1 generally worked well, but it still has the problem where cards sometimes jam up when transferring from the Read station to the output stacker. Usually we can pull them out by hand, though.

The 083 Sorter worked OK for the demo. It still seems to handle input cards roughly, crumples some, and sometimes the last few cards of an input deck don't feed. It's also making some unusual mechanical noises.

The 001 Manual Keypunch, which was INOP a few days ago due to card fragments jammed into it. Somebody apparently found a card saw and cleared out the fragments. The card saw is on the CT 1402. We saw some clues that it might have been Stan Paddock. Whoever it was, thank you.

We found CT 729 Tape Drive #3 loaded with a bunch of loose tape dumped in the vacuum columns. So, for the demo we used only Drives #2 and #4, which ran fine. After the demo, we manually rewound the loose tape back on the the reels of #3, and were able to get it to rewind/unload. Not sure if it has problems or not. Drive #1 is still marked OUT OF OPERATION, so we didn't try to use it.

After the demos, we punched some object decks on the CT 1402 Punch, which worked beautifully. Thank you, Restoration Team.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

I ran on CT, which worked well. I did not prep DE because Frank & Mason were still working on the 1402 punch. It was not needed.

The only CT problem was that drive #3 (2nd from right) dumped tape into the right column when doing a rewind. Drives #2 & #4 worked fine.

026 keypunches #1 and #3 ran fine, as did the 001. I didn't try 026 #2, which looked like it was being worked on. With the small group two keypunches were sufficient.

Aug. 24, 2022

Sept. 7, 2022

Robert Garner took before and after pictures of the DE system main breakers. "… it appears that they replaced all 3 with identical units. (It’s hard to discern the subtle differences.)"

We used CT which generally worked well. We did have a problem with what seems to be a bad spot on the CT 1403 printer ribbon. We had tested BigPrint and Powers of Two before the demo and printing looked good. However during the actual demo, our first BigPrint printed so light it was mostly unreadable (see photo below). We re-ran it three times and no improvement. Kind of embarrassing, but we skipped that and continued with the demo. To recover, we left the CT1403 print chain engaged, so that the ribbon would keep moving while we talked about other things. Eventually, I guess the ribbon got to a good spot, and we were able to print successfully later. Or perhaps we don't have Paul Laughton's clever touch at slamming the carriage closed firmly, and it's not really a ribbon problem. Unsure. Suggest following demo'ers check for this.

The 001 Manual Keypunch is INOP. It has a fragment of a card jammed into the mechanism and we were unable to clear it. Sorry for my ignorance, but does the 001 need tools to clear a jam? We left a sign on it and hopefully visitors won't damage it further.

For the microphones, we used Paul Laughton's rechargeable batteries. When we put the old batteries into the wall charger, we don't see any blinking lights. Is the charger still working? Next demo please check whether we got the batteries re-charged correctly.

Some continuing minor problems continue, none of which affect the demo:

• Keypunch #2 is INOP. Doesn't feed or register cards. We left a sign on it. Important only if we have a very large group.

• CT Tape Drive #1 is marked INOP so we didn't use it.

• The 083 Sorter moves cards sufficiently to demo. However, it doesn't REALLY sort correctly, so you cannot put a deck in sequence. As a result the sample Ken-Ross-style sort data decks I produced last Wednesday have lost my carefully marked First and Last cards and top markings (artist's "sigh" here). Unfortunately, the only card stock I'd found last Wednesday was completely unprinted, so it's difficult to find the correct orientation for 12-Edge, 9-Edge, and Front/back. Again, this is NOT a big problem for the demo.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

I was in for 2 hours.

Frank and Mason worked on the DE 1402 punch.
(Mason told me that the Pacific Power breaker tripped when he first turned on the DE 1401.
Tried it again w/breakers in 1402 off, then back on, then DE powered up the 2nd time.)

Yes, Dale Jelsema was in today! < dale . jelsema @ gmail . com >
Photo here: http://ibm-1401.info/TeamBios.html#JelsemaDale (I’ll ask him for his bio.)
He asked if he could borrow some of the 1401 manuals to get up to speed. (like the 1401 CE manual). I replied no problem.

I didn’t see Marc. Tom [Szolyga] was in.

Cheers,

— Robert

• Created a real schematic for the Blue Box line driver and line terminator circuits.
  
• Ran a simulation of these two circuits connected to each other.
  
• Collected the parts for the next version of the German Project breadboard and assembled them. (See attached) I has the ATmega 2560 on the bottom, the board with terminal strip screws for each signal is in the middle and the diagnostic display is on top. There is a plug board for test circuits too. Everything is mounted on a plastic plate so the breadboard circuit will not fall apart.

The DE circuit breaker refused to be "unbroken" as previously reported. Emails from Robert Garner and others indicate that the problem is being investigated.
(See report below this report)

The CT 1403 printer was left in an inoperable state. The Ink ribbon was stuck at the end of the reel. The paper was jamming as it moved. Robert Garner, Frank King and Bill teamed up and got it fixed before the demo.

We had about 50 guests with visitors from the UK, Germany, Columbia, Egypt, Georgia (the nation) as well as from the USA.

Just before the demo started, I noted that the Mic #2 battery was at 2/3rds. I replaced the batteries.

The 1/2 hour demo went well with virtually all guests remaining in the room through to the end of the demo. We spent about 15 minutes doing Big Prints after the demo.

A big thanks to Bill, Kathleen, Robert and Frank for their able assistance.

Paul

The (90-Amp) circuit breakers for the DE (German) 1401 adamantly (after >10 attempts) do not engage/remain on, per the following video:
Editor's Note: I included this frame copy from the movie, instead of a link to the 20 MByte movie. The movie shows the (90 amp 1401 German) circuit breaker being changed from OFF position to ON position and immediately going to the TRIPPED position as shown.

It appears that we’re now unable to turn on the DE 1401.

Hoping an electrician can replace ‘em.
(I wonder if there's a circuit breaker model spec’d for more frequent cycling, say several 100 on-offs per year?)

Thanks(!),

- Robert

PS. The Pacific Power unit was turned off during the attempts to engage the circuit breakers.

---

Jennifer Alexander e-mailed "Facilities Manager Luis will follow up on this."

from Stan Paddock

People who attended the CHM were:

Frank	King	6.0
Stan	Paddock	6.0
Tom	Szolyga	6.0
Marc	Verdiell	6.0
Robert	Garner	2.0
Mason	King	6.0

Frank and Mason continued there work on the German 1402 card punch.
They traced the problem to permissive relay 26.
Frank and Mason pulled all of the permissive relays related to the punch and brought them to the workshop.

We have a permissive relay tester that we have not used for years.
When we tried to use it, we found that the power supply for the HP laptop was defunct.

I contacted Dennis Cassar of the CHM IT department to see if he could supply a replacement power supply.
In less than 10 minutes, he brought a replacement power supply to our workshop.
Thanks Dennis.
I showed Mason how to run the permissive relay tester.
Mason took off running the tester as if he had been using it forever.
Relay 26 was totally bonkers and was replaced.
Another relay was also totally bonkers and was replaced.
All relays were replaced into the German IBM 1402 and tested again.
Damn thing punched card!
Now if did the punch without a PUNCH CHECK and a PUNCH STOP error, we would done.
Way to go Frank and Mason.

Stan

It appears that at least one of ganged circuit breakers 35-37-39 (labelled "1401 GERMAN") is faulty. Recommend replacing them all. Until this is fixed, it is impossible to power-up the DE 1401.

On Saturday, 8/20/2022, Steve Madsen and I gave the 1401 Demo to 48 visitors, and then a mini-demo for 2 visitors afterwards. We had visitors from all over the USA, and foreign visitors from the Czech Republic (near Brno), France (Toulouse), Japan (near Tokyo), and the UK (north of London). This particular group had lots of technical questions after the demo was over, so we spent quite a bit of time simultaneously answering and running BigPrints. We demonstrated the 083 Sorter, and ran the demo on CT, using 729 Tape Drives 2-4, since #1 had been switched NOT OPERATIONAL. During pre-demo setup, we worked around several hardware problems (described below), and the demo itself went well.

First, DE Power:
Pat Buder's report from Wed 8/17 suggested that the CT 1402 was refusing to read cards, and recommended using DE for the demo. When we powered on the breakers for "1401 GERMAN", they appeared to turn fully on, but we were unable to power-on the Pacific Power 60-to-50 Hertz power converter. A few green LEDs came on, but we couldn't turn on the three voltage displays at the top. This is exactly the symptom Paul Laughton reported in our email exchange of 8/13. I continue to believe that the problem is in the wall circuit breakers, not the Pacific Power unit. I turned the "1401 GERMAN" breakers off and then firmly back on. This apparently worked, because we were then able to turn the Pacific Power unit on normally.

Unfortunately, when we tried loading decks on the DE 1402, it refused to read cards. We tried using NON PROCESS RUNOUT to exercise the 1402 mechanism, as suggested by the Restoration Team. But, no luck. So, we decided to try CT, although both Pat Buder (Wed 8/17) and Paul Laughton (Thurs 8/18) had reported that the CT 1402 was refusing to load decks. For us, the CT 1402 worked perfectly. I suspect this is due to the Amazing Steve Madsen, who gave it a "stern talking-to".

The Amazing S. M. also demonstrated his extensive IBM training by clearing the card jam left in the 083 Sorter as an exercise for us. It was an ugly multi-card jam, and you should see the Amazing S. M. go to work with needle-nosed pliers. He got that 083 puppy working perfectly in time for the demo. Yay, Steve!

One minor issue:
After the demo, while we were rewinding CT tapes, 729 Drive #2 dumped tape into the bottom of the input vacuum column. We were able to Unload and manually wind the tape back on the take-up reel, and then it was OK. Possibly an intermittent vacuum-column problem?
Happened only once.

After the demo was over and visitors had left, we decided to try loading decks on DE. Guess what?
The DE 1402 loaded decks just fine.
Perhaps this means DE needs some warm-up time? It had been powered up for 40 minutes while we ran the demo on CT.

More about DE Power:
Now, we powered down the DE1401, the Pacific Power unit, and the "1401 GERMAN" circuit breakers. Just for grins, we decided to try power-on one last time, and I'm glad we did. This time, we found that the ganged 34-37-39 ("1402 GERMAN") circuit breakers would not turn on. When you flip the breakers on, they immediately bounce back about half-way, and give no power to the Pacific Power unit. Just to be clear, now they are WORSE than before. As noted above, I'd recommend that CHM Facilities replace all three breakers. Until then, DE is unusable. It would be nice to fix this before the Restoration Team and Demo Team come in Wednesday 8/24.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

The three ganged circuit breakers that supply the Pacific Power 60-to-50-Hz power converter for the DE 1401 are tripping.
Either the circuit breakers are degraded, or it’s possible that the Pacific power 390-G unit is tripping them.*
While we can perform a few diagnostic test on the Pacific Power unit,** it might also be helpful if we could get an electrician in to swap out the circuit breakers, just to eliminate them as a possible source of the problem.

Thanks(!),

— Robert

* The 390-G comprises three independent power converter units, one for each phase:
http://www.ibm-1401.info/pictures/PacificPower-390-G-Operation-Manual_PN_114250-F.pdf
One of them could be tripping its circuit breaker, but because they’re ganged, all of them go belly up.

** With the DE 1401 turned off (no load), we could disable each of the three converters one-by-one to see if one of them is tripping the breakers. But it may only be happening under full load, which would involve further diagnostic testing: looking at the phase current waveforms as power comes up.

If the power converter is ON when the GERMAN circuits are turned on, frequently the circuit breakers,

If the Power converter is always turned off before turning the GERMAN circuit breakers off, this problem will never happen.

Stan

Stan, et al,

> If the Power converter is always turned off before turning the GERMAN circuit breakers off, this problem will never happen.

Jack’s message implied that the Pacific Power converter was indeed off before he turned on the circuit breakers (i.e., the conventional DE 1401 bring-up order):
“When we powered on the breakers for "1401 GERMAN", they appeared to turn fully on, but we were unable to power-on the Pacific Power 60-to-50 Hertz power converter. A few green LEDs came on, but we couldn't turn on the three voltage displays at the top. This is exactly the symptom Paul Laughton reported in our email exchange of 8/13.”

Re: Frank’s note…
"The circuit breakers for the DE machines converter have tripped when turning them on for a couple of years at least. A push back reset and then on, has always worked for me. I have never had it fail. It generally trips off about 1/2 the time or less.
This is something to consider. The main circuit breaker for the converter is always off when this has happened. i.e. there is no load on the tripping circuit breakers?”
… reaffirms that we’ve had this issue for some time. As Jack noted, it could indeed be an issue with the circuit breakers, since the power converter is typically off before the breakers are turned on.

Or perhaps our Pacific Power unit (or the 3-phase AC wiring) has an AC leak/low-impedance path to ground or between the phases (that’s tripping the breakers as they’re first turned on)? Recall that Ron Crane modified the Pacific Power unit to help reduce the reactive power (added caps I presume). Perhaps that mod is upsetting the breakers? An electrician could help determine the issue.

Cheers,

— Robert

p.s. I may have confused the discussion by postulating a turned-on Pacific Power converter when the circuit breakers are first turned on. Sorry about that… (After all, as Frank noted, why are they be tripping with no load?)

was giving a demo to a private party Thursday around 4:00 PM.
CT would not LOAD any programs. Pressing LOAD caused the CPU CHECK RESET light to turn on without reading any cards.

Paul

I experienced the same as Paul. Was refusing to read any cards. Then after a while it started to work all of a sudden. CT system also, several occasions.
Marc

We ran on CT, which had the problems described below. All tapes and keypunches worked fine.

Sorter problem
Initially all sorted cards dropped into the reject bin. Choosing a second column had the same results. I reached over to verify the settings of the front panel switches, selector knob, and buttons. I was not in front of the machine so I didn't notice that the SORT/TEST switch was not up. It is not uncommon for visitors to reach beyond the rail to play with these switches, which is what had happened here.
During the struggles, I managed to cause a card jam in the sorter - sorry.

CT Problem
The CT 1402 read and ran BigPrint successfully before the demo. During and after the demo, there were several times when the motor would start but no cards would be read. As Jack, Paul, Marc, and I have recently noted this is a chronic intermittent problem.

Recommendations
I would recommend that docents do not allow visitors to press the 1402 LOAD or START buttons during the demo because this presents an example of unacceptable visitor behavior at times when the lab is unstaffed. We should be encouraging never touching anything beyond the fence.

While CT is closer to the keypunches and more convenient for demos, I plan to use DE until the CT 1402 intermittent problem is fixed.

Pat

An idea of the IBM 029 keyboard complexity cam be viewed on Marc's Youtube series -
IBM 029 Keypunch Restoration 6 - Insanely Complicated Keyboard
For more on the IBM 029 keypunch click here.

Material from e-mails is below

Marc (unexpectantly) noticed that several of the “Interlock Disks” were misplaced from their proper locations (they look like small donuts). Camera, microphone and lamp are for creating Marc's wildly popular Youtube series.

I wonder if that could have contributed to the “A” key becoming stuck (i.e., a missing interlock disk)??

(click to enlarge)
from http://bitsavers.org/pdf/ibm/punchedCard/Keypunch/029/225-3357-3_29_FE_Maint_Man_Nov70.pdf
The diagram is on page 4-41 of that document.

The A-key is repaired, but I think I need to revise my story about the interlock disks, I might have caused that. Anyhow, I fixed that mess and did not lose any disk, but in doing so I created another one, now having to reseat all the springs on the code bars, for the next session I guess. I did not lose any spring either. At least not yet :--))
Never a dull moment.

Marc

response by Marc

I'll surmise that it's a very bad idea. It's too complex and precious of a machine for the average visitor to understand, much less to operate safely. The only thing they'll manage to do is to break it.
Marc

I recall the keypunch room from my student days. 30x 026's about 1/4 of which were always inoperative, even though the IBM FE came once a week to fix them and some of us staff students could undo simple problems.

A not broken program drum was usually unobtanium.

Use restricted to Docent demos sounds like a good idea to me.

Regards,
Grant Saviers

Hi,
Paul Laughton and I demonstrated the IBM 1401 to 40 people. We had visitors from Germany, Toronto, Hong Kong, and China. While running Bigprint we had a reader check and an operator error (pressed LOAD instead of START). That deck was marked because it might have some cards out of position.

We did not start the DE machine, because the Power Converter was not working. All other equipment worked fine.

After the demo, a group of 30 students from Japan came in. We let them punch name cards and ran Bigprint for them.

Regards,
Stephen H. Madsen

Hi Steve,
Great demo report! I'm not exactly sure what you meant by "Power Converter was not working". I have noticed that the "1401 GERMAN" circuit breaker set (ganged breakers 35-37-39) are a little flaky. Sometimes when you flip them on, they bounce back a little and DO NOT TURN FULLY ON. In this case, of course, when you try to turn on the DE Power Converter, nothing happens, since it has no input power. My solution has been to turn the "1401 GERMAN" breakers back off, then forcefully turn them on, holding firmly and verifying that they go ALL THE WAY ON. See if that solves the problem.

When I get back in, I'll run VOBJ to analyze the suspect (marked) BIGPRINT deck and fix it if necessary.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

I noticed the problem with the flak DE circuit breaker. The problem that I noticed was not that exactly. The converter was getting some sort of power. The three phase activation section at the top was not responding to the start button press.

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Frank continued his work on the German 1402 card punch, with the help of his grandson Mason, who clearly inherited the debug-anything genes.
While they tested a number of functions of the 1402 punch, all of those functions seems to be operating correctly.
The story of the 1402 punch continues on.

The docents cited an error with keypunch #1 not feeding cards into the stacker correctly.
Frank using his 50 years experience working on IBM keypunches, fixed the problem quickly.
--------------------------------------------------------------------

From Marc:

I repaired the last of the 3 faulty breakers on Tape drive 4 of CT, and also reconnected its broken wire that was starving a bunch of SMS cards from the -48V they deserved. Some more lights reappeared on the back neon debug panel as expected. I'm not sure if it fixed anything else. I tried to repeat the no-unload fault reported by the demo team, but it did unload (and load) normally. I don't know if I repaired it as a consequence of the breaker or if it's another intermittent fault that will soon reappear. I did not have time to look at CT tape #1 with the reported lazy reel, so that one was left to out of service.

We thought it was a good idea to place a keypunch outside of the barrier's in the 1401 room to be used by visitors when needed.

Sometime when the 1401 room was un-attended , the "A" key on that machine was broken.
Marc volunteered to take the keyboard home and see if he is able to fix it.
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We began the demo on CT. The BigPrint for one audience volunteer part worked well. However, we couldn't get Powers of Two to run. We switched to DE, but same problem. At one point, all four of us were pursuing fixes. We finally got it to work. It was a missing last card. We switched back to CT for the tape part of the demo because that was where we had prepped the tapes. We ran on drives #2 & #3. See Jackk's email for a detailed description of the problems on #1 & #4. One or two drives are sufficient for the demo.

The two 026's nearest the door ran fine. The 026 furthest from the door still has the stacker feed problem that we have documented previously. We didn't use the keypunch outside the rail. The sorter worked well.

We had a few reader checks on CT, but all resolved when the card(s) were read again.

At one point the CT 1403 again had the problem where one half of the page printed much more faintly than the other side. Firmly reseating the gate latch seemed to fix it.

During a slack period after the main demo, Jack ran his VOBJ program on several demo decks. It found missing cards, etc. which he fixed.

Unfortunately this was one of the most problematic demos I've seen. Many of the problems were actually operator errors. During the heat of running a demo with the associated time pressure it's easy to lose track of things. I would make these suggestions to help forestall these types of problems.

1. Prepare both machines for potential use. This includes having a card weight, positioning the tapes, etc. After the demo the backup machine can be powered down.

2. Have two verified copies of each demo program (BigPrint and Powers of Two). Create a separate date card for each BigPrint Place one of each program on the backup 1402 in case it is necessary to switch to the alternate machine.. Run all four of these decks before the demo.

3. Remove all copies of the demo programs from the top of each 1402 except for the ones listed above.

4. I asked Jack to begin marking the date each deck was verified on the first card rather than on a slip of paper that can easily become separated from the main deck.

Pat

I volunteered to make this addendum report on the CT tape drives. Given all the hard work the Amazing Restoration Team has been doing on these tape drives, I'm embarrassed to report any problems, but here goes.

On CT 729 Tape Drive #1 (closest to the CPU), the tape media had a 3-inch long crinkly section a few feet following the start-of-tape marker. I cut the damaged length off the tape, and put on a new start-of-tape reflective spot. Problem fixed.

CT 729 Drive #1 also seems to have a problem with the feed reel. We use the TAU to command the tape to run, and it runs OK for a short while. Then, we observe that the feed reel sometimes doesn't keep up. When the free tape in the left-hand (feed side) vacuum column reaches the top vacuum hole, the feed reel is supposed to start moving and feed more loose tape into the vacuum column. However, sometimes we observe that feed reel is slow, so that the input tape goes farther and farther ABOVE the top vacuum hole. Eventually the entire feed loop is gone from the vacuum column, and the drive stops. The right-hand (take-up) side vacuum column is working correctly. We switched this drive to OUT OF SERVICE.

CT 729 Tape Drive #4 (closest to the entry door) refuses to unload. We switched it to OUT OF SERVICE, but after the demo we had to power down the CT 1401 with Tape #4 still loaded.

The demos ran just fine using 729 Tape Drives #2 and #3, so these are not serious problems.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

We started using CT, but there were so many visitors we powered up DE as well. At first we couldn't get any decks to load on the DE 1402. Stan Paddock looked at it, waved his magic wand, and it healed, so we were able to use it. We had so many visitors we really needed all the docents -- they were all busy most of the time -- and both 1401's. We even used the 029 keypunch in the aisle.

The 1403 Printer on CT seemed to run out of ink, so the printeouts faded away. We fooled with it and the problem went away. Paul Laughton thinks the gate was not fully closed, so that the paper was not tight against the ribbon. We'll watch this tomorrow. The CT 1403 ran out of paper so we put in a new box, which turned out to be pure white, without bars; not a problem, just a surprise. 026 Keypunch #1 (farthest from the door) seems to have some problems moving cards to the output stacker -- Sometimes they hang up.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Ed Thelen here -

Jack's report (above) reminds me of stories of the last half of WWII in Europe -
Frequently, when adequate weather, the American Air Force would declare a "Maximum Effort Day".

If a plane could fly,
    It was in the sky,
        Over Germany

Looks like "we" are demoing "our" Vintage IBM 1401s
    "Maximum Effort"
        To the Vintage Computer Faire :--))

From Marc Verdiell

In my experience the CT does this inconsistent card loading consistently. It won’t pick anything, then all of a sudden it starts to pick the cards and it’s all good from there. I don’t think we ever figured out the problem. We should.
Marc

• Figured out how to get ROPE3 to work with the LaserJet printer. Now I have it printing the ROPE listing in plain B/W, making them readable.
• Sorted through the wires we harvested from the IBM cable/bisque connector to use in the harness for the NEW “Blue Box” I am building. My plan is to use twisted pairs for every signal between the 1401 and the Arduino. There will be a DB25 connector for input and another one for output of the Arduino. Each signal will use a pair of pins on the DB25. If the signals use the same bit ordering, it should be easy to find signals on the connectors. The extra grounds should improve reliability.

CT Intermittent print problem:
Once when running BigPrint a person's name with a "D" printed as a "4" (missing zone punch). I checked that the card was punched correctly and it ran fine the second time. The card was punched on an 026, not the 001. I've seen this problem before but not recently. I discussed the problem with Frank King, who was there that day. He opined that it was not likely a printer problem or a reader problem due to the sum of punches error checking. No harm dome, but the guest wanted to keep both the erroneous and valid printouts. Extra special souvenir. I told him that the 1401 was very reliable back in the day and that we have to allow our Compusaurs a little leeway now.

Keypunch problem:
The 026 furthest from the door often only partially lifts the card into the stacker after it leaves the read station. Usually the card stops at an angle. It's easily extracted and handed to the guest. I'd say it happens 60-70% of the time.

On 8/6 before the crush of VCF visitors started I was duplicating "Decode Cards" (card with alphabet, digits, and most printable special characters) and had an opportunity to observe the problem a little more closely. I never use AutoFeed, but I do press REL/REG or REL/FEED rapidly in succession. I tried slowing down these steps, which seemed to help a little but not entirely eliminate the problem. The other two 026's worked fine.

As usual, thanks to Frank and the entire restoration team for keeping everything humming.

Pat

Kate, as you predicted in your email yesterday, your friend and donor Paula Golden apparently didn't show. However, Kate has lots of friends, so last Wednesday, your other friend Yi Ying, the artist from San Francisco did arrive and Pat and I had a pleasant talk with her. Yi taught me an important factoid: Where do Emoji's come from? Well, Yi apparently created artwork for an Emoji showing Boba Tea (if you don't know what this is, you're over 30). She then formally submitted it to the Unicode © Consortium, who accepted and registered it. It should appear on your smart phones soon.

We ran on CT which functioned perfectly, as did the 083 Sorter and all three 026 Keypunches. We didn't see problems with CT Tape #3 as Pat Buder had reported last Wednesday. The Restoration Team rocks!

Paul Laughton came in to take some photos for the upcoming 1401 Demo Docent training materials. We hope to give a new docent training session in the near future, if CHM can find some candidates.

A/V microphone #2 ran out of battery power at the end of the demo. We accidentally reloaded EBL batteries, and the mic went completely dead. We realized our mistake and re-reloaded disposable Energizer batteries and Mic #2 now works fine. All 1401 docents please note: The rechargeable "EBL" batteries do not work, and neither does the recharging unit. We have put two good-sized packages of disposable Energizer AA batteries in the A/V drawer; please use these for the microphones.

We had hoped to shunt 1401 demo visitors over to the PDP-1 SpaceWars competition starting at 12:00. Unfortunately, some hardware problems on the PDP-1 display forced cancellation. Hopefully it'll be rescheduled in the future.

We still need a 1401 Demo Assistant for this coming Wednesday 8/3. Then, Saturday and Sunday 8/6-8/7 we expect lots of visitors to 1401 demos during the Vintage Computer Fair. We could use at least three docents during those days. Poppy said she'd open up extra slots in the signup system.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Frank continued work on the German 1402 card punch. He got the punch unit timed except of the shaft that drives PC CBs. It is close but not all the way.

A large number of visitors wandered into the 1401 room. While Frank is not comfortable talking to strangers, he played docent and told them about the IBM 1401.
[Ed Thelen here - Stan must be "pulling our leg" !! This is not the Frank King I know !! There is no way a person can call Frank "not comfortable talking to strangers".    ;--)) ]
--------------------------------------------------------------------

This Wednesday, Frank mentioned that the breakers can be opened up and repaired, and that they had done so with many of them previously with Joe Preston. So I took one out (that's the hard part, as they have been soldered in), and indeed, you can open them up easily and repair them. I repaired the one that wouldn't trip (just freeing up and lightly oiling a lazy shaft), and put it back just in time for the 3:00 demo. Since I need to take the two other breakers out anyhow before changing them, I'll try to see if I can repair them too. I suspect it will be even easier, as they both trip but something is wrong with the low voltage contacts. Probably just cleaning the contacts will do. I'll let you know how it goes.

Marc

We ran the demo on CT, using four (count, 'em, four) tape drives, thanks to the hard work from the Restoration Team. All CT, keypunch, and sorter hardware functioned perfectly.

Yesterday, I stopped by and repaired and verified three (3) BigPrint demo decks. These are in the Demo Tray, and have been verified 100% identical. Please use these. There are several other BigPrint decks kicking around (NOT in the demo tray) which don't work, and appear to be lacking cards at the end. Please don't use these until they've been repaired. There is one (1) Powers-Of-Two deck in the Demo Tray which seems to work.

I also duplicated several "Trojan cards" and put them in the Demo Tray. After repeated use, the first card of a deck sometimes gets a little frayed around the edges, and then won't load. You can put one or more Trojan cards at the front. They don't do anything except go to the next card, but they'll take the wear and tear away from the first card of the real deck.

Bill Worthington kindly helped me with researching exactly how the 1402 "End-of-Card" and Sense Switch A interact. Bill not only knows everything, he also knows where to find it in the manuals.

I managed to break the vacuum tube we've been using as a demo prop. I've been awarded "Klutz of the Day" for that. I found two smaller vacuum tubes which will probably suffice and put them in the demo box. If anybody has a (non-working OK) big vacuum tube, that would be great, since we try to show the size difference between the vacuum tube and a transistor.

Messing Up & sizes of vacuum tubes in archaic computers

Robert Garner has put a complete vacuum tube logic module (I think from an older IBM computer) in the 1401 demo box. It's very cool, but things get so busy during the demos that I'm deathly afraid I will damage this rare artifact. We'd all do well to handle it VERY carefully.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Bhushan Mohan is a skilled IBM 1401 technician who visits upon occasions.
While he was here, He helped Marc and Ken work on the CT IBM 729 #4 as well as helping
Frank to debug the German IBM 1402 card punch.
Bhushan is welcome to come back and help us whenever he back in the neighborhood.

--------------------------------------------------------------------

HI Stan,

Today I worked on 2 things:

New ribbon for Connecticut 1403

- German project

New Ribbon: I started by asking the status and the process for re-inking ribbons. First I learned no ink is put on the ribbon. Instead, the ribbon is sprayed with a liquid to bring ink in the ribbon cloth to the surface. Then the ribbon can print more pages. I learned that the guy who worked on the process passed away. We don’t seem to have the jig he created for the process or the exact recipe for the liquid. Next Robert found that we had a box of new ribbons. Stan pointed out it was no longer necessary to re-ink the ribbons. Thus a new ribbon was installed in the printer in time for the 3:00 PM demo today. The pages printed looked much better.

German project: I continued to develop the new PCwriter app. This app is in the PC and works with an app in the Arduino. On the PC, I implemented the command entry and decoding process. On the Arduino I implemented the command decoding process. In addition I put a looping structure around the app in both machines. This implements the shell for the rest of the apps implementation. The next step is to implement command execution processes in both apps. The PC app is using C++ under Microsoft Visual Studio. The process of translating portions of the existing app from C to C++ for the new app is ongoing. Since the SW is proceeding well, soon it will be time to build HW.

Best regards,

Tom

--------------------------------------------------------------------

Marc and Ken teamed up on the #4 IBM 729 tape drive on the Connecticut system.
    

Now if you want to know what they did on Wednesday, view the following video.
Because the video file is large, it is slow to start.
http://www.paddockdrayage.com/OneAtATime/MarcVideo.mp4
Now if you want to know what they did on Wednesday, view the following video.
Because the video file is large, it is slow to start.
http://www.paddockdrayage.com/OneAtATime/MarcVideo.mp4

--------------------------------------------------------------------

from Ken Shirriff, 7/16/20022

For future reference, here's how to diagnose the capstan switch problem from the indicator lights on the back of the tape drive. Either the Cap Out switch or the Cap In switch should be lit up (except while the capstans are moving). But we ended up with both lights off, indicating the capstan switch was messed up.

--------------------------------------------------------------------

Stan continued to bring the Keypunch driven by a PC back to life.

--------------------------------------------------------------------

Robert Garner helped getting things in order.

Stan

Tape problems were my own doing. Hwen I did the load/rewind, it ran off the end (was apparently already "to the right" of BOT. Then I muffed the re-threading... Even after I got it ok, I did not let it run long enough to hit the threshold for fast rewind.

Could not figure out how to keep the Mic from rotating down below my chin. Gave up and just yelled through my mask.

Did not pass artifacts through crowd. Enough problems already.

Did do Big Print for a kid who had "done it the hard way"

I feel like I'm in a spy novel and have returned to my desk to find a revolver with one cartridge, as encouragement.

OTOH, at least three people thanked me and raved about the Museum.

Again, apologies, although now I have given you several more ways to mess up the demo.

-Mike

Dear 1401 Demo Folks,

Mike very nicely did not mention that I was a strong contributor to the state of the demo today.
Mike, my apologies to you for missing being the 1401 Demo Assistant for today.

In a very partial defense,

• Lame excuse #1: I am dealing with poison oak and am not wearing socks for another week. (I didn't want to be "out of uniform" for the demo.)
• Lame excuse #2: I was researching a 1401 question for Jack Ghidelli.
• Lame excuse #3: None.

All – Just wanted to let you know that a new monitor is on order and should be replaced within the week.

Thank you!
Poppy - Sr. Manager, Museum Services

another note from Poppy Haralson, Fri July 15

The new monitor has been installed and is working.

Please let us know if you notice any issues.

Thank you,

Poppy

One of our happy visitors to the 1401 Demo Lab this afternoon came armed with her copy of 111 Places in Silicon Valley That You Must Not Miss.
It features the CHM and our 1401 Demo Lab as Place #35 on page 78, photos attached.

First published in 2015 and revised in June, 2021, here’s what it (incongruously) says about the 1401 Demo Lab: “Among the museum displays is an IBM 1401 Demo Lab, circa 1959, which lacks only a pencil-skirted secretary to bring to life.” SHUDDER.

It also reports on the CHM’s Babbage Difference Engine #2, “a steampunk masterpiece of cogs and levers.” OUCH.

Nice to have the publicity(!), but its CHM entry is shrieking for an update.

— Robert

p.s. About the Author on Amazon: "Floriana Petersen was born in Slovenia, where she studied Art History at University of Ljubljana. In 1986 she moved to San Francisco, where she finds illumination as an interior designer, art consultant, author, and photographer. Her interior design projects were published in numerous books and magazines (www.florianainteriors.com).”
    

We ran on CT which generally ran OK except that we got a few sporadic READ CHECK errors on the 1402. Reload corrected those problems. We powered up DE as a backup in case the READ CHECK problem persisted, but we didn't need to use it.

Same as Pat, we observed that the right-hand TV wall monitor has a bad display on the right 5 inch wide vertical column. Of course this doesn't affect the demos, since we turn off the TVs.

As usual, we had to try different BigPrint and Powers-of-Two decks to find ones that worked. I put a marker in the front of the good decks saying "Good 7/9". We still need to schedule a deck housecleaning, but I'm away for the next few days. Both Steve and I had to leave, so we didn't do any post-demo mini-demos today.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

We ran on DE, which performed well. After the demo when we were processing BigPrints, Bill switched to CT, which also ran well.

Stan came into the lab during the demo, so we had the audience give him a hand on behalf of the entire restoration team. He bowed graciously.

Problem (for CHM A/V):
The right wall monitor has an approximately 5 inch wide vertical area on the right side where the video appears hazy.

Note: I have been present for all Wednesday demos since we restarted them. I will NOT be available for next Wednesday, 7/13, so we will need both lead and assistant for that day.

Pat

The main question from last week was why did relay R109 burn out, and why is the replacement relay very hot. We determined that R109 is very hot on all the drives, so it's presumably working as intended and IBM just likes to keep things toasty. Marc checked that the voltage was correct, -48V.

We checked the circuit breakers and found that the -7.5V circuit breaker doesn't trip and reset. It should probably be repaired at some point. While looking at this, Marc noticed that there were disconnected wires on the circuit breakers, determined that they were for the fuse light, and fixed that.

We noticed that the right capstan was stuck halfway out. Fixing this didn't help overall.

Marc made a relay extender cable so he could probe the relays during operation. He found that the relays R107 and R109 appear to be operating properly so the problem must be elsewhere.

Current behavior:
When doing a load-rewind, the tape drive motors start, but then nothing happens. The next step is supposed to be the tape take-up motor lowers the tape into the columns, followed by the head descending and the capstans coming out, but these steps don't happen.

Hitting reset, unload causes relays to change state, but the drive ends up stuck in a semi-unloaded state where it will neither load nor unload. Setting R109 manually gets it out of this state, so another unsuccessful load-rewind can be performed.

Ken

Perhaps it may be a good idea to measure the current through that relays 109, 107, and the replaced resistor that was burned out…
Then compare against a drive that does not have the problem.
There’s a possibility of a wiring error, or a short in that rat’s nest area, with the close proximity of the wires inserted in the edge connectors.

Just my $0.02 worth.

Iggy

Jack Ghiselli and I gave a demo to 49 visitors. In addition to the local people, we had visitors from Japan, Australia, and Germany. We used CT, which ran fine. The sorter and key punches also worked fine. Thanks to the restoration team.
Regards,

Stephen H. Madsen

Hi Steve,
A pleasure working with you yesterday, as always. Again, you got through the main presentation in about 35 minutes flat. You are really efficient, and I'm going to try to learn from your presentation.
Just for your information,I stayed behind to continue my project to verify object decks. As usual, we kept getting late-arrival visitors continually coming in in small groups, so I had to break off and do mini-demos for them. It was a BUSY afternoon. I counted 58 additional people during the afternoon (after our main demo).

Wow. Anyway, in between I worked on BIGPRINT decks, running VOBJ to compare them, and repairing what errors I could. I ended up with three (3) good BIGPRINT Version 16.8 decks in the demo tray. Several others I discarded because of punch misaligned cards and other non-repairable errors. I hope to start on any other BIGPRINT decks are lying around, and on Powers-Of-2, and maybe LINCOLN.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Jack,

Thanks for your steely quality control campaign!

— Robert

Status report Tuesday June 29
People who attended the CHM were:

X	Stan	Paddock	4.0
X	Tom	Szolyga	6.0
X	Ken	Shirriff	6.0
X	Marc	Verdiell	6.0

Ken Shirriff and Marc Verdiell went back to work on the number 4 tape drive on the Connecticut machione.
When they replaced the relay that was determine to be found, the tape worked for less than 50 seconds and failed.
In addition, the new relay became hotter than a two dollar pistol. (What ever that means.)

Suspect now switches is the circuitry that drives the relay.
Marc took home parts from the IBM 024 parts machine from the workshop in order to build a jumper to be able to measure the voltage and current of the relay that is failing

Next week we will again attack tape drive four.
Report from Tom Szolyga
Tom has now been able to communicate between the Arduino and an IBM PC over a single USB cable.
That is a big step forward tower communication between the German machine and an IBM PC.
................................................................................................
Liebert heat problem
It was discovered that the Liebert air conditioning system had failed in 1/2 of it's capacity.
The question was is 1/2 of the Leibert is enough for our continued use?
Stan brought in a digital thermometer and turned on the German machine and the Connecticut at the same time.
Within a few minutes, the temperature dropped two degrees and stayed low the rest of the day.
This means CHM does not have to spend $12,000 to fix the failed part of the Leibert machine.
We will continue with the standard practice of turning on the Leibert when the German machine is powered up.

Stan Paddock

Stan,

Thanks for your sensible insights and temp test today with our Liebert problem. I hadn’t realized/appreciated that it has two compressors (and evaporators).

From the Liebert manual..
http://ibm-1401.info/SL-18100_REV1_08-06.pdf
… assuming our unit is the DH/VH199A model, it’s rated at 50kW (or 50/3.5 = 14 tons).

The manual notes: "The Deluxe System/3 is designed for maximum energy efficiency. Beginning with semi-hermetic compressors, the most reliable and energy efficient compressor available, Liebert adds an A-Frame coil that can provide 60% of total capacity with only one of the two compressors operating. Highly efficient fan motors pull air through the coil, providing not only better coil coverage, but reducing fan motor horsepower requirements."

Our two running 1401s (and the 60-to-50-Hz power converter) may dissipate about 20 kW(?).
so there’s not a whole lot of margin for a demo crowd if our Liebert can only handle 30kW with one compressor disabled.
(and it might be marginal on a hot day).

Perhaps we should ask the Liebert technician for his opinion?

Nevertheless, it does seem possible that we could permanently disable the failed compressor (to disable related error messages.
However, if the 2nd compressor starts acting up, then no demo’s until fixed (and a higher bill?)

Cheers,

— Robert

Gary,

When I came in today, the temperature in the 1401 demo room was 76 degrees with the Connecticut 1401 on and the German 1401 and the Liebert turned.

I turned on the Liebert and the German 1401.

Within ten minutes, the temperature dropped two degrees.

For the rest of the afternoon including the 3:00 demonstration, the temperature stayed under the initial temperature.

It appears that the Libert single compressor test was a success.

Stan

1. BigPrint. We found the current version is 16.8, generated 3/18/2016. This identifier can be found in object cards 7-8. In the ROPE compiled object deck, there is a one-byte error in character maps. The result is that the character "D" has undesired spaces when rendered as middle- or large-size. The correction is to patch object card #98, column 28, from a "4" to an "8". Here is the printout symptom:

In the patched card #98, we added the comment "PATCH" in an unused area (column 30 ff), to remind ourselves in the future. We also ran VOBJ to verify one other copy of BigPrint. Another copy of BigPrint had so many errors we trashed it.

2. Powers-Of-2. We found our demo deck had one card out of sequence. Although this was not a fatal error, we moved the out-of-place card into correct sequence.

Tomorrow (Thursday 6/30) afternoon Poppy has scheduled 100 high school students to visit, and we will give them a 1401 demo. If we have extra time, we will try to verify some additional demo decks.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Jack,

You’re genuinely disciplined in the IBM way. :)

We need to THINK about a bonus/salary raise! :))

— Robert

I came in yesterday and punched some ROPE object decks which had been waiting on the 1402. One is the VOBJ verifier to help check if our demo decks have any problems. I punched its object deck and rant it, and sure enough, it showed some minor errors in both our demo-copy BigPrint and Powers-Of-2 decks (but they run).

The Wednesday 3:00 demo was so popular it ran until almost 5:00, so we didn't have much time. When we get more time, we'll check all the copies of all the demo decks.

Thanks again to the Restoration Team.

--Jack Ghiselli - jghiselli@sbcglobal.net, Cell 408-839-1051

From: Ken Shirriff
Marc and I looked at the CT tape drive problems today.

Last week we found an exploded resistor-capacitor module RC108 on tape drive #4 and Marc removed it with great difficulty:
Marc tested it on his fancy HP RLC machine and surprisingly it turned out to work just fine! So we took a closer look at latching relay R109 next to it:

As you can see, the relay coil shorted out. Apparently the heat from this damaged the case of the RC module next to it.

I found three replacement latching relays in the workshop. One looked like it had been underwater (extensive rust), one had a bent contact that wasn't closing (not the contact wire that moves, but the U-shaped fixed part was bent), and one had some dirty contacts. Marc is cleaning up the contacts and we'll replace the relay next time.

Second tape drive issue.

A few weeks ago, Frank and Stan noticed that the CT tape drives gave errors almost continuously when operated from the TAU control panel.
I looked at the bit signals on the CT machine and compared them with the DE machine.

On the DE machine, the signals from the tape drive are 8 volts peak-to-peak as they should be. On the CT machine, the levels were all over the place. Here's a look at tape signals on the DE machine:

The yellow line is the raw signal from the tape drive, 8 volts peak-to-peak.
The cyan line shows the signal after rectification, so it has twice as many peaks.
The pink line shows the signal after differentiation, producing spikes.
Finally, the blue line shows the data as stored in the TAU bit latch.

On CT#1, when all bits were supposed to be set, bits 2 and C were missing from the A register.
That is, the TAU didn't read these bits.

Here's how bits 1 2 4 and 8 look as received from CT drive 1. These should all look like the yellow line above.

Note that bit 2 (cyan) is about 3 volts peak-to-peak, much lower than the others, which would explain why it doesn't get read.

The others are 6 volts instead of 8, so they are significantly lower than they should be, but the TAU still mostly reads them. I didn't look at bit C, but it's probably low like bit 2.
Probably the amplifiers need to be adjusted, although it could be a problem with writing instead.

Drive #2 is even worse, with all the signals around 2 volts peak-to-peak.

Drive #3 has signals around 5 volts peak-to-peak.

I didn't test drive #4 because of the relay problems.

Since the drives all have different issues, I think the problem is with the drives, not with the termination.
So it looks like the CT tape drives all need some adjustment before they will read data reliably.

Ken
--------

From Marc Verdiell

And while Ken figured out the bad relay and the bad tape reads, I replaced the cracked RC module with one that looked good (although, as Ken pointed out, the cracked one probably still works, it appears to be just cosmetic damage).

I think we should reverse engineer the cracked module construction for the benefit of science, it looks like a highly interesting and advanced construction, maybe using thin film ceramics.

I then proceeded to reconnect all the backplane wires at the right places, those that I removed on purpose and had marked, and those that had decided to remove themselves on their own will without being marked.

It’s very hard to access and see through the thick mess of entangled wires in the backplane, and I was proceeding quite carefully to avoid introducing wiring mistakes, so that took me all day.

All the wires are back in, hopefully on the correct pins.
We should be able to just plug in a new cleaned-up relay in location 109 next week and see if we corrected the problem.
Or if we created a new exciting one…

Marc

Frank King has a grandson Mason King who came in today to see what his grand father does at the CHM.
Mason was a great help with today's work on the punch.

Connecticut IBM 1402 Card Punch

For several weeks, we have tried to fix the card registration of the cards punched on the Connecticut machine.
We have tried cleaning and adjusting this and that.
We have three books on maintaining the 1402 card punch.
None of these books seem to match our punch.
One of the books seemed to be close to our punch.
It described an adjustment that has a range of +- one degree.
When the guys checked, it seemed the adjustment was out of range.
Frank, Dale and Mason adjusted the setting and it fixed the problem!!
With the knowledge from fixing the Connecticut card punch, we think it is time to fix the card punch on the German card punch next punch.

Leibert room PC to IBM 029 keypunch

Stan is continuing to change the software to support the new hardware configuration.
Several weeks to finish the job.

Stan

------------ This is an addition from Frank King in reference today's work. ------------

We cleaned and adjusted the timing on the grip and release, of the secondary alignment for the card to be punched.
We reproduced a new big print card deck and left it on the reader.
I hope this fixed the problems with the punch unit.
You guys can try it out and let me know your results.

Thanks for all you do.
Frank

Present were:

Dale Jelsema
Frank King
Mason King
Stan Paddock

He found that there is a relay in the third IBM 729 on the Connecticut machine that was not playing along with the band.
Ken took the SMS card that drove the relay home and checked the driver circuitry that drove the relay and found the transistor that drove the relay was blown.

Ken replaced the SMS card at the CHM and tried it again.
he relay stilled did not work.
Not only that, the same transistor as before was blown.

This narrowed the problem down to the relay or the arc suppression diode across the relay coil.

Failure of either one of these is very rare.
The arc suppression diode had shorted so that when the transistor wanted to activated the relay, the shorted diode blew the transistor.

In the shop, we have multiple copies of the transistor so both blown transistors were replaced.
Marc found a generic diode that had a higher PIV and current rating than the original diode.
With a little soldering, the tape drive was put back together and tested.
Everything on drive three is AOK.

Stan

Today I {Tom} worked on the SW to communicate between the PC and the Arduino.
Making progress.

Stan, here's Ken's Wednesday status explaining the RC module problem.

I investigated the tape drive CT#4 more today and it needs a new RC 108 module. This resistor-capacitor module snubs the relay coil. As you can see in the photo, it has self-destructed. (This is the module to the right of relay 107.)

Click to enlarge

To summarize what I've found:
Latching relay 109 closes to indicate an unloaded state. (It latches to store this state across power off.)
When this relay opens, it turns on the blower relay DP4.
When the blower vacuum switch closes, it turns on the main run relay R1.

The observed problem is that when the drive is powered on, the blower turns on and then the drive starts running, even though it is unloaded. So the problem is in the R109, DP4 path. I figured one of these relays might be faulty. However, the bad resistor-capacitor module R108 is across the coil of R109, so if it's messed up, it would explain the problem.

I need help to replace the RC module though: Do we have any of these 330 ohm .1 mfd modules? The module is hard to replace; it has taper pins plugged into it, and of course they are behind a bunch of wiring cables. So I'll need a hand with the wiring.

Click to enlarge

There's nobody else in today, so we can work on this next week.

Also, about 30 people came through the lab and I explained the computers.
The computers weren't powered up, so I couldn't do demos apart from the manual punch

We had apparently used up almost all the non-rechargeable AA batteries for the microphones, so I brought in a couple additional packs. We should have enough for several months now.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

1. The third tape on the Connecticut machine was partially loaded and the tape was cut.
      Ken took the reel down, cut the damage portion of the tape off and added a new beginning-of-tape on the tape.
2. We configured the first tape drives as 1,2,3 and ran them from the TAU and got errors from each tape.
      Ken said Marc was working with these tapes and the configuration with the terminator and may know what is going on.
3. Tape 4 was know to be out of operation.
      What Ken discovered is that when the tape is powered up, it goes into a status of 50% up and 50% down.
      It is not obvious what is going on.
       Ken took home books on the tape drive to learn what make the tape work.
4. Frank and Stan checked out the card punch on the Connecticut system.
      Last week we pulled the punch unit, Cleaned every thing and put it back together.
      We punched some cards and discovered we had not fixed the problem.
       We also noticed that a pair of lower bearing are very worn.
      We will try to remove the roller shaft and get to the bearings.

Gary, Dennis, Poppy, et al,

Per Jack Ghiselli's May 28th email below, the Liebert in the 1401 demo lab is in need of service.
I understand that a Liebert field engineer checked it out a couple of weeks ago and may have concluded that one of the (two) compressors was faulty.

Any news on the repair status? Or plan for getting it repaired?

Thanks(!),

— Robert

p.s. Someone had tuned Off the main On/Off lever switch. I turned it back on for this afternoon’s demo.
When both on, the 1401 units and the 60-to-50-Hz power converter combined can dissipate up to 25kW of heat.
If not removed, it can get too warm during the 1401 demos and maintenance sessions.

If I remember correctly, a technician came last week. One of the two systems was out of refrigerant. It must have a leak. The refrigerant was replenished and the system was repressurized, but that is a temporary repair. The technician recommended that a proper leak detection should be made in a subsequent visit and the leaky part replaced. Not sure who is in charge of that at the Museum (facilities?).

Marc

Hello All
As of right now Facilities is waiting on repair proposal from ACCO.
We’ll keep everyone posted on this.

Thank you,
Luis,

I suspect the nefarious Amazing Restoration Team is having fun teasing us demo docents. When I powered up CT, at first the 1402 wouldn't read cards, although I tried several decks. Finally opened up the covers and lo to my surprise found a greasy paper towel in the read rollers. I bet you guys have a camera somewhere and were just laughing at us. OK, I have put the greasy paper towel SOMEWHERE in the maintenance area -- you find it! After that, all hardware worked perfectly -- the CT, its first two 079 tape drives, all the 026 Keypunches, and the 083 Sorter. Anyway, if you guys fix the CT 1402 punch, all will be forgiven.

We had a lot of visitors -- 42 for the main demo, and 36 others who wandered by later in small groups for mini-demos. We continue to get quite a few international visitors, today from Australia (Melbourne), India, Kazakhstan (Almaty), Switzerland (Zurich), and Uruguay. With only one docent, the after-demo BigPrints and especially the mini-demos for later groups went slowly. We try to shut down after the main demo, but it's really hard to turn away a visitor who's traveled a long way, with only today to see things. So mini-demos went on until 2:00 PM.

I had to remind a few visitors that the CHM is requiring masks for 1401 demos. The front desk has extras.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Well, Ed, there was GREASE on that towel. We demo docents mostly just stand around looking beautiful. I had to go wash my hands. Yuck!

Ken Shirriff is well known for reverse engineering printed circuits.
He found that there is a relay in the third IBM 729 on the Connecticut machine that was not playing along with the band.
Ken took the SMS card that drove the relay home and checked the driver circuitry that drove the relay and found the transistor that drove the relay was blown.

Ken replaced the SMS card at the CHM and tried it again.
The relay stilled did not work.
Not only that, the same transistor as before was blown.

This narrowed the problem down to the relay or the arc suppression diode across the relay coil.

Failure of either one of these is very rare.
The arc suppression diode had shorted so that when the transistor wanted to activated the relay, the shorted diode blew the transistor.

In the shop, we have multiple copies of the transistor so both blown transistors were replaced.
Marc found a generic diode that had a higher PIV and current rating than the original diode.
With a little soldering, the tape drive was put back together and tested.
Everything on drive three is AOK.

Having three operation IBM 729 tape drives on one 1401 computer is pretty good.

Next week we will attack tape drive four.

People who attended the CHM were:

Frank	King	6.0
Stan	Paddock	6.0
Tom	Szoolyga	6.0
Ken	Shirriff	6.0
Marc	Verdiell	5.0
Robert	Garner	2.0

Report from Tom Szolyga Today I worked on the SW to communicate between the PC and the Arduino. Making progress.

Today, Steve Madsen and I gave the 1401 demo to 43 people, and mini demos to 10 additional people who wandered in later. There were visitors from Connecticut, whom we told about the history of the CT machine, and two separate families from Germany (Bremen and Hamburg) whom we told about the DE machine (they liked the internal 1403 labels in German). Another group came from India (Bangalore), and we showed them the photo of the (non-functional) IBM 1401 on display in Bangalore, which they now intend to go visit. There were also international visitors from Russia (two different people) and Switzerland (Zurich). The museum seems to be attracting lots of overseas visitors.

A BIG thanks to Steve, who signed up to assist at the last minute when he noticed nobody else had. Yay, Steve! We finished the demo in 40 minutes time, and got all the after-demo BigPrints done and handed out to this large group by noon. We used CT. All the hardware worked well, including all 029 Keypunches and the 083 Sorter. On the 083, we are using Pat Buder's suggestion to alternate between columns 74 and 75 on the Sort Deck, which seems to result in a pleasing Sort demo. Thanks to the Restoration Team's work last Wednesday, two 729 Tape Drives on CT were working so we could demo tapes using the TAU.

As a reminder, the CHM is asking 1401 demonstrators to require masks on all visitors and demonstrators in the 1401 lab.

Stan: I forgetfully left my USB thumb drive in your PC hooked to CT. Please don't throw it out, and I'll get it next time I come in. PCWRITE function 2 works great for printing ROPE listings on 14x11 paper.

Ken worked 6 hours
I was the only one at the lab today, so I studied the documentation for the CT drive that isn't loading properly. I didn't power up the system since I figured that poking around in the tape drive by myself was potentially hazardous.

Summary: I think the problem is that the capstan motor isn't starting. I hope to probe the capstan motor logic (TU.9.40.1) tomorrow.

Details (mostly for my reference, but in case anyone wants more):

To review, the symptoms when loading a tape on this drive:

1. The tape down motor goes on for a few seconds and stops. This turns the worm gear that rotates the brake clutches, moving the tape slightly into the columns. This behavior is correct.
2. The head up motor moves the head down (down, not up, because R7 motor reverse is active). The head up switch opens and the head down switch closes as expected. However, the motor doesn't stop, which is wrong.
3. The capstans don't come out, and the right clutch doesn't spin the tape into the column. This is also wrong.

I think that figuring out why the capstan motor doesn't start is the key, since the clutch is activated by the capstans. The capstan logic is TU.9.20.1:

As far as why the head down motor doesn't stop, I've puzzled over the logic for a long time. My conclusion is that the logic doesn't match the written description in the manual:

Supposedly the head down switch stops the motor, but as far as I can tell, this is not how the logic is implemented and not how this 729 should behave. My guess is that this 729 is a bit unusual (since it's the only one with this circuitry in the lab). Specifically, on TU.09.35.1, unload gate goes low, which blocks the signal from head down and then ld gate, so the motor stop signal is blocked. All the signals here appear "correct". As far as I can tell, the circuit just doesn't match the description, and the motor is not stopped by the head down switch.

Thus, fixing the capstans should make everything else work.

Ken

Project Report: Today I worked on the SW to communicate between the PC and the Arduino. I have converted the PCWriter app to Visual C++ and Visual Studio 22. It compiles and runs on Windows 10 or 11. So far it takes commands from the user and opens/reads and writes files. Next step is sending the files to the Arduino. I am investigating two ways to do that. One way is by doing IN or OUT instructions to the I/O port. The second way is by using Windows I/O functions calls. Doing I/O instructions in a C user application program to a Serial port mapped through a USB port is dodgy because Windows is not a real time system. I am thinking that using Windows function calls is a more definite, easier to read approach. Unfortunately it takes more time and effort to create.

Report from Frank King

Ken and I worked on CT tape drive # 3. The head down switch seems to be operating properly but the circuit that starts the capstan motors doesn’t seem to be working. If we manually pick relay 3, the capstan motors start but the circuit doesn’t pick R 3 or R to 8 like it is suppose to. Ken is going to take the card home to see if there are bad transistors.

and Stan

I duplicated Big Print deck using CT and it ran ok except for one reader check. So, we should make the alignment of the punch a priority next Tuesday.

Mark and a buddy from Paris (Antoin Bercuvri), I think, continued body work on the covers for the tape drives. Looks like they knew what they were doing.
They fit for the first time. :-)

Robert showed up for a few minutes at lunch and then came by the 1401 area for a short time.

We had a visit from Kate McGregor.
She stopped by on her way from Alaska.
What a wonderful person.
The Museum was lucky to find her.
Too bad she has to work remotely.

Stan

Attached are four photos of Marc & Ken working on the ailing CT 729s with Marc's guest Antoine Bercovici visiting from Paris yesterday!
It was fun showing off/sharing the 1401, RAMAC, and Revolution exhibits with Antoine.

In his spare time, Antoine has beautifully micro-photographed hundreds of chips (from his collection of thousands):
https://zeptobars.com/en/
https://twitter.com/Siliconinsid
His "day job" is researching paleolandscapes, paleobotany, and sedimentology:
http://www.paleoserver.com/aberco/site/homepage.html
(I dare say that integrated circuits could be viewed as an instance of small-scale sedimentology! :))

Adding my own shots of the day, this working 1401 display is some of the most unique vintage computer exhibit, having all the sound and the smell of the vintage equipment filling the room.

I must say that Zeptobars is not me, but https://twitter.com/Siliconinsid as well as https://www.instagram.com/siliconinsider/ is!

And a bit of shameless promotion for our work in Colorado, elucidating how life recovered in the 1 million year following the dinosaur killing asteroid impact: https://www.pbs.org/wgbh/nova/video/rise-of-the-mammals/

Cheers!

Dr. Antoine D. Bercovici
Research Associate (Paleobotany and sedimentology)
Department of Paleobiology, NMNH Smithsonian Institution
10th Street and Constitution Ave. NW, Washington, DC 20560-0121
http://www.paleoserver.com/aberco/

I gave the 1401 demo on Saturday 5/21. Nobody signed up as Assistant. There were 32 visitors for the main demo, and 19 people who wandered in later for mini-demos. There were international visitors from Australia (Sydney), Canada (Vancouver), Germany (Hamburg), Poland (Warsaw), Russia, and Switzerland (Zurich). A very lively group, with lots of questions. I used CT, which worked perfectly. The Amazing Restoration Team had even got one CT tape drive working, so there was no need to use DE for the tape demo. All 029 Keypunches and the 083 Sorter worked perfectly.

I put a good BigPrint deck and a good Powers-Of-Two deck at the front of the metal Demo Cart tray, and recommend you use these. There are several other copies which don't work, and a quick inspection showed at least one was missing cards. I'm looking forward to a working 1402 punch so we can punch a new VOBJ object deck, run it to see what the problems with the various Demo decks are, and make all copies good.

The main demo, including 083 Sorter, took only 37 minutes, which is about the desired duration. Without an Assistant, the multiple after-demo BigPrints took longer than usual. One minor good news item: I discovered our missing third demo vial of cores at the bottom of the cardboard carton on the Demo Cart, so it didn't get stolen after all. Thank you, Esteemed Honest Visitors. "Trust but Verify", as Ronald Reagan used to say, quoting the old Russian proverb, “doveryai no proveryai”.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

On Wednesday, May 18, Pat Buder and I conducted the 1401 demo for 14 museum visitors. They were joined about 5 minutes after the demo started by a dozen highschoolers who were enjoying a field trip. along with the 14 visitors was a couple from Italy.

We had a problem finding a working BIG PRINT deck(I thought there were about 3 copies in the program tray.and borrowed Jack Ghidelli's Thanks Jack!

The visitor from Bulgaria had worked back in 1968 on punch card computers built in the Soviet Union, which he said were copies of IBM 360s.

When we came in, there was a multi-card jam in the 083 Sorter. I had missed seeing Pat Buder's report from Wednesday about this, but luckily we were early, so had time to clear the jam and get the 083 running again. While testing the 083, I noticed that cards were sorting into the correct 0 to 9 pockets, not "one off" as in the past. The 083 directed some cards to the REJECT stacker, although the cards seemed to have good punches. I suspect some of these had been punched sightly mis-aligned, so I'm not sure whether our past sorting problem is actually an 083 problem or a 1402 punch alignment problem. I agree with Pat Buder's suggestion that after the 1402 Punch is fixed we should punch a new demo Sort Deck.

We ran the demo on CT, but since none of its tapes are working yet, we demonstrated 729 Tapes on DE, using the TAU. Everything ran beautifully. Thank you again, Restoration Team. We got the demo finished in 45 minutes, which is slightly long. Still working to shorten it up.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

I put the shaft back in the machine [CT Tape], re-pinned the hub, and re-mounted the brushes (always a challenging operation, this last one). The tape drive should be good to test next week after I re-tension the main belts.

The DE tape drives fail to write bits without hanging after a few seconds. The Disc light is on but I think it should be if it hangs

I had three groups of young adults about 12-14 years old that punched cards. Once they got the hang of it, they punched like pros. All that wanted a Big Print so I ran it for them. First group was about 10 -12, the second group about 20 - 25 the third group was 10 - 12.

The 1401 group had lunch together.

Tom sounded like he was making progress on his German project.

Mark found a lot of new things about the tape clutches and seems about ready to install the rebuilt braking system into the tape drive.

Ken and I worked on the CT # 3 729 that had the head down problem. It still will not dump tape in the right side when attempting to load.

I rebuilt the CT tape brake clutch: pressed new bearings in, put new felt seals in (hopefully correct size and correct place this time), refilled with 29g of special magic iron powder, tested that it worked at the required current, then reassembled the main shaft with all 3 clutches.

I know that Tom continued to work on his serial interface over these last two weeks. He is making it quite user friendly by adding a nice color LCD screen.

Frank tested the machines and started working on the CT punch, which Jack Ghiselli had reported defective.

Ken worked on trying to figure out why the CT tape next to mine gets stuck in its state machine logic when trying to load a tape, and made some diagnostic progress. It is the only Model II tape with NOR logic that we have, which means we can’t compare its devilish load logic it with another working one, which is very annoying. Ken tried to explain it to me, and it sounded very complicated.

In addition, Google Gobble, the local wild turkey, was waiting for me at the side door when I went to get my lunch. He looked annoyed and suspicious, and let out a loud gobble. Incidentally, lunch was a turkey sandwich, so he had good reasons to be annoyed and suspicious.

We used the CT system for most of the demo, but since its tapes don't work we used the DE TAU and the one working DE tape drive. All three keypunches and the 083 sorter worked fine.

Still hoping for a working 1402 punch when the Restoration Team gets time.

Weekly 1401 demos on Wednesdays begin 5/11.

--Jack Ghiselli jghiselli@sbcglobal.net, Cell 408-839-1051

Subject: IBM 729 tape head repaired

I think the tape head is repaired. I extracted the two screws. I made a locating punch in the center of the screw stub, drilled a small hole in the middle, then used the screw extractor, both came (almost) right out.

The erase head plate did fit very snugly in its former footprint, so I just put fresh liquid cyanoacrylate and it locked back right in there. Also the erase head itself has a locating peg, so when I screwed it back on, it went right back to where it was. It should have retained the original alignment, which seems non critical anyhow, it’s pretty far from the tape. Ken believes it’s not used in our tape models anyhow.

I think we should be all good to go and can reuse this head if we wanted to. Plus it’s all cleaned up now.

Screws extracted:	Holes nice and clear	Erase head with the missing plate
Erase head with the plate back on:	Went back into the perfect place:	It’s all fixed (I think):

Marc

We ran programs from both systems. Everything worked with the exception of the tapes and the German punch. Only 1 of the tapes works on CT so, I would suggest for demoing the tapes, use the TAU panel. All 3 work on the German machine from the TAU using go forward and go backward.

One of our visitors worked in 1957 with Honeywell on early magnetic tape drives. In addition to visitors from the USA, we had visitors from Germany and Italy, pushing our language skills.

The CT 1402 Card Reader/Punch was inoperative. There were cards left in the reader throat, the READER STOP light was on, and we were unable to perform a Non-Process Run-out on either the Reader or the Punch. So, we used DE. On DE, one 729 Tape Drive was marked as Out of Operation, so we used the right-most two drives. Using the Tape Exerciser (Ron 2.1) program, we were able to run the right-most tape, but the next to the left only did one write cycle and then stopped. So, we ran the demo using the TAU, and both drives worked OK. We didn't have time to diagnose the tape issue further. We ran BigPrint and Powers of Two for the demo, and both ran OK. All three 026 Keypunches and the 083 Sorter worked OK. Our sort deck is getting a little ratty, but with both 1402 Punch units down, we couldn't punch a new one. We found the Tape Exerciser (Ron 2.1) deck in the Demo Tray was missing its last 3 cards, so we duplicated new ones from another deck on the Keypunch.