return to main 1401 Restoration Page
go to Schedule 2005 October - December
Ron Williams replaced Grant, and further TAU progress was made. Ron says Bob F. and Grant show great promise :-))
Present - Ron Williams, Don Cull, Dave Cortese, Robert Garner, Ron Crane, Bob Feretich, Ed Thelen.
Present - Ron Williams, Robert Garner, Ron Crane, Bob Feretich, Tim Coslet, Allen Palmer, Ed Thelen.
Ron Williams got the 1401 to add two numbers with out reporting/generating an error.
This failed card was pulling down a large wired OR which forced an overflow,
which caused the B zone bit of the final character to set which generated a parity error in memory.
(If you don't understand the above sentence, call Ron Williams, not me!!) Tim had been kept busy repairing cards. Today, Ron Williams replaced his 40th bad card (above).
I have been corresponding with Jason Olson who works at Amkor in Chandler, Arizona.
He *really* wanted to see the restoration effort, so today he and Cliff Stricklany flew in from Phoenix to see our 1401.
Tim showed them the powered-off PDP-1 restoration. They took the Visible Storage tour, but the IBM-1620 was
not powered - a defect?
Tomorrow they will visit San Francisco :-) I steered them to the
Exploratorium, another hands on experience :-))
Jason and Cliff use RPG in their daily work. You could have knocked the rest of us over with a feather!! The language is still alive and well with extensions including terminal screens, sub-windows, and Internet access! Jason is looking for an old 1401 RPG deck for us. - There must be one "out there" somewhere.
Tim demoing the 026
Robert Garner greeting
No report. Your recorder was on vacation :-))
Present were Robert Garner, Grant Saviers ('till knee pained up), Robert Feretich, Ron Crane, Ed Thelen.
- 1401 Data Processing System Bulletin 1962.pdf FE Training, 2.5 megabytes
- 1401 Beschreibung.pdf FE Training? in German, 0.4 megabytes
- 1401 Diagnostic Test.pdf notebook of diagnostic tests, 1st 40 of maybe 400 pages 6.0 megabytes
Present were Ron Williams, Bill Flora, Ron Crane, Robert Feretich, Ed Thelen -
- Sorry - I was busy talking with two visitors from Germany and Xeroxing diagnostics and missed what was happening ;-))
- Ron Williams and Robert Feretich worked on the 1401 - a struggle - little (any?) progress
- Ron Crane got some replacement germaniun transistors from Halted.
- Bill Flora found a blown fuse and got the 1402 read mechanism to function (again)
- Alex Bochannek came by and verified that some German diagnostic documentation was similar to an English version we have.
Present were Allen Palmer, Robert Garner, Robert Feretich, Don Cull, Ron Crane, Frank King, Ed Thelen. Ron Williams is a juror on a murder trial :-|
Ron Feretich Debugging 1401
Present were Ron Williams, Robert Feretich, Ron Crane, Bill Flora. Report by Ron Williams
- Ron Williams and Bob Feretich got closer to why one of the 4 K character memory banks isn't accessable
- Ron Crane fixed failed SMS cards
- Bill Flora - worked on 1402 card reader - trouble with picking the read clutch -
Present were Allen Palmer, Ron Crane, Don Cull, Chuck Kantmann, Frank King, LaFarr Stuart, Grant Saviers, Ed Thelen. A major effort to locate the fuse blowing problem involving the 1403 printer hammers and the driver cards (and it was thought printer memory). A diagram 31.??.??.?? was needed and we couldn't find it in the ALDs. I was about to head for the archives when Chuck found it as an A size drawing in a manila folder - what a surprise!! Maybe we need to make a better list of documents and where to find them!! Ron Crane determined that the bias of all the printer driver transistors is way bad - full conduction - and the main 1 amp print fuses blow before the 130 individual hammer driver fuses blow (fortunately!). Some -60 volt bias is not coming back from the printer.
Allen has his 729 Mod V running in a continuous forward/rewind/forward mode - and it is *wonderful* to see that baby rewind - rated speed 2750 RPM - that baby *spins*
Ron Williams (jury duty), Bob Feretich & Ed Thelen will be on vacation.
Bob Feretich & Ed Thelen will be on vacation.
- Aug 11th - Grant reports that the Skew Tape he bought via e-bay has arrived :-))
Now in 1401 computer room :-))
Report by phone from Ron Williams. Ed Thelen was entaining himself with gout - his body didn't change - and that 2nd bag of potato chips was a killer.
Present were Allen Palmer, Frank King, Glenn Lea, Don Cull, Bob Feretich, Chuch Kantmann, Bob Erickson, Robert Garner, Ron Williams.
- Ron W., Bob E. and Bob F. got most of memory working - still known flaky address card in one 4 K bank. Working on a bug in the Z operation (Move Supress Zeros)
- Don C, Glenn L. and Chuck K. worked on 1402 parts
- Frank K. worked on the 1403 brush interlock and feels closer to the bad bias on hammer drivers
- Allen P. and ? heard worrysome noises in a 729 clutch -
- Robert G. presided and supplied bagles
Present were Allen Palmer, Frank King, Glenn Lea, Bill Flora, Bob Feretich, Chuch Kantmann, Bob Erickson, Ron Williams, Ed Thelen.
Bob Feretich will be coming in Thursdays to work on the 1401 debugging. The added effort and time should find more bad boards faster.
- Allen Palmer and Glenn Lea worked to remove a noisy magnetic drive clutch from the 729 mod V being restored.
Removal of the section closest to the reel turned into a real unfinished problem!
- Bob Erickson and Ed Thelen went C & S Supply in Santa Clara to get a new belt for the 077 collator. 76 inches is a little tight, 77 inches a little loose
- Bill Flora and Chuck Kantmann worked on the 1402 timing - the inability to get the dynamic timer circuit to work is getting really annoying.
Ron Crane - we need help
- Frank King got the 1403 printer to slew to channel 1 :-))
- Bob Feretich found a regulator (drops 30 volts to 12 volts) in the 1406 was overvoltage and unadjustable.
Replaced the drive transistor to no effect, replaced the big pass 022 transistor (from John Falk) and solved the problem.
- Ron Williams worked on the 1401. After hours Bob and Ed chased an extended memory addressing problem.
Addresses ending in 9 in the 2&3 hundreds range in 8,000 through 11,000 read no bits and bad parity.
Swapping what we thought were the decoder/driver cards did not move the problem :-((
(Switch core matrix technology was used before suitable memory core drive transistors became available.)
dynamic timer circuit
Ron F. thinking
not memory cores
Report by phone from Ron Williams. Ron Williams and Tim Coslett were there. Ron says "A terrible day, I don't want to talk about it. Things are breaking faster than we are fixing them."
Present were Ron Williams, Bob Erickson, Glen Lea, Allen Palmer, Frank King, Ron Crane, Robert Garner, Bill Flora, Milt Thomas, Robert Feretich, Chuck Kantman, Ed Thelen. Interesting day - lets start with the revolution ;-))
So - we decided to start testing the SMS cards in the 1401 processor, with the following guide lines -
- Examine/verify the "Unit Plugging Charts", one per gate, about 32 gates?, more copies made
- Test all cards of one type per gate at a time - Ron Crane to determine how to test?
- Replace passed cards back into the same slot. - mark? record? repair history of cards, if so need serial #s?
- Have more than one testing/debugging session per week - Ron Crane started to analyze the "Unit Plugging Charts"
- All cards to be replaced into machine at the end of each session
- an open X or Y drive line in the bottom core plane of the 1406 8,000 character stack
they didn't see the exact break.
- a bad core driver transistor (open collector) - Ron replaced it.
- the parallel resistor across an X or Y drive line is 4 ohms
- the resistance of the X or Y drive line wire in the core stack is 2.5 ohms
Allen Palmer on vacation 'till 29th - Sicily & Venice :-))
Present were Chuch Kantmann, Bill Flora, Milt Thomas, Robert Feretich, Grant Saviers, Ron Williams, Frank King, Ron Crane, Bob Erickson, Ed Thelen :-)). I list people and show pictures so that wives will not suspect the worst.
The 1402 reader timing light did not get completely fixed :-((( Both lamps glow just fine statically, but one
fades in a few seconds when the disk is spun. Bill Flora and crew checked the disk slip rings, brushes, springs, ...
and gave up to do other things. Other things include the 1401 Read Card command causes a 1402 to pass a card
- whether data got transfered was not checked yet.
Ron W reports that one read card command causes the card reader to start and not stop feeding cards, some read completion signal is missing?
Grant brought in a neat Effective Series Resistance (ESR) meter for us to use
in electrolytic capacitor checking, and also the 729 tape drive clutch
that he was working on. He says obtaining replacement sealed bearings for the tape drive clutch is
likely to be a major challenge -
Well - the 1403 carriage control works with the old carriage tape
- but not with the one we just punched ??? Ah - Ron says our carriage tape punch has different registration
than the one that punched the German carriage. A tweek of the brush assembly makes the
newly punched tapes work and the old German ones fail - lets go with what we can produce :-))
The 1401 can successfully command the printer to skip and space - I suppose you want it to print too? ??
The old power wiring in the 077 collator is pretty much crumbling - Bob Erickson is replacing it.
bad picture :-((
The 1401 processor guys get all the glory (and pressure) - and no picture this time.
However, Ron W reports that the Move Zero Suppress, which is really an edit command, works :-))
and command chaining works :-))
Ron Crane calculated that if some transformer taps got changed, the Pacific Power amplifiers
would run closer to "rail-to-rail" giving improved conversion efficiency, saving power.
Here he is, deep into the guts of the Pacific Power converter :-((
He was correct, saved 2.1 kilowatts with the load of the 1401 & 1406 :-))
Ron Crane also measured the power going into the Liebert air conditioner, used
to cool this room - mostly to cool the
Museum's UPS (Uninterruptable Power System) and occasionally "our" 1401 system.
(We are under strict orders to leave the Liebert running when we leave!!)
With one of the two compressors going
(it goes all the time) and re-heat to control the humidity (seemingly all the time)
This is 460 volts, the three phases average 40 amps each. Here he is examining the power factor (just about 1.0).
Ron calculates that this unit - if running this way all year - costs the museum
about $35,000 in electric power. :-|
Report from Grant Saviers :-))
Bob Feretich and I got all the counters working in the TAU [Tape Adaptor Unit] ... . 3
bad TAU modules total Wed & Thurs. We are finding many ALD errors (or
we haven't figured out how IBM names the card gates (swing out frames),
although finding a single flip flop module split onto two gates in the
prints does not appear to be our error :-( ).
We are also missing some module schematics, 2 or 3 I think out of the 10 or so we looked for. Are there other documents sources to explore to remedye these problems?
Present were Milt Thomas, Frank King, Bill Flora, Bob Feretich, Ed Thelen, Bob Erickson, Ron Williams,
Grant Saviers, Chuck Kantmann, Ron Crane, Don Cull. Frankly, I arrived late, and got caught up in Ron Crane's study of the
environment of the 1401 room. Apparently someone has turned off the re-heat part of the humidity control, which
will reduce the expense of cooling the museum's UPS system to maybe $23,000 a year. :-)) By the time we got
back from visiting with museum people, the rest of the workers had gone home and I don't know of progress.
Attendee list from Robert Garner - Bob F, Ron W, Bill F, Grant, Frank, Chuck, Ron C, Ed T., Robert G.
Here is an overview/index of ALDs (Automated Logic Diagrams)
Allen Palmer is back :-))
Attendees - Ron Williams, Bob Feretich, Grant Saviers, Robert Garner, Allen Palmer, Don Cull,
Bill Flora, Glen Lea, Ed Thelen. Special guest - Len Shustek,
CHM Chairman of Board visited for a while - fortunately we were mostly behaving ;-))
Ron Williams presents this brief history of the physical restoration activities.
Bill Flora and Don Cull (and Ron Williams) got the 1402 to punch a card. Unfortunately, the card
should have been blank - something about punch bails hanging up - [ It turned out that several SMS cards driving
the punch magnets were defective and hung in the ON state. Replacing the cards permitted punching blank cards.
The next test, later, will be to try to punch holes in all of the columns. ;-)) ]
Paul Pierce of Portland, OR very kindly sent one of his 729 tape cables so that Ron Feretich, Ron Crane,
and Grant Saviers can make a 729 tape simulator to help test the TAU (Tape Adaptor Unit) in the 1401 computer box.
This image shows the cable end minus the exterior metal housing. What you are looking at weighs more than a current lap top.
Ron Williams replaced Grant, and further TAU progress was made. Ron says Bob F. and Grant show great promise :-))