Schedule April-June 2005

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go to Schedule 2005 July - September

April 2, April 6, April 9
April 13, April 16,
April 20, April 23,
April 27,
May 4, May11, May 14
May 16, May 18

• Saturday April 2nd - 9:00 A.M. - Special Session -
  Present were Robert Garner, Ron Williams, Bill Flora , Ed Thelen. The newly connected 18 KVA Pacific Power was carefully examined for input transformer taps. (The taps used by IBM were satisfactory for our power also.) The output power tap selection was calculated and set. Ron Williams removed various jumpers and a switch used to cheat to get the system to come up with the 5 KVA Elgar unit. The Pacific Power was gingerly brought up following instructions in the manual.
  At first there was no voltage on the test points although the front panel display lights were correct - then Bill Flora figured that IBM might have set the analog voltage control to zero and cranked up the master voltage screw adjust - walla - voltage :-)
  Pressing the "OUTPUT ON" brought voltage to the 1402 :-)) Adjusting the master voltage screw brought the 3 phase output voltages to 220, with a little fine tweaking on the two fine phase adjustments.
  The added circuit breaker in the 1402 was set "ON" and there was utility power in the 1401. The System ON switch on the 1402 was depressed, and the 1401 main power came on without 5 seconds of relay chattering and excitement. Just click and 1401 main power was ON :-)))
  There was some excitement about voltages after power was applied to the 1401, but that turned out to be a measurement error, not a power error.
  Bill Flora decided to try to fire up the 1402 card reader motor while the 1401 power was on - and it worked !! :-)) (With the 5 KVA Elgar, you could not have the 1401 on and the card reader motor on at the same time with out tripping the protective circuitry in the Elgar :-((
  And we accidentally even had the phases in the correct sequence, the motor was turning in the correct direction.
  The 1401 takes about 1/3 of the rated capacity of the Pacific Power !! We think we have lots to spare - even some extra to start motors with !!
  That took us to about 3:00 - Ron and Bill stayed to bug shoot the 1401 -

  We seem to have victory over the power situation that has been plaguing us for the past 6 months.
  

  	April 6th - Isn't this a lovely picture. With the new 50 Hz power supply, Frank King can start and run the main motor of the 1403 printer, and all the other motors also. That spinning inside-out motor near Frank's right hand is the chain drive motor. The fan at the lower right was apparently running backward for years. :-| In the background, the 1401 is also on :-))
  	April 6th - Don Cull working a stubborn card sense problem. The meters are into the timing circuits. And note Milt Thomas and Ron Williams in the 1406 extended memory. Before today, this memory had to be disconnected to get the 1401 up or the Elgar would trip OFF. Life is good.
  	April 6th - Founder of the Feast !! This Pacific Power 390G 50 Hz supply has more than three times the power of the previous Elgar. The 1401, 1402, 1403 and 1406 running concurrently uses about half of its capability :-)) Previously only one unit at a time could be usefully on, and we couldn't even start the 1403 printer motor. Ed Thelen is glowing, and the 50 Hz converter is cool ;-))

• Wednesday April 6th - 10 AM - Roll up sleeves -
  We *have* victory over the power situation that has been plaguing us for the past 6 months. The new Pacific Power unit has sufficient power.
  Present were Ron Williams, Frank King, Don Cull, Milt Thomas, Robert Garner and Ed Thelen. Life was *GOOD*.
  Instead of negotiating who can have power when, the following were all happening simultaneously
  • Don and Milt were running the 1402 card reader motor - working a card sense problem.
  • Frank King had the 1403 hydraulic paper feed motor running for the first time. (The previous 50 Hz power unit couldn't even start it.) The chain drive system, ribbon alignment and reversal works fine. Paper advances and slews. :-))
  • Ron Williams connected the 1406 memory extension (disconnected because of insufficient power) and verified that the first 12,000 characters of memory can be written and read correctly. (Also a lot of registers and gates have to work correctly to do this!) (1401 memory did not work at all with the 1406 removed.) :-)))
  Robert Garner verified that with all the above going on, the Pacific Power unit was loafing along at less than half rated capacity :-)))

  A thank you message from Robert Garner

  Joy of joys, we now seem to have solid 50-Hz power! Murphy was asleep this week as everything went smoothly with the bring-up of the Pacific Power 18-kVA power converter (recently acquired from an IBM San Jose surplus property bid). Today we continued our run from Saturday by powering the 1401 CPU, its 1406 (12K core), the 1402 read motor, and the 1403 motors, all at once - no problems! The Pacific Power unit is a real pleasure! (Allen wasn't able to make it in today, so his 729 was blue with envy... ;-)) The 1402's master AC power relay clicks on briskly now and its 50-Hz ferro-resonant transformers sound happy. ;-) I'd like to take this opportunity to thank everyone who made the Pacific Power acquisition possible and their exalted help: (sorry if this is a repeat msg - I've had trouble mailing this msg out...) Dave, Gary - Thanks for recommending the unit to us, shepherding it during its last months at IBM San Jose, making the Museum aware that we could bid on it, and providing documentation, technical support, & Pacific Power contact information. You guys were right - it's a great product! Mitchel (@Pacific Power) - Thanks for answering our questions, we really appreciate the support! Your unit is still pulling fine after 30 years! Mike F - Thanks for the care and feeding of the IBM bid process! Mike Z (@Exhibit Oasis) - Thanks for moving and installing the unit! Jim Yee [via wireless connection] - Thanks for the severals days of installing the new AC power wiring and circuit breakers! Sorry if we sidetracked you a bit. ;-) Ed, Allen, Ron [via wireless], Bob, Frank, et al - Thanks for your patience and critical evaluations as we searched for a replacement to the Elgar! (Motor-generator-set cameos notwithstanding! ;-) Grant - Thanks for supporting our decision to bid on the static converter. - Robert p.s. We acquired 36 kVA worth of static power conversion in two racks, but have hooked up only one of the racks, for 18 kVA. I expect this will be sufficient for the whole 13 kVA system we have. (Although Mitchel at Pacific Power notes it's margins may allow it to supply 22 kVA.) Today we were drawing a max of: 2.8 kVA on PhA (46%), 2.4 kVA on PhB (40%), and .55 kVA on PhC (9%) for a total of 5.7 kVA. (The 1401 specs list this configuration at 4.9 kVA.). No 729 in the mix yet. (Last month I measured Allen's 729 at 860 VA, which is less than their rated 1.6 kVA.) We were able to use the simple 301F control unit and didn't need to reconnect up the cut/long cables for the advanced 301E programmable control. Only repair was replacement of the green ON pushbutton bulb. (For the record: for an irritating hour on Saturday, we had a grounding problem with my scope that misled us to believe we had wildly unbalanced phase voltages.)

• Saturday April 9th - 10 AM - Roll up sleeves - (free food ... )
  We now have lots of power :-))
  • Present were Ron Williams, Robert Garner, Tim Coslet, Bill Worthington, Bill Selmeier, Rafael Skodlar, Ed Thelen - and Brian Knittle with his Documation card reader.
  • Ron Williams found 2 more bad cards in the 1401 while starting to check instruction (program) counter logic.
  • Bill Selmeier used his laptop and Brian's card reader and control program to read many 1401 oriented IBM card decks. Bill Worthington fanned, joggled and manipulated the cards and Ed Thelen recorded. See report. Bill Selmeier's report did not mention that we input "Edith" - a moderately "naughty" (for 1960 IBM) printer program.
  • Ed noticed that neon lights glowed in 4 of the 9 Pacific Power power amplifiers. A glowing neon indicates one or more of the 20 or so fuses in each glowing power amplifier has blown. Robert, Rafael, and Ed swapped out the glowing units with power amplifiers from the slave unit in storage. Hot swapping does indeed work ;-)) Paula of the staff blessed the swap.
  • Tim found an apparently shorted punch bail interposer contact in a key punch.
  • Ron Mak dropped by and left 2 boxes of "1403 printer music" decks :-))

• Wednesday April 13th - 10 AM - Roll up sleeves -
  April 13 - A truly beautiful day, lotsa power, lotsa folks, lotsa progress, lotsa fun :-))

  Allen & Grant

  Busy Busy

  Allen & Frank Loading 729

  Chuck & Don

  Allen Running 729

  
  As Jackie Gleason used to say "How sweet it is!!"
  • Lotsa power, lotsa folks, lotsa work :-)) In attendance were Ron Williams, Bob Erickson, Don Cull, Chuck Kantmann, Robert Garner, Grant Saviers, Ed Thelen, Milt Thomas, Ron Mak, Bill Selmeier, Allen Palmer, Bill Worthington, Frank King and ??
  • Grant was in his knee brace and a bit slowed down. Restoration may be safer than skiing ;-))
  • Bill Selmeier, Ron Mak and Bill Worthington read cards using Brian Knittle's card reader. See report.
  • Allen Palmer got more functionality out of the 729 mod 5 tape unit. Robert Garner will bring some "Load Points" next time. Apparently analog recording tapes use the same little reflective strips to signal "start of data area" and "you are almost at the end of this reel" as the digital world? Robert Garner measured the tape unit as using about 1.3 KVA :-))
  • Ron and Bob struggled with the 1401 processor. The smiles of last Saturday turned to frowns today as manual memory tests that worked well were intermittent today :-((
  • Frank King placed some more skins on the 1403 printer - can't find a back panel that has a slot for a paper stacker control. :-? Frank reminds us that we should get several to 10 boxes of the wide pinfeed paper into the restoration room for coming printer tests and alignment :-)

  • Don Cull, Frank King, Chuck Kantmann worked on 1402 reader timing. It was determined that the card reader timing circuit breakers were worn to the point of unadjustability - and requested permission (via the approved form) to swap with the unit in Visible Storage Dag Spicer wants to think about the above request for a few days - highly concerned about restoration "reversibility". I suggested that maybe he could give us a half hour reminder on "reversibility". (We tend to be task oriented of "getting the machine to work" :-))

  • In the Pacific Power 390G - we are in the process of blocking the recirculation path of some of the warmed air back to the cool air input side - the inlet air temperature to the top power amplifier is noticeably warmer than to the others. The phase currents to the 1401 are very unbalanced. Exhaust air from phase A and B power amplifiers is noticeably warmer than the C phase power amplifiers.

• Saturday April 16th - 10 AM - Special Session - Reading cards
  See report.

• Wednesday April 20th - 10 AM - Roll up sleeves - We had Ron Williams, Bob Erickson, Don Cull, Robert Garner, Allen Palmer and Ed Thelen.
  We received a surprise visit from Gene Amdahl, designer of WISC, project engineer of IBM 701, an architect of the IBM 360 series, and founder of Amdahl Computer Company with Amdahl V-470 :-)).

  Gene Amdahl with ALDs

  Gene w Don Bob Allen Ron

  Gene with Allen Ron Bob Don

  It turns out that:
  • Bob Erickson worked for Gene for a few weeks on the IBM 701 project. Bob had finished 701 CE school class #6 but the Los Alamos computer was not yet ready. While waiting the few weeks for Los Alamos, Bob was assigned by Gene to see if Bob could fit an index register into a specified volume of the 701 main frame. [Bob says the 701 was behind a wall of glass - to get to the computer you had to leave that area to get to the proper door to get near the computer.] Gene reminded us that the 704 was the first computer with true index registers - the British "B Box" was simply a counter indexable by only one.
  • Harlan Snyder (a docent at CHM) worked for Gene in Palo Alto at IBM's Advanced Research something. In a previous life, Harlan had worked with the ERA ATLAS computer.
  Regular stuff
  • Dag said we should order printer paper ourselves - say from Inmac or Office Depot
  • Dag gave permission to swap the CBs (see picture above). But by the time Chris & company got done discussing wire tagging ... it was 2:30 and the tours were on.
  • Robert brought in 3 LED voltage displays to show 3 phase voltage outputs of the Pacific Power. Ron is cutting 3 square holes for mounting and Ed will supply a flexible input 5 volt output power supply.
  • We asked Dag for say 5 boxes of IBM cards. He said that there is a whole pallet in our warehouse in NASA. A few weeks?
• Saturday April 23rd - 10 AM - Roll up sleeves - (4th Saturday)
  We had Ron Williams, Tim Coslet and Ed Thelen. I guess cup cakes just don't attract - Betsy Toole must bring brownies!! ;-)) Interesting day.
  • Ron had cut square holes for three LED voltmeters in the panel that Robert bought.
  • Tim used his in-circuit tester to examine printed circuit boards that Ron had identified as bad. There were so many bad components that one wonders what is going on. On one board, all seven input diodes were open, another board had two bad transistors and a resistor that was 16 ohms instead of 43 ohms. On several boards, the 56 microhenry peaking coils were open.
  • Ron found 4 more bad boards.
  • Ed went to a boy's toy store (Halted) and got 30 1N87A germanium diodes for Tim, and a 110/240 volt to 5 volt power supply for the panel meters (above). We looked up in Jameco and Digitek for additional parts like sockets and terminal strips.

  3 new voltmeters :-))

  Tim, bad circuit

  Tim, good circuit

  Tim - Pensive, what is this thing trying to tell me?

  Ron at the console

• Wednesday April 27th - 10 AM - Roll up sleeves -
  Ron Williams, Allen Palmer, Don Cull and Ed Thelen were present.
  • Ron found more bad boards in the 1401.
  • Don Cull installed some CBs ( cam operated circuit breakers) from Visible Storage and, with help from Allen, worked to assure correct timing
  • Ed removed bad components (as determined by Tim and his in-circuit tester), and installed replacement components from 4 printed circuit cards. One card had 4 bad transistors, another had 6 bad diodes. There is some question if/why such massive failures.
  • Allen took apart a 729 "PROLAY". This is the magnetic unit that operates the 729's pinch roller to move or stop tape. He is currently looking for a source of AeroShell 14 lubricant - as specified in the manual.
  • A preliminary study of the Prolay pinch roller mechanism

• Wednesday May 4th - 10 AM - Roll up sleeves -
  Ron Williams, Allen Palmer, Bob Erickson and Ed Thelen were present.
  Bill Flora brought in a 1403 manual he printed off of Paul Pierce's web site:-)) then had to go back to (paying) work :-((
  • Ron and Don found more bad boards in the 1401. Still having problems accessing memory from the front panel - did better last month.
  • We have 3 boxes of blank cards to play with. - Dag Spicer says we have a million more in the warehouse :-))
  • We have a box of printer paper to play with :-)) Can get delivery in one day from Office Depot.
  • Allen took apart a second 729 "PROLAY". He ordered 14 oz of AeroShell #14 from McMaster Carr for 10ish dollars including shipping and tax. He feels that the mechanicals for the second 729 Mod V tape drive will be ready "Real Soon Now". :-))
  • Ed removed bad components (as determined previously by Tim and his in-circuit tester), and installed replacement components from 3 printed circuit cards.

• Wednesday May 11th - 10 AM - Roll up sleeves -
  Lets see - Ron Williams, Allen Palmer, Bob Erickson, Frank King, Don Cull worked on the the 1401 and 1406 memory access, 1402 reader punch, and 729 tape units. Robert Garner (back from Yorktown Heights) checked in and delivered the baggles for lunch.

  Grant Saviers delivered 4 tiny screws he made for Allen's 729 tape units that a machine shop said would have cost - was it $50 each? Great to have a resident machinist. Yes that is a penny in the background - notice the odd shaped heads, extended shoulders, and sharply butted threads. Now if we could have a drill press in the museum?

  The 077 collator that Bob Erickson is restoring had a makeshift electronic power supply instead of the original 48 volt motorgenerator. I forgot to form the capacitor in that makeshift power supply - and it got hot, ozzed and charred. A trip a "boy's toy store", HSC Electronic Supply, or Surplus Solutions, will provide a replacement.

  
  Bill Selmeier, Randy Neff and Ed Thelen stripped hardened rubber bands off of IBM cards - some of the rubber bands glued 2 decks together, and some flowed through holes - sticking more cards together and creating a new kind of hanging chad - , collected all the "meta-data" possible (what the heck is this deck? any clues?), read and verified 3 boxes of cards (78 decks) onto CD ROM. Some of the "decks" were 1 card. I know that doesn't sound like much - but after 5 hours we were really tired. We have 9 more boxes in this batch.

  Yes, this is Randy Neff with pen knife trying to get a card ready to read. (We did not save the decomposed red rubber band :-(( ;-))

• Saturday May 14th - 10 AM - Roll up sleeves -
  Ron Williams, Tim Coslett and Ed Thelen attended.

  Ron continued to trouble shoot the 1401. A widely distributed clock pulse has a good rise time but a very slow fall time. Tim tested the source board - seemed OK. Tried several replacement cards. Chased the load paths - nothing dramatic, found an obvious error in the ALDs - there is no zero board. Decided to live with it for a while

  Alex, what is this?

  
  Tim Coslett continued to trouble shoot boards with his in-circuit tester. He replaced components in a number of boards. Must remember to get some more 56 microhenry inductors - would you believe more than two were open?
  Ed brought in six 026/029 keypunch printer ribbons. After installation in the 026, we found maybe half of the print matrix wires are not printing. Is this a lubrication problem? Bob Erickson - HELP. Replaced the sick capacitor in the juryrigged power supply for the 077 collator - then found the output current limiting circuitbreaker bypassed - Tim helped restore to what appears to be originally intended wiring. Power supply rated at 2 amps - does the 077 take more and that is why the breaker was bypassed?? The input fuse holder was found broken and also bypassed. We should install a good one. Wild!!

• Monday May 16th - Card reading special - from Bill Selmeier -
  More progress on the 1401 Cards was made today. Randy Neff and I spent 5 hours and read an awesome 5 of the remaining 9 boxes of cards. As we've said before, we see the light at the end of the tunnel. The cards are being read in Binary using Brian Knittel's agile card reader. The card stock today was in better shape than we encountered in our earlier work on the cards that came with the IBM 1401. Except for problems with rubber bands that had deteriorated over the years. These cards appear to have originated in the 1975 time period. While the major portion applies to 1401 Emulators on S/360 and Burroughs computers, there are also program that appear to be doing financial activities. Al, 4 more boxes to go and you can have them to return. Randy and I have tentatively set aside this Friday to continue and hopefully finish the task.

• Wednesday May 18th - 10 AM - Roll up sleeves -
  Present were Ron Williams, Bob Erickson, Tim Coslett, Don Cull, Chuck Kantmann, Milt Thomas, Frank King, Robert Garner, Ed Thelen
  - I bought a can of WD-40 and Bob went after the faulty print head of the 026 keypunch. He found an opening to the print wire matrix and in went the WD-40. After 2 round of "lubrication" and testing, most of the printed characters were mostly recognizable, but badly flawed by missing dots.
  - Time for heroism - Bob had previously stated that he didn't want to work on the print mechanism - but desperate measures were needed. Bob said that he had taken one apart many years ago - but didn't get it back together - Bob and Milt removed the print head mechanism.
  

  taken to help re-assembly :-|

  that funny "nose" is the wire guide casting

  "Wire Plate" - several raised spots are missing - photo from Robert

  OK - now what?

  About Printing - added Mar 21, 2014

  The question came up on how did IBM manufacture the print head for the IN\BM 026. The attached picture gives a big clue. All but one side is an aluminum casting The wires are fed down from the top to holes at the bottom. Then a low melting point metal was pored into the casting. Evedently, the wires did not bind to the metal. Clever people at IBM. Sombody at the 6800 group meeting suggested this last week. Whoever that was, feel good that you were right. The picture is 400 pixels per inch so you can magnify further to see more datails. Stan

  The code plate that causes the printing wires to press the ribbon and punched card are discussed on pages 4-25 & 4-27 of 029 Field Engineering Maintenance Manual (4 megabytes).

  The print head is identical to that in 029 Field Engineering Maintenance Manual (4 megabytes)
  - The printing mechanism is now back together, but the instruction book says "insert aligning tools", but we don't even know what they are talking about, so we are trying to print an "H" by moving the "wire plate" in x and y. Hope to complete next session. Every adjustment seems too large. :-||
  - Ron and Frank worked on the 1401.
  - Don and Chuck replaced six of the timing breakers on the read side of the 1402, and re-timed them.
  - Tim brought in his scope and in-circuit tester and went after some of the defective SMS cards.
  Post Script: from John Van Gardner

  I am attaching a photo of page 66 from my IBM General CE Tools Reference Summary form number S131-0075-3. It has a picture of the alignment tool and part number. It was nothing more than small rod with a bent end to use as a handle. The hole in the code plate is the size of a number 41 drill bit. Any rod this size could be used. It was used as the starting point for mechanical adjustment of the print unit. If it was not used you could run out of movement in one direction when printing.

  
  Post Post Script: from Allen Palmer 5/22/2005
  

  There is an alignment tool in my toolbox on the desk. Look in one of the plastic boxes. I showed it to the guys about 2 weeks ago. It looks just like to picture John sent you. You insert it through the hole in the casing frame, through the print plate and align the plate & secure the plate. Just remember to remove the tool before you try printing.

• Wednesday May 25th - 10 AM - "All Hands Meeting" - Boole Conf Rm. - Robert is writing a report.
  - 11:30 AM - Roll up sleeves -
  Present were Ron Williams, Glen Lea, Frank King, Robert Garner, Ed Thelen. We showed people around then Ron trouble shot the 1401, "assisted?" by Ed.
  Harlan Snyder is bringing his microscope this Saturday to look for failure modes of the point contact diodes that are failing. Robert took one of the failed 56 uHenry coils to his work place to try to analyze why a coil of wire can fail.
  We asked permission to swap some type AHD SMS cards with the Visible Storage 1401 and were turned down. We have to wait for Tim to repair some more AHD's.
• Saturday May 28th - 10 AM - Roll up sleeves - (4th Saturday :-))
  Present were Ron Williams, Tim Coslett, LaFarr Stuart, Harlan Snyder, Ed Thelen. Ron continued to trouble shoot the 1401. Tim repaired defective cards. Harlan brought his microscope to view failed diodes- but the noise, vibration, desk height, were not helpful. He took some failed diodes home for visual analysis in a better environment.
• Wednesday June 1st - 10 AM - Roll up sleeves -
  Present were Ron Williams, Frank King, Allen Palmer, Ed Thelen, Robert Garner. Allen is back from Florida - we believe he went there to avoid the May 25th "All Hands" meeting ;-)) The group talked some about the future of the 1401 - especially "living presentation" and continuing maintenance.

  
  - - - - - - - start printer fuse - - - - - - - - - - - - - - - -
  Frank is having trouble with a fuse blowing when powering up the 1403 when connected to the printer buffer controller.
  We don't have prints of the printer buffer controller so Frank wanted to compare a resistance value between 2 pins in the Restoration 1401 with the Visible Storage 1401.
  The -60V, 3/4 A Fuses that supply the 1403's core-memory line buffer, physically located in the 1401 CPU, have been consistently blowing. Frank had measured 10 ohms between the two core-memory -60V supply lines and ground, clearly far too low. He measured 10 ohms and 60 ohms on the 1401 in visible storage.
  On Robert's suggestion, he disconnected all other supply wires connected to the 1401 logic gate (card cage). This resulted in about an acceptable 1k ohm of resistance when the +6V supply line was disconnected. Implication is a short to a +6V-powered component?

  
  - - - - - - - start Misc. - - - - - - - - - - - - - - - -
  Allen used Krazy Glue to adhere some delaminated tape drive PROLAY MuMetal shielding.
  Harley Snyder reported that the several open diodes he examined under his microscope likely have corrosion problems, he did not see the expected broken point contacts. (There have been some, and this is a known failure mode of point contact germanium diodes. Robert is examining them, and may send them to a failure analysis lab.)
  Ron found another bad card in the 1401- a diode on the card had part of it's glass envelope broken off.
  

  Ed and Robert vacuumed the dust and crud from the SMS cards in one logic gate (card cage). Crud was thickest inline with the fan. We resolved to clean one gate per session.

• Wednesday June 8th - 10 AM - Roll up sleeves -
  I was vacation until June 14th :-))
• Saturday June 11th - 10 AM - Roll up sleeves - (2nd Saturday - Free food)
  Tim debugging SMS cards
• Wednesday June 15th - 10 AM - Roll up sleeves -
  Present - Ron Williams, Don Cull, Frank King, Allen Palmer, Ed Thelen.

  	Don and Frank working on the 1402 card reader/punch timing the 15 or so reader "Circuit Breakers" (mechanical contact points of the same idea as old fashion car ignition points).
  	Frank explained that there were two organizations of read brushes, the 2 group (2 different brush lengths in a brush group, and the 3 group (3 different lengths). Brushes are from Ron's private stock, nickel in mine, courtesy and permission to photograph from the U.S. government. Ron and I grant you permission to use this I.P. "Intelictul Proprty" ;-))
  	Ron was on his knees most of the time - I'm not sure which good luck charm he is begging favors from this time - maybe VOODOO this/next time? Ron made the low chairs and kneeling pads we use, but he doesn't use them - saying that his knees are already shot. Today, Ron was able to insert and execute a two instruction program - NOP, BRANCH back to to the NOP instruction. He showed me how to operate the console and step through the program - then gave me a certificate of completion. :-))
  	Allen and Ed worked on a 729 Mod 5 tape drive. Allen has an eye patch for an inflamed iris, and Ed has sore knees - but we had enough human working parts to continue. ;-))
  	Our 729 alignment procedures are for the Mod 4, and mentioned changing a 50 watt potentiometer until 4 volts is measured on TB11 across terminals 8 and 9 - two big 2 ohm resistors in parallel. The Mod 5 TB-11 has only 8 terminals. The schematics seem to be for a different revision Mod 5. We tried to chase wiring for three house, but trying to remove some of the chassis without disturbing other chassis too much got tiresome. We measured all combinations of voltages on the 8 terminals of TB-11 and did not find any within 25% of 4 volts- so we started physical adjustment of the rebuilt PROLAYs. Like what would you do? Maybe it will work anyway.
  	Ron William's log of failed components so far (44 subtotal).

• Wednesday June 22th - 10 AM - Roll up sleeves -
  Present - Ron Williams, Don Cull, Dave Cortese, Robert Garner, Ed Thelen. Two new prospects, Ron Crane and Bob Feretich, showed great interest - :-))
  • Dave and Ed checked out the indicator lamps in the printer alarm panel to the lower right of the ribbon assembly. 3 of the 8 were bad and another had a lose wire. Spares were found on the back of the 1401 operator's console, Dave is researching another source.
  • Don Cull finished timing the rest of the ten Read Latch Circuit Breakers. Ed could not believe that the timing adjustments could be set within the specified +-1 degree - but that was accomplished.
  • Ron did not have a good day debugging the 1401. On instructions with data operands (like Add a to b) the machine gets confused about the next instruction :-((
  • Robert brought bagels, good cheer, and rumors of a possible Tektronix 575 curve tracer (for testing semiconductors) :-))
  • Ron Crane and Bob Feretich are both, independently interested in providing a pseudo magnetic tape controller (actually a networked PC talking to the magnetic tape I/O through the termination plug.) This can provide an easier method of program development. (Edit, assemble, emulate, early debug on your PC - test on the 1401 without keypunching :-)) Bob received some schematics and bus timing diagrams. Ron and Ed talked until 8 oclock :-))
• Thursday June 23th - Robert Garner's PowerPoint to the Museum Board
• Saturday June 25th - 10 AM - Roll up sleeves - (4th Saturday)
  Present - Ron Williams and Tim Coslett. Ron circuit and signal traced trying to get the machine to recognize/process the instruction after a two operand instruction completes. Ron and Tom worked on previously detected bad cards replacing transistors and diodes.
• Wednesday June 29th - 10 AM - Roll up sleeves -
  Present - Ron Williams, Don Cull, Allen Palmer, Ron Crane, Robert Feretich, Ed Thelen.
  • Ron W. had a good day with the 1401, The machine can now process (not necessarily correctly) multi-operand instructions with out getting lost. Conditional branch instructions work.
  • Allen and Don worked on a Mod 5 tape drive, then Allen and Robert F. worked on tape channel logic and timing.

  • Ed Xeroxed two tape oriented ALDs then helped Ron C. verify that Allen Palmer's old IBM scope has a CRT filiment transformer winding shorted to ground - shorting -3000 volts. Here is Ron Crane with a robust 10 megohm resistor that he just bought (with a 1 megohm voltage divider) preparing to measure -3000 volts. :-))

  go to Schedule 2005 July - September