Schedule September 2009
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Wed September 2 - General, Thurs September 3 - Tape Team, Wed September 9 - General, Thurs September 10 - Tape Team, Sat September 12 - 2nd Sat Wed September 16 - General, Thurs September 17 - Tape Team, Wed September 23 - General, Thurs September 24 - Tape Team, Sat September 26 - 4th Sat Wed September 30 - General,
Wed September 02 - general
- Present were: Ron Williams, Bob Erickson, Bill Flora, Frank King, Joe Preston, Don Luke, Stan Paddock, Bill Newman, Ron Crane, George Ahearn, Ed Thelen, Robert Garner. We had about 25 guests total.
Bill Flora, who knows no fear, decided to get the margining power supply (located in the 1402) fixed for the CT 1401. Since I am the "power supply guy" I got involved, things were not going well (the remote controls?) so Bill Newman and Ron Williams got dragged into the fray - and we all learned more about voltage margining. But not enough because the margining system is not working yet - This oil filled 6 microfarad 330 v ac capacitor blew some months ago and has long since been replaced. It was used in the circuit of the ferroresonant voltage regulating transformer.
This is the front of the Margin Remote Control in the CT1401. Note you can either increase (boost) or decrease (buck) the controlled power supply voltage. The back side of the panel to the left This telephone type plug selects which marginal voltage to adjust with the Remote Control. The top socket in the red bakelite is "REST", does nothing.
- Bob Erickson worked on aligning the 513 reproducing punch after taking it apart to get the oil pump fixed - did I mention that Stan Paddock said that he fixes oil pumps of antique cars with 5 mill teflon sheets- we are trying this fix here.
In any case, Bob got to counting funny, like he didn't have no schoolin or nothin -
- 12, 11, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 14, then back to 12 again !!
He explained that the marks on the main timing gear are in the same order as the card rows going through the machine - starting at the 12 edge first, and that the 13 and 14 are the spacings between the rows of adjacent cards going through the machine.
and there are two clutches that have to lock up, one at 13.5 (five teeth after 13) and 14.1 (one tooth after 14)
Ya know, those people that designed those machines had to be pretty clever!!
- Complicated - OH MY
- This is embarrasing, the folks were busy, Joe Preston and Don Luke polishing the 729 mag tape hubs - standing tall - and there were many activities I missed completely :-((
Stan brought in some JAVA experts who he hopes to con into making some enhancements to Ron Mak's ROPE. Ron Crane brought in some friends
And George Ahearn had some guest from ProofPoint Inc.
- What a fun day :-))
Thursday September 03 - Tape Team
Wednesday September 9 - General
- Present were: Ron Williams, Bob Erickson, Bill Flora, Frank King, Joe Preston, Glenn Lea, Stan Paddock, Bill Newman, George Ahearn, Ed Thelen, We had about 2 guests total. Robert Garner will not be present for the next two weeks - no bagels :-((
- Stan Paddock brought his brother, Milan, another car enthusiast (car nut ;-), along for the day.
Bill Worthington held his 1401 Macros class at 1:00 to a small but enthusiastic audience. :-)) The text "Autocoder (on Disk) Language Specifications IBM 1401, ... is available at bitsavers Maybe Bill W. would have preferred a little less enthusiasm ;-)) . from left, George Ahearn, Mike Albaugh, Bill Newman, Milan & Stan Paddock. unseen Ed Thelen Bill W. provided printed copies of his presentation as Power Point. .
- Bob Erickson and several others re-assembled the 513 reproducing punch, and encased the top part in its plastic covers for convenient save viewing :-))
- The Marginal Power Supply (to supply the voltage margins to help promote reliability of the 1401) is turning into a battle.
- Bill Flora and Ron Williams found that a wire connecting the power supply to the Remote was mis-connected - but that did not seem to cure the problem of last week. :-((
There were multiple, slightly different, ALDs (schematics) in the books - we finally found the one that seems to match our reality. (the expanded image is 250 K bytes)
- Bill Newmann and Ed Thelen struggled with the power supply on the bench, wiring pseudo remote wiring, and cockpit errors, and eventually got back to the original problem - popping the circuit breaker after the control pot was advanced to about 1 volt - with or without an external 2 ohm load resistor.
- To add to the confusion, popping the circuit breaker seem "normal" as seen in this manual
- About 7 PM we gave up -
- Again I must apologize for not covering activities of all the participants - I spent 2 hours in Macro Class, and struggled with the Margin Power Supply.
- Normally I keep my hands in my pockets and emulate the Pointy Haired Boss, or maybe Captain Peacock, or is it the "Young Mr. Grace" ?
Thursday September 10 - Tape Team
Saturday September 12 - 2nd Saturday
Wednesday September 16 - General
- Present were: Ron Williams, Bob Erickson, Bill Flora, Frank King, Glenn lea, Joe Preston, Don Luke, Stan Paddock, Bill Newman, George Ahearn, Jim Hunt, Ed Thelen.
- Robert Garner is on sabbatical - something about visiting WWAM principal Maurice Papo in France, and other activities. (He has been e-mailing from Rome ;-))
Jim Hunt is back from Burning Man. He said that he is browned - to me it looks like a bad sun burn. Jim says that there is more going on than the rumored lack of conventional inhibitions. He says to search on 'Big Rig Jig', 'Temple of Gravity', 'Burning Man Colossus', 'Burning Man Wave Waffle', 'Burning Man Uchronia'.
- After getting de-briefed in detail by Ed Thelen ;-)) Jim got down (or up) to fixing SMS cards again :-))
We are starting to print more on the CT 1403. Frank King is unhappy with the print quality/alignment. So - alignment time is coming -
The computer resumed normal operation after we removed the Margin Boost, and pushed most of the RESET buttons. Whew!! :-| :-)) Presumably many marginal circuits? You are supposed to be able to run system diagnostics successfully when the margins are both boosted and bucked -
More action on CT Margin Checking. Last week, we used two resistors to emulate the pot in the Remote Margin Control. The circuit breaker opened each time we tried to power up the unit. During the intervening week, Bill Newman found that you really need a pot, and it must be at 0 when applying power. Now we can boost the margin voltage, but not buck it. More study !!
- Boosting the +6 volt margin by 1 volt (up to 3 volts is allowable) caused dramatic failures - the printer went into high speed slew, and almost all the lights on the operator panel lit, including all peripheral error lights and all the register select lamps (only one on at a time is normal operation). Looked like a lamp test.
- Apparently the 1401 does not have a good single "check everything test" to run while varying the margins. Apparently a test called "Midas" was developed for the System 360 to exercize the system while margin testing. Bill Flora says that on the SAGE system, diagnostic software could actually vary the margin voltages - no human intervention required.
Glenn Lea and Bob Erickson working on the 077 collator.
Bill Newman started trying to place the output of ROPE assembler onto the pseudo tape that Bob Feretich built. The goal was to then load the pseudo tape into the 1401 and run the code :-))
- To avoid "illegal character" warnings, you must select "Pierce IBM A" encoding! Also, the 1401 loads/boots/IPLs from TAPE 1 only. The code got into the 1401 correctly !! :-))))
Len Shustek, 2nd from right, CHM Chairman of the Board, brought two friends, shown talking with Frank King.
- Len says "They are George and Barbara Keremedjiev, the proprietors of the second-best computer museum in the US, the American Computer Museum in Boseman Montana. See http://www.compustory.com/. Definitely worth a visit when you are next in the vicinity of Yellowstone."
- Joe Preston and Glenn Lea were cleaning contacts in one of the 729 tape drives. Something about contact files wearing out, something about getting the wife's emery boards, for fingernails, and for relay contacts? I think I used to hear complaints that the abrasive particles from emery boards could get stuck between contacts??? -
Bob said that working on the 1401 systems has saved him from further projects like this ;-))
In 2002, Bob Erickson made this little binary adder. No logic elements other than diodes to prevent "back currents" This is the logic of each binary digit switch This is the overall logic
Thursday September 17 - Tape Team
Wednesday September 23 - General
Thursday September 24 - Tape Team
Saturday September 26 - 4th Saturday
Wednesday September 30 - General
- Present were: Ron Williams, Frank King, Allen Palmer, Glenn Lea, Joe Preston, Don Luke, Stan Paddock, Bill Newman, Jim Hunt, Ed Thelen.
- Robert Garner is on sabbatical - something about visiting WWAM principal Maurice Papo in France, and other activities. (He has been e-mailing from Paris ;-))
Glenn Lea in a hole (in the floor) :-(( Some days are like that - Joe Preston just got out of his hole :-)) They are getting three CT 729 mod IIs connected and into a row. They have negotiated with Stan Paddock (who also works at another volunteer organization - with a good metal cutting band saw - ) to cut some larger holes to reduce the bending on the cables. (The 2 drives on this side work, the third is still rather sick.)
- We had a bit of a milestone today - first attempted/successful repair of a double wide STAR (STorage Address Register) card called ADB.
Jim Hunt brought in some more little switches to ease testing the circuits Here is the component side of the card. Note that the key prevents insertion :-)) Here is a schematic of the sick ADB card Zooming into the reported failing section. OK, getting serious !! Jim says the flip flop doesn't latch. The extra ADB card near Jim's elbow is a good one for comparison. Transistor T17 seems sick. Jim also tested T17 with the VOM. Removing T17. The black thing in Jim's left hand is a "solder sucker". You compress the spring in an air piston until it latches. Heat the solder until melting, compress the trigger and air rushes in, sucking the melted solder, freeing the component :-)) Jim said "the collector lead 'rotted off' ". Inserting a new 2N1302, a germanium replacement for the IBM 083. The black ring around the three leads reduces the chance of the metal case shorting something on the card. Soldering - I tried to get the whiffs of smoke (evaporated rosin core of the solder) but failed. All that is left is to clip off the long leads, insert the card, remarks, and defective T17 into a little plastic bag, and put all into the "Fixed Box". :-))
Left to right, Ron Williams, Frank King, Don Luke examining print quality. If you promise not to tell *anyone*, some time between last week and this week one of the plugs supplying current to the printer hammer magnets came-loose/got-removed and caused confusing symptoms. Every other odd column did not print - AND THERE WAS NO PRINT CHECK ERROR
Bill Newman watching Stan Paddock tweeking version 0.8 of ROPE. Stan is changing the JAVA controlling source file access to enhance something I didn't understand.
- Stan - if you don't document the enhancement, the "rest of us" will never know ;-))
One of the key punches became erratic. Probably time to test the tubes? Frank King is swapping tubes into a socket whose circuit is well adapted for testing tubes. Note the use of paper towel to permit "hot swapping" ;-))
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