Schedule May 2008

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Contents:

Mon May 05 - Connecticut 1401 arrived, Wed May 07 - cabling, power supplies, Sat May 10 - class visit,
Wed May 14 - general,
Wed May 21 - general,
Wed May 28 - general,


Mon May 05 - Connecticut 1401 arrived,

    Background, Robert Garner and Frank King packaged and helped extract and load the CT 1401 here.

  • Most of the eventual crew of Ron Williams, Bob Erickson, Frank King, Bill Flora, Stan Paddock, Ed Thelen and Robert Garner were present when the BIG truck began to unload.
    Trying to maneuver that big truck into the loading bay OOPS - into the tree - Frank ran waving, but apparently Jeff was watching the other side Plan B, got the truck turned around, trying from the other side.
    Yeah - now lots of wiggling sideways to hit the door opening - squarely Yeah - lookin good - will the "belly box" clear the hump in the center??? It just barely touched - WHEW -
    Now to connect the truck with the loading dock - Jeff the driver is in the blue shirt - The riggers/movers (down and at the switch) are taking over. CPU, with cables on top. Frank, squatting, checking the packing and wheel, Jeff the driver on right.

    Unloading the BIG truck
    Frank checking if the stuck wheel would now rotate, it would :-)) The Connecticut 1401 in its new home. Another printer, crossing that tooth jarring, shock testing steel mat
    And the 1402 reader-punch is unveiled :-)) Not a scratch or dent :-)) Great Move! Time to sign off !! Jeff the van driver with Robert Garner. IBM is footing the moving bill :-))

    Moving other things from the loading dock to Allison's "staging area" - documents, spare SMS cards, extras
    Off the truck, into "InVisible" Storage A-Rollin along - a box of spare cables, and a box of spare SMS cards Don't we have a lovely environment?
    Off the dollies, onto pallets, and checking what's in 'em Towards the end of a long exciting day, opening, unpacking, deciding, grouping, ...

    And, back in the 1401 restoration area -
    Bill Flora and Stan Paddock examining a hinge that has been held on with wire for years "Watch out, those cables are HEAVY". - the other ended are wired into the 1401 - Unveiled at last, not a mark :-))
    Gary Matsushita signed off on the riggers, here standing by the Babbage exhibit Stan, Bill and me moved the old 1401 one square north, easiest just to cut the top brace, to move those hard wired cables - Another view, the strap around the CPU and lifts keeps the lifts from kicking out
    The 1406 with 12K characters of memory, and CPU w cables Six CT 729 tape drives, w German 729 An overview of the 1401 Restoration Room as we leave :-))


Wed May 7 - cabling, power supplies

  • Present were Ron Williams, Frank King, Bill Flora, Glenn Lea, Joe Preston, Stan Paddock, Ed Thelen and Robert Garner

  • Ed Thelen got right to work on checking the +60 volt power supply in the 1402 CardReader/Punch that drives, believe it or not, the print hammers in the 1403 printer via the printer controller/drivers in the 1401 CPU. Indeed :-)) Presumably the system has not been turned on for 13 years, maybe a marginal time maybe requiring reforming, especially in this note
    Ed likes to be near the critical path, to stay hired, but works hard to keep off the critical path, to sleep easily and have fun ;-))
    The 26 3500 ufd 70 working volt capacitors in the other 1402 were wired together. Here, each capacitor was connected in parallel by connective plates Both plates removed, exposing isolated capacitators, ideal for testing. I slowly (30 seconds) raised the voltage on each capacitor to 60 volts, no excessive current, no reforming noted :-)) Parallel resistance seemed OK for all.
    Here is Ed Thelen and Robert Feretich behind the CT 1402. Ed ramping up the voltage to each capacitor and watching discharge through the meter, Robert figuring how to use a use a more complete tester.
    Robert Feretich is an electronics type (as well as programmer) and showed interest in further testing. Here he is with an electronic capacitance tester All capacitors were at least 20% over spec (good). And leakage seemed OK. And taking notes while using an Effective Series Resistance tester :-)) OH YES, we need to buy a set of log books for the Connecticut system !! maybe 10 -

  • When we left the floor tiles after removal of the west wall Liebert air conditioner, see here, the edge was weak and mostly with in 4 inches of the wall.
    In another life Stan Paddock has access to a band saw, so he did some fancy measuring and fancy sawing, and Murphy lost the battle (old 1960s joke). Lookin' GREAT :-)) Glenn Lea is placing a cutout and protected tile for the operator side of the 1401. Only the tape cables come out of the other side. Note the holely floor tile, to pass cool airconditioned air into the 1401 fans.

  • And the many cables get really cruddy over the years. Frank King is motivated to have clean cables so that further handling and laying is not so distressing.
    Frank and Stan with 'em all stretched out. The cardboard helps absorb the liquified crud. Frank and Glenn working on the cables where they are wired into the 1401. Frank and Glenn still at it - the cables were much more pleasant to handle - see laying cable further down.

  • When Bob Feretich took over the + 60 volt capacitor testing above, I wandered over to the six Connecticut 729 mod 2 tape drives, They are not very pristene!! I played with a side panel that didn't stay on. Glenn and I eventually
    a) applied WD-40 and motion to free up the latch
    b) rebent a bent bottom support
    c) and re-adjusted and unbent the catch
    Then noticed that the loading window was taped to stay up, but would not stay up.
    The protective metal has been removed from the window supports. Both cables broken, at least one spring broken. Details of right side support More details
    Then I went to the next drive in the line, second from north - and the loading window was stuck up. It would hit something hard when lowered about 1/4 inch
    Missing interlock activator clip Load window hardware seems good but there is a problem here.

  • The cables are clean, Frank is happy and left, Ron gives Stan and Ed technical information of which cable end go to which machine from the 1401.
    My those are long cables, nice that they are clean. Cables toward the 1403 printer - we did not connect any end points such as the 1402 and 1406. End of a long day, lookin good :-))

  • But in the meantime, something has gone wrong with the German tape drive. Seems like an old logic problem - read goes forever - past all interrecord gaps. And we can't find a working version of Dan McInnis's BIGPRINT-Tape, or there is a problem with the German 1401 :-((


Sat May 10 - class visit

"Our" software group leader, (Dr.) Ron Mak, originator of ROPE, author of 20 Lessons Learned from NASAs Mars Exploration Rover Mission, brought his Santa Clara University class to CHM, and our 1401 restoration :-))
With Bill Worthington
in Visible Storage
With Dave Cortesi
in 1401 Restoration


Wed May 14 - general

  • Present were: Present were Ron Williams, Frank King, Bill Flora, Bob Feretich, Joe Preston, Stan Paddock and Ed Thelen.

  • I (Ed Thelen) came to work, happily humming, planning to do the Connecticut 1402 20 volt power supply, and maybe start the six or so power supplies in the CT 1401. Frank King pointed out parts are missing for the Card Tray support system.
    - All that changed as I was told that the reader motor in the German (DE) 1402 had over heated last Saturday and strange things were happening - I love motors also -

  • The over-heating of the DE 1402 Card Reader motor was puzzling. Ron Williams suggested that one phase of the 3 phase motor was left on when the motor was turned off (the heavy duty relay opened). He reported that the motor seemed to stop much more slowly than normal. Maybe one contact of the relay was stuck shut. Well - all contacts opened, the contacts looked reasonable, but the motor was still getting hotter and hotter !! Time to turn off the system power.

    What a puzzle - Stan came by so I watched motor voltages and heating (back side of 1402) and he worked on the relay, fuses, and other circuity (front side).

    After a while, Stan found that one of the snubber circuits (with series 47 ohm resistor and 0.5 microfarad 400 volt capacitor was leaking oil - and had an end-to-end DC resistance of 12 ohms instead of the expected many megohm resistance :-| Not visible is the slight swelling of the metal case - In the background is a proper snubber, from the 1402 in visible storage. That machine now has one snubber left of six, so maybe other people were having snubber troubles also

    The snubber circuit is across (in parallel with) the relay contacts, to reduce the inductive kick and sparking when the circuit opens. This reduces relay contact pitting and reduces electrical noise. What a surprise, none of us had ever seen a shorted oil filled capacitor before. We had trouble believing this could be the problem, assumed it must be something else :-((

  • Ron Williams, Bob Feretich, Ed Thelen looked for/found power supply schematics in Allison's area, and made an inventory of what is in "box 22" or was it "area 22" ;-))

  • Ron Williams and Bob Feretich checked that the all fans rotated - yes - but the rundown time is quite short, Probably a good plan to disassemble and lubricate them all -

  • Frank King began checking his new 1403 printer -

  • Alan Taber came by. Alan of IBM arranged the long distance hauling of our Connecticut 1401 system. We were delighted to let him know that the move seemed perfect :-)))
    We then took him on a special tour of the Babbage Difference Engine #2 newly arrived from London.


Wed May 21 - General

  • Report from Ron Williams - Present Ron Williams, Tim Coslet, Judith (time sharing with front desk duty).

  • Ron Williams ran some tape programs, found failing loop in a previously working demo program, waiting for author to try to help diagnose the problem.

  • Tim was going to repair a computer card - not sure if he did.

  • Kind of a nothing day


Wed May 28 - general

Planned "All Hands Meeting" postponed until late June -

  • Present were: Present were Ron Williams, Frank King, Allen Palmer, Bob Feretich, Joe Preston, Stan Paddock, Robert Garner and Ed Thelen.

  • This was a fun day :-)) Including some visitors - Len Shustek (chairman of the board) dropped by to say hello -
    Allison Akbay and William Harnack (left) of the Registrar's function came by to measure and record some of the units and serial numbers - Billie Dungan and Reginald W. Oldershaw came by. Reggie had worked at Ampex (about 5 miles away) starting about 1967. I had fought with Ampex tape drives about 1961 - and we had some laughs together. (He seems to have some patents.)

  • The nagging trouble that BIGPRINT based demo decks would no longer work is solved. This problen started weeks ago when the DE 1401 was moved a little to make room for the CT 1401. Simple tests and demos still worked but BIGPRINT would read all the cards and hang waiting for more cards.
    Ron and Ed are discussing the symptoms -
    It was a mighty struggle between two stubborn men and one stubborn beast !!
    And you thought mules have a reputation !!!
    Stepping through the code, Ron & Ed *finally* realized that subroutine returns were returning to the start of the subroutine rather than to the calling code :-(( Subroutines are used to read cards and many other functions -
    The first instruction in a subroutine must be an "SRB" which saves the B register (address of instruction following the "CALL") in the branch instruction at the end of the subroutine. But the address of the start of the subroutine was in the B register, causing the unintended infinite loop.
    This is the guilty card !! Identified by Ron Williams and Robert Feretich :-))

  • Frank King (our printer guy :-))) installed tough new Kapton plastic ribbon between the printer hammer magnets and the armatures. If there is no gap - caused by the 2 thousands inch thick plastic ribbon, the armatures do not release quickly and other side effects -
    This involves punching securing holes in the Kapton ribbon exactly correctly so there is no slack, threading the thin ribbon through the thin magnetic gaps of 34 hammers/section, hot gluing the ribbon ends over the hooks to assure permanence, and takes patience and fortitude -
    The job ain't done until the paper work's complete ;-))

  • Stan Paddock, our jack of all trades, and floor layer, worked to replace some slightly thicher raised floor "tiles" with "new" thinner ones. The different thickness although less than 1/4 inch, is disconcerting, and a tripping hazzard to those of us who shuffle along rather than high step ;-))

  • Joe Preston, who has been patiently struggling with one of the 026 key punch print mechanism for seemingly months, finally reassembled it
    - only to realize that during re-assembly, one of the multiple "cams" in this assembly had shifted during re-assembly, and he had to disassemble it all over again. Bob Erickson, our "famous" mechanical "genius" says that only one or two people in a region were really qualified to reassemble the 026 printers.

  • Ed Thelen, after steping through subroutine code (above), finally got to check one of his beloved linear power supplies.
    Why Ed enjoys square iron transformers and round electrolytic capacitors is unknown - maybe only Freud can guess?? Robert Feretich kept Ed from electrocuting himself - mostly Bob's legible hand writing in the log book :-))



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