IBM 1401 Team at CHM

A wonderful day down at the farm

2012-01-14T22:01:00.000-08:00

Several weeks ago, Jim Somers from the CHM dropped in with a special request.

There was a young man (David) and his girl friend (Julie) who would like to visit the museum. The problem is he is blind.
Since the 1401 restoration room is the only place in the museum that has equipment that can be 'touched', Jim asked if he could schedule the vist for Saturday, January 14th which is one of our work days.

We told Jim that was no problem and bring David in.

The Wednesday before that date, we were working on the German 1401. It had several card failures.
Late in the day, the Connecticut machine decided to fail.

On Friday, I convinced Jim Hunt to join me at the CHM to try and get one of the machines up and running for Saturday.

Jim Hunt fixing another IBM 1401 SMS cards.

Stan Paddock getting his finger stuck in some piece of equipment.

After spending the day working on the German machine, we were not able to make it work. We thought we were close to the answer when we started but were not successful

On Saturday, Ron Williams, Bob Edwards, Jim Hunt, Gary Feierbach, and myself came in early to attack the problem.

Ron Williams working on the Connecticut machine's problem.

Bob Erickson working on a different problem.

Ron, Bob and myself worked on the Connecticut machine while Gary and Jim worked on the German machine.

Jim McClure, from the museum staff, was escorting David and Julie through the rest of the museum. At noon, I went to find them and let them know we were still down and maybe they should wait until after they had lunch to come in to the 1401 room. They said OK.

When I returned to the 1401 room, Ron informed me that the Connecticut machine was back in operation.

I went back out on the floor and invited Dave and Julie into our room.

Understanding David's limitations, we gave him a modified tour where he was allowed to touch the machines involved and even inside of the IBM 1402 where the cards passed through rubber rollers into pockets.

David was given our sample core memory module and he could feel the actual ferric core beads.

We ran the 'Big Print' program for David and Julie and 'Powers of 2'.

David ran his fingers over his name punched onto an IBM punched card and was told how to decode the punched holes. He thought that was cool.

While he could not read the printout of 'Powers of 2', he was impressed by the noise of the IBM 1403 printer.

I hope David and Julie enjoyed the tour as much as we did presenting it to them.

Stan Paddock

A special Visitor

2012-01-08T19:36:00.000-08:00

On December 28, 2011, The Husman family came all the way from Northridge CA to visit the Computer History Museum at the request of their 10 year old son Glen.

This picture shows Glen, his younger brother and his father. His mother is busy taking pictures.

Glen was very interested in the IBM 1401 equipment. He showed me the programming he had done on his cell phone!

I had some work to do at the CHM and invited Glen to com back on Friday and I would teach him how to program the 1401. He and his mother accepted.

After a whiteboard session upstairs, Glen wrote a "Hello World" program on the IBM PC in the foyer.
He and his mother are shown above.

Glen then ran the program through the IBM 1401 simulator on the IBM PC.
The Glen ran "remote punch" to punch his object deck on one of the IBM 026 keypunches.
After he was shown how to load a program into the IBM 1402 card reader, he did so and the program ran as expected.

Glen was so excited with his success, he decided to write a program that read cards and put the data to the printer with a header for each line. There was an "(EOF)" card at the end he had to detect to stop the program.

This program also worked as designed.
Glen was fascinated that the IBM 1401 system has four "START" buttons so when he demoed his program, he used all of them.

I received the following E-Mail from Glen after he returned home.
I think I may have found a JAVA programmer to fix the problem with our ROPE programming environment!

Dear Stan,
Thank you for teaching me how to program the IBM 1401 (Ancient) Computer. I enjoyed it very much. The Computer History Museum was, by far, the best museum I have ever been to. Thank you for inviting me back to program the IBM 1401. I will definitely like simulating, and programming for, the IBM 1401 at home. I will also like fixing that bug in the simulator, and, maybe adding a new feature, punching directly from the simulator program (so I can click "Punch" on the assembled code screen, and it will punch for me)! Speaking of which, I loved the remote punch feature! Thank you for inviting me.

Sincerely,
Glen H.

Full Restoration of The Connecticut 1401 at the Computer History Muesum

2011-05-26T22:35:00.000-07:00

When the Computer History Museum received the Connecticut 1401 system, the covers for the reader end of the IBM 1402 were missing.

While the machine was fully functional with the missing covers, for safety reasons and aesthetics we decided to find some covers.

We searched the CHM warehouse and all known sources of IBM card reader parts and could not find any of the required parts.

The right hand cover shown above was found in the parts that came with the Connecticut 1401 system.

The lower shelf was fabricated by Stan Paddock with help from Bill Flora, Sam Seibert (San Jose History Museum), Paul Williams (San Jose History Museum) and George Ahearn.

Bill Flora is shown here trying to figure how to get the support brackets into the IBM 1402.

The left hand cover was manufactured by the IBM Almaden research facility with help from Robert Garner. George Ahearn took some of the parts home to his garage machine shop to fine-tune the fit. George Ahearn is shown here adjusting the bolts so everything aligns correctly. Some unique paint was found locally to give the parts the rough finish that IBM used for the rest of the machine.

This is a picture of the card reader end of the Connecticut IBM 1402 with all of the covers in place.

This picture is of the completed Connecticut 1402 with some of the people responsible for the work.

I would like to thank all of the people involved in the fabrication and assembly of the parts to complete the Connecticut 1402.

Stan Paddock

Wednesday May 18, 2011

2011-05-24T21:50:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Bill Flora, Frank King, Glenn Lea, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Jim Hunt, Ron Crane, Judith Haemmerle

Ed Thalen, Frank King and Bill Flora have been working on a problem with the German machine. A very little used instruction "Branch on printer busy" did not work. After tracing the ALDs, they found and replaced the failing card.

I am sure the fact that the German machine cannot load and execute programs has nothing to do with their fix.

Bob Edwards fixed a couple of mechanical problems with the IBM Transmitting Typewriter.

Bill Newman, Doug Martin, George Ahearn, Jim Hunt and Stan Paddock worked on wiring the switches in the typewriter.

Bill Newman and Stan Paddock tested the wiring and made some corrections. The typewriter was connected to Bill's Arduino. All of the typed characters sans two worked!!!

Next week the last of the special switches will be wired and tested and then wiring of the solenoids will begin.

Joe worked on both the second and third tape drives of the German machine. Test will be performed next week.

While it may look like they are working on the typewriter, Bob Edwards, Judith Haemmerle, and Bill Williams are working on a 'Williams' tube prototype.
http://en.wikipedia.org/wiki/Williams_tube

Stan Paddock

Wednesday May 4, 2011

2011-05-04T22:32:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Glenn Lea, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Jim Hunt, Ron Crane, Judith Haemmerle and Don Luke.

Visitors: Five visitors found there way into the IBM 1401 restoration room for an informal visit.

Taking advantage of the warm weather, we enjoyed lunch in front of the Computer History Museum. We had the pleasure of John C Hollar, President & Chief Executive Officer, of the museum join us for lunch. (The only one with a shirt and tie.).

Several months ago, Stan Paddock misplaced his leather hat. This is a common event and most of the time the hat never returns.

Last Week, Dave Wood from the San Jose Fire Museum, found it in an old fire truck I had been driving. Before returning it, Dave felt it necessary to decorate it. Stan had to wear it for a week which included today.

Judith Haemmerle and Bob Erickson continued work on a Williams Tube memory prototype.
http://en.wikipedia.org/wiki/Williams_tube
Bill Newman and Ron Crane are also involved in this project.

Ron Williams and George Ahearn checked out the problem with the feed rollers on the Connecticut IBM 1402. To everyone's amazement, today it works just fine.

Stan Paddock modified his Tape demo program to print while the tapes are spinning. The program performed different on the Connecticut machine from the German machine. The problem is associated with a little used instruction known as "Branch On Printer Busy."

Ed Thelen Don Luke and Glenn Lea are working to find the source of the error on the German Machine.

Joe Preston and Frank King repaired the head lift mechanism on tape drive number two of the Connecticut system. This brings the Connecticut machine back to 100% operational status.

A trip is planned in the next few weeks to retrieve the covers for the IBM 729 tape drives for the German machines. We are also going to try to retrieve some parts for use on our operational tape drives. Pictures and conditions for all our tape drives being stored will be recorded.

Ron Crane is continuing his study to reduce the reactive power being generated by the German system and documenting the true power being used by the Connecticut machine. This information will be required for planning of the up coming modifications to the room.

Jim Hunt, and Doug Martin continued their work wiring the IBM Model B transmitting typewriter. Bill Newman brought in the circuit board that will operate the typewriter when everything is complete.

Stan Paddock

Wednesday April 20, 2011

2011-04-21T00:22:00.000-07:00

Attendees: Ron Williams, Bob Erickson, George Ahearn, Stan Paddock, Frank King, Don Luke, Bill Newman, Joe Preston, Ed Thelen, Jim Hunt

Ron Williams shows off the finer points of an IBM 1403 printer to Ed Thalen. Ed still thinks the printers made by GE were better in that their failure rate kept him gainfully employed.

Joe Preston, Jim Hunt and Frank King discuss the finer points the installation of a cotter pin.

This is the card reader end of the Connecticut system as we received it. While operational, it leaves lots of spaces for fingers to be caught.

This is the same end with the right shoulder installed. The part was inside the machine when we received it. The part was sand blasted and re-painted to mach the two new parts.

The bottom support plate was fabricated by Stan Paddock, Sam Seibert, Paul Williams and George Ahearns.

This picture shows George Ahearns attaching the newly fabricated left shoulder. We are very thankful to IBM Almaden for fabricating this part using the same part borrowed from the German IBM system as a pattern.

Joe Preston read through all of the manuals for the IBM 729 tape drive to find the last problem with the number three tape drive on the German system. When Joe left today, his tape drive was fully functional for the first time since we have received the system.

Stan Paddock

Wednesday April 13, 2011

2011-04-18T22:30:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Bill Flora, Frank King, Glenn Lea, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Allen Palmer, Jim Hunt, Ron Crane, Judith Haemmerle

Visitors: a mother and her daughter. The daughter was in a school play as Grace Hopper.

Stan made a presentation to this Mother and Daughter pair.

Frank King provided hands-on training to the daughter.

The German 1402 had a non-operational “Reader Stop” lamp.

Bill Flora opened the doors, checked the wires, found the problem and fixed it.

The German 1402 did not feed cards right from the big feed stacker.

Bill flora and Ron Williams found that problem and fixed it.

The Connecticut 1402 did not feed cards right form the big feed stacker.

Bill flora Showed George Ahearn where to look and George fixed it.

George Ahearn brought in the card feed tray from home.

Stan further modified it to allow space adjustment.

Stan brought in the new end piece for the Connecticut 1402.

George assembled all of these new parts on the Connecticut 1402.

While everything was close to be perfect, George decided that a little more machine in his home shop would make it perfect.

George took both parts home for final touches.

Jim hunt researched the problem with the X sync pulse not appearing on the control panel of the Connecticut 1401.

After studying the ALD’s, Jim suggested running the system with the punch turned on.

That fixed the problem. Why?, we are not sure. Robert garner and Jim talked about it for some time with no idea coming up.

Allen Palmer came in and fixed a high speed rewind problem on the second IBM 729 tape drive of the German machine.

Allen worked with Joe Preston on the third tape drive of the German machine.

Allan had to go home and Bill Newman worked with Joe on this strange problem.

Then Joe Preston had to go home and Bill Newman told Ron Crane about the problem.

Ron crane found a bad reading on one of the lines that generate the universal reference voltages in the tape drive.

Ron pulled the power supply out of the machine and found a loose lead to the main transformer.

He soldered the lead back and the machine came back to life.

Joe should be happy when he comes back in on next Wednesday.

Ron Crane has figured out the correct values to add to the power lines on the German 1401 system to correct the power factor.

Now he is looking for a place to mount the capacitors. The three caps shown might be a bit small for his needs.

Bob Erickson and Frank were talking about power indicator lights on the IBM 077 collator.

Frank was able to remove the existing light and gave it to Ron Crane.

On went back to his stash of various light bulbs and found a match. We installed the light and tested it. It is strange that the light is on when the machine is on and the machine is not running.

This was a great day for the IBM 1401 Restoration Team. Eight problems were resolved in the same day.

Stan Paddock

Saturday, April 09, 2011

2011-04-11T22:14:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Stan Paddock, Bill Newman, Jim Hunt, , Judith Haemmerle, Bill Worthington, Ron Mak

Visitors:

Samantha Domville, Christopher Douglass , Chio Saeteurn, Christopher Ward, Dinesh Kakumani, Christopher Nelson, Srividya Viveganandan, Jeffrey Ellak, Daniel Li, Andrew Maturi, Tung Bui, Brian LaChance, Denny Tran, Annie Huang, Duc Nguyen, Steven Terpe, Michael Dougherty, Victor Frandsen, Thomas Skrainar, Mason Winner

Ron Mak brought in students from his classes at San Jose State. They were all in awe at how data processing was done in the 1960's.

While Ron was testing tape drives o the German IBM 1401 system, he noticed tape drive number two did not behave right. It made ribbons from the tape and cut it in two.

There is always next week.

=========================================

I have been late the last two weeks and only got those done tonight.

If you want to keep everything up to date, go back to the March 23 blog and go forward.

Stan Paddock

Wednesday April 06, 2011

2011-04-11T21:46:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Glenn Lea, Don Luke, Allen Palmer Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Ron Crane, Judith Haemmerle

Visitors: Bill Kell

Allen Palmer and Joe Preston watch in amazement as the Tape Auxiliary Unit drives the tape drives on the German 1401 system.

Bob Erickson and Judith Haemmerle review the documentation for the connection of the Connecticut 1401 system to the IBM Model B typewriter.

Stan's Father Bill Kell examines the old electronic parts used to maintain the 1401 systems. He used some of the same parts to maintain some IBM equipment for TRW down under.

Ron Crane uses the vacuum to clean out bugs, dust and old electrons from one of the Pacific Power Systems linear amplifiers. Ron replaces the same resistor in two of the linear amplifiers to bring the total system back to life.

George Ahearn and Glenn Lea work on the mounting bracket for the Connecticut IBM 1401 System.
George volunteered to take the part home and machine adjusting slots to facilitate a precise mount.

Stan Paddock

Wednesday March 30, 2011

2011-04-11T21:14:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Bill Flora, Frank King, Glenn Lea, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Allen Palmer, Jim Hunt, Ron Crane, Judith Haemmerle, Bill Worthington, Bob Feretich

A new page has been turned! Ed Thelen is working with Joe Preston on a failed IBM 729 SMS card. Ed said it was close to the cards he knew from the GE tape drives.

Here Ed shows where the IBM 729 tape drives is better than the GE tape drive because it uses two v belts to drive the take up reel.

Here Joe is trying to make sense of what Ed was talking about.

Ron Williams was heard to say "Chassis 1, section B drawer 6, column 3, slot 15, pin J". Now where in the hell is that?

OK, here it is. On the the card with the smoke coming out of it.

Ron Williams and Bob Feretich worked on a persistent card reader problem with the Connecticut IBM 1402 card reader. It was traced down to a faulty SMS card.

This reader has been a source of problems from the day we received the unit. We now feel comfortable that we have found and fixed the last of these problems.

Don Luke helps Frank King (out of sight) re-assemble the underside of tape drive on the Connecticut machine.

Stan Paddock

Saturday, March 26, 2011

2011-04-11T18:12:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Stan Paddock, Jim Hill, Ron Crane, Judith Haemmerle

Visitors: Steve Russel

Somebody has brought in a MAXWELL 8GB thumb drive.

If it is yours, please retrieve it or it will be put to use.

Ron Crane hides behind the Pacific Power Systems machine identifying the power factor on the German IBM 1401 System.

Steve Russel comes into our area to practice with Unit Record Equipment so he can look cool on the museum display floor.

Judith gives up on a difficult problem related to the IBM Model B typewriter. Bob Erickson carries on anyway.

Jim Hunt continues to "hunt" for old parts on-line.

Ron Williams watches the cards go into the Connecticut IBM 1402 card reader. He is looking for the last bug associated reading cards on that system.

Stan Paddock

Saturday, March 25, 2011

2011-04-11T10:20:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Stan Paddock, Jim Hunt, Bill Newman

Jim Hunt researches available devices to replace devices that were used in 1959 when the IBM 1401 was being built.

Ron Crane compares the qualities of one transistor with another.

Ron then built up a capacitor bank to test the phase shift to try to get a an AC power factor of 1.00 from the German IBM 1401.

The waveform for Ron's power test looks good. Or this is the image from Space Invaders.

Bob Edwards continues his work on the IBM model B typewriter.

In the background, Ron Williams continues looking for the read problem on the Connecticut IBM 1401.

Stan Paddock

Wednesday March 23, 2011

2011-04-10T21:41:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, Stan Paddock, Bill Flora, Frank King, Glenn Lea, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Ron Crane, Judith Haemmerle,Bob Feretich

Visitors: Johann Gunnarsson, Marty Adams and Mike Lewis

It i not often that we get 12 people all in on the same day.

A great deal of fun was enjoyed by all.

Johann Gunnarsson brought in a 1401 program he wrote to run on the two Icelandic 1401 systems.
Van Snyder has typed the program into a PC and run the program. It works very well.

Bill Newman is working on the Connecticut IBM 1401 paper Tape Interface circuit.

Glenn Lea is working on the mounting of new parts for the Connecticut IBM 1402. These new parts were fabricated at the local IBM Plant and in Stan's and other people's garages.

Bob Erickson talks with Jim Strickland and his wife about stories for Jim's interesting story documentation.

Stan

Wednesday March 16, 2011

2011-03-20T21:19:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, Stan Paddock, Bill Flora, Frank King, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Allen Palmer, Ron Crane, Judith Haemmerle

Visitors: Johann Gunnarsson, Stephen Somerstien and several lost Computer History Museum visitors.

Johann Gunnarsson is the leading long distance visitor to the CHM IBM 1401 Restoration room. He lives in Iceland and in the 1960s maintained all of the IBM 1401 computers in Iceland. (2)

Johann Gunnarsson’s son Jóhann Jóhannsson was fascinated with the IBM 1401 and wrote a musical piece "IBM 1401 A User's Manual". This was played on one of the IBM 1401s before it was shut down for the last time. An interesting piece can be seen on http://www.youtube.com/watch?v=whvzDJGt-fk.

A sample of our own IBM 1401 playing music can be heard at: http://www.paddockdrayage.com/IBM1401PlayingMusic.wmv.

Robert Garner and Johann Gunnarsson are shown above in the IBM 1401 Restoration Room at CHM.

To make Tape Drive Three on the German IBM 1401 work right, you have to get right down to the internal problems. That is what Joe Preston is doing above.

Ed Thelen and Bob Erickson continue to work on the IBM Model B typewriter. Why Ed thinks you need a big Tektronix oscilloscope for this mechanical device, I have no idea.

Robert Garner, Ron Williams and Bill Flora have found something funny to laugh about. The Connecticut 1402 still has a lingering problem with the card reader so that must not be it.

Stan Paddock

Saturday, March 12, 2011

2011-03-15T13:30:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Stan Paddock, Judith Haemmerle

Due to technical difficulties, the video portion of this blob continues to be interrupted.

Ron Williams and Stan Paddock continue to work on the Connecticut 1402 card reader. We are getting closer but have not found the cause of the problem.

Bob Erickson and Judith Haemmerle continue their work on the IBM Model 'B' transmitting typewriter. Almost all of the keys will cause the type bars to strike the paper and leave a good impression.

Stan Paddock

Wednesday March 09, 2011

2011-03-15T13:22:00.000-07:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Allen Palmer, Ron Crane, Judith Haemmerle

Due to technical difficulties, the video portion of this blob has been interrupted.

While pictures were taken on March 9th, the camera used to take the pictures has decided to hide. Anyone knowing the whereabouts of the silver Kodak camera is urged to notify your local police department.

Allen Palmer and Joe Preston continue their work on tape drives number two and three of the German IBM 1401 system.

Bob Edwards and Judith Haemmerle continue their work on the IBM Model 'B' Transmitting typewriter.

Ron Williams continue on the read problems associated with the Connecticut IBM 1401 system. Every other card that has an odd number of rows punched will be flagged as an error. For those of you that know IBM 1401 systems, this is a error associated with the 'X' check memory plane.

Ron Crane and Stan Paddock continue to work on the power input to the German IBM 1401 system. The power distribution was as follows.

German IBM 1401, 1402, 1403, 1406, (1) 729	220/380 3Ǿ 50 Cycles	10.85	2,387.00	53.06%
	220/380 3Ǿ 50 Cycles	7.05	1,551.00	34.47%
	220/380 3Ǿ 50 Cycles	2.55	561.00	12.47%
Total of three phases		20.45	4,499.00	100.00%

Ron investigated and found the fans (35) were all powered from lea 'A'.
We moved the fan load from leg 'A' to leg 'C'. The power distribution is now as follows:

German IBM 1401, 1402, 1403, 1406, (1) 729	220/380 3Ǿ 50 Cycles	6.80	1,496.00	32.03%
	220/380 3Ǿ 50 Cycles	7.01	1,542.20	33.02%
	220/380 3Ǿ 50 Cycles	7.42	1,632.40	34.95%
Total of three phases		21.23	4,670.60	100.00%

It does not get any better than that.
Now that the legs are balanced, we will work on the power factor. With the leg load and power factor controlled, the loading on the Pacific power converter will be much lower.
During our tests, we found that two of the linear amplifiers in the converter are not performing up to their full ratings. These will be fixed or replaced from our spares.

With an invitation from Karen Kroslowitz, Bill Newman and Doug Martin visited the CHM warehouse in Milpitas. They were looking for some interconnecting cables for the IBM Model 'B' Transmitting typewriter. Two matching typewriters were found but they were both associated with the stored IBM 1620. While they were offered to us because they were already 'service' status, Bill and Dough did not want impact a future revival of the 1620.

There is a section of the Connecticut IBM 1402 that has been missing since we received the machine. While it is not required for the functioning of the machine, it does expose some electrical and mechanical dangers to the operators.

We removed the missing pieces from the German IBM 1402 and Bill and Doug took them with them to the warehouse to see if any of the stored IBM card machines matched what we need.

The guys found several close calls but only the IBM 1402 from Visible storage had the right parts. These are not available to us as it is a part of the permanent collection.

We had three couples who found there way down the hall and wondered what was going on in the 1401 Restoration room. They got the usual "Data Processing in the 1960s" dog and pony show. They seemed to enjoy it as much as I enjoy giving it.

Saturday, March 05, 2011

2011-03-05T21:02:00.000-08:00

Attendees: Ron Crane and Stan Paddock.

Ron Crane and I have been working on the strange power consumption for the German IBM 1401.
Ron called me up this morning and asked if I would like to come in today when we would not bother anyone else. I said yes.

What we learned:

Both the Connecticut and German machines have 4 Ferro-resonance transformers. 2 in the 1402, 1 in the 1401 and one in the 1406.
The Connecticut machine runs on three phase 120/208 60 HZ power.
The Connecticut machine runs the Ferro-resonance transformers by connecting them between two legs of the input power. (208 volts)
The German machine runs on three phase 280/380 50 HZ power. To minimize the input voltage to the Ferro-resonance transformers, the Ferro-resonance transformers are connected from a leg of the input power to neutral. This supplies each one 220 V instead of 380 V if they were connected leg to leg like the Connecticut machine.
If we determine the power of each Ferro-resonance transformer, we could switch the source to one or more and thereby balance the total load to the German machine.
We also have to determine how the inputs to the Ferro-resonance transformers map back to the input power.

Stan Paddock

Wednesday March 02, 2011

2011-03-05T10:36:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Allen Palmer, Ron Crane, Judith Haemmerle

Guest: Bill Kell; My Father-in-law from Carson City, NV

Having spent most of his career making computers and other electronics work, Bill had little trouble punching his name into a punched card on one of our 026 Keypunches.

Bill had a discussion with Doug Martin only to find out that they both spent considerable time doing support at the same over seas site.

It was a tape drive day. Allen Palmer continues on fixing the brake on the second IBM 729 for the German system

Joe Preston continues to work on the third IBM 729 for the German system. Joe has taken this machine from totally dead to being able to load a tape and I saw it writing data. Now if that data was good data ..........

Frank likes the IBM 1403 printer. When he heard a bad bearing in the IBM 1403 connected to the Connecticut system, he tore into it to get to the bad bearing. That is when he determined the bearing noise came from the IBM 729 directly behind the printer. Frank found the offending bearings and is in the process of replacing the bearings with new bearings.

Ron Crane continues his quest to make the input power correct to the German machine.

While checking power supplies, Ron found the comment above written inside one of the gates. We are going to the CHM staff for a translation.

In our quest to find all of the problems with the Connecticut IBM 1402 card reader, we found one of the transistors was weak. We found a match on E-Bay and bought it. The picture above is Bill Newman installing the transistor inside the bowels of the 1402. We have fixed several bugs in this area but still have at least one more to go.

Judith Haemmerle and Bob Erickson are working on the IBM Model 'B' transmitting typewriter that will be attached to the Connecticut system as an IBM 1407 inquiry station.

Stan Paddock

Saturday, Febuary 26, 2011

2011-02-28T12:17:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Stan Paddock, Ed Thelen, Jim Hunt, Ron Crane

Visitors: Goerner, Matthias (one of our 1401 volunteers) brought in two visitors. After visiting us, they went into the main exhibits and were there until the museum staff told them they had to leave since the museum was closing. Ed Thelen provided automobile transportation to and from the Museum for the three of them.

We also had four museum visitors who found our door open and came in to see what was going on.
They got the informal briefing on the equipment in the room.
============================================

Ron Crane has been studying the 'power factor' for the input power on the German machine. The top picture is a test setup where high voltage capacitors were connected to verify the amount needed to correct the power factor.

To measure the power factor, the current through a leg of the three phase power is connected to an oscilloscope along with the voltage. If they both peak at the same time, you have the desired power factor of 1.

We ran tests on the power going into the Connecticut machine and the German machine. The results are shown below.


German IBM 1401, 1402, 1403, 1406, (1) 729	220/380 3Ǿ 50 Cycles	10.85	2,387.00	53.06%
	220/380 3Ǿ 50 Cycles	7.05	1,551.00	34.47%
	220/380 3Ǿ 50 Cycles	2.55	561.00	12.47%
Total of three phases		20.45	4,499.00	100.00%

Connecticut IBM 1401, 1402, 1403, 1406, (3) 729	120/208 3Ǿ 60 Cycles	14.77	1,772.40	34.37%
	120/208 3Ǿ 60 Cycles	12.20	1,464.00	28.39%
	120/208 3Ǿ 60 Cycles	16.00	1,920.00	37.24%
Total of three phases		42.97	5,156.40	100.00%

We suspect the power factor shift is related to the unequal loading of the three phases of power going into the German 1401. Research continues.

Bob Erickson is continuing to bring the IBM Model B transmitting typewriter back to life. We were able to get a new typewriter ribbon for the machine and installed it. When we plugged it in and tried to type, no ink transferred to the paper. At lunch, Bob figured out the primary problem. The nearest 110V socket to where the typewriter is located is on the back of the German 1401. That machine runs on 50 cycle power not the normal 60 cycle power. So the power roller that drives the print hammers was running at 50/60 normal speed.

After lunch, we plugged it into 60 cycle power and it worked much better. By the end of the day, Bob got almost all of the type hammers to work as designed.

Ron Williams was checking out the basic timing circuits on the German machine.He noticed a waveform that was not correct. While it did not seem to bother the operation of the machine, it was still wrong.

Ron and Jim Hunt found the card suspected of causing the problem. Jim replaced the transistor and the signal got worse! The question of what 'new' transistor matched the functionality of the old transistor spiked the interest of Ron Crane. The second picture shows Ron Crane testing available transistors to see if he can match the functionality.

Keypunch # 3 miss fed another card again while Bob Erickson and I were watching. It does this about one time out of a hundred. Bob and I took the feed mechanism apart and replaced the feed knives with feed knives from the keypunch carcass. Appears to work fine now.

When I arrived to the Computer History Museum on Saturday, I could not access the external employee door or the two doors into the 1401 Restoration lab. I had to get Museum staff to bring a key and unlock the two doors to the 1401 Restoration lab. We left the doors blocked open all day since we could not get back in if we closed them over lunch. We have been told that this issue is being addressed.

Stan Paddock

Wednesday Febuary 23, 2011

2011-02-27T12:50:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Bill Flora, Frank King, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ron Crane

Frank King heard a noise from the IBM 1403 attached to the Connecticut system.

After removing the main cover and other parts surrounding the top blower motor

, he decided the noise was coming from the IBM 729 tape drive behind the IBM 1403.

Frank then put the 1403 back together and started looking for the noise in the IBM 729 tape drive.

Don Luke continued his efforts to build a course outline to teach the IBM 401 internals.

Ron Crane continued his evaluation for the power going into the German 308 volt 50HZ system.

The term Power Factor defines if the current waveform peak occurs at the same time as the voltage peak. The picture below is of one of the three legs going into the German System.

While this leg looks good, the other two legs show a considerable shift in the power factor.

Ron had brought in some small capacitors which he hooked to the first leg. The sum of theses capacitors (25Uf) cut the problem in half. With the installation of three capacitors of the correct size, the load to the power converter can be reduced by at least a kilowatt. This excess power has to be removed from the room via at least another kilowatt worth of Air Conditioning.

(to be continued.)

Robert Garner and George Ahearn discuss some historical publishing regarding early computers.

Ron Williams and Don Luke discuss the old times when the IBM 1401 was considered "State of the Art".

Ron Williams, Bob Erickson and Bill Flora look for a small missing "C" clip for the Connecticut 1402.

Bill Newman, Ron Crane, Bob Erickson and George Ahearn discuss the way they think an old IBM Model "B" transmitting typewriter works.

Stan Paddock

Wednesday Febuary 16, 2011

2011-02-22T21:05:00.000-08:00

Attendees: Bill Newman, Bill Flora, Bob Erickson, Douglas Martin, Robert Garner, Frank King, George Ahearn, Glenn Lea, Joe Preston, Ron Williams, Stan Paddock

George Ahearn and Stan Paddock are shown trying to figure which key hits which type bar and makes which connection underneath the keyboard. This "Transmitting" typewriter will be used as an IBM 1407 attached to the Connecticut IBM 1401 system.

Bill Newman has been given permission to look at some "Transmitting" typewriters in the warehouse in Milpitas. From inventory pictures these have data cables attached. The machine we have does not have same.

The picture above is for one section of the type bars. Thanks to Ron Crane for the high quality picture.

Joe is continuing his work on the third 729 attached to the German IBM 1401 system.

Ron Crane came in and helped up with our documentation of the power used in the IBM 1401 Restoration Room. Ron explained the difference with three phase delta connection and three phase Y connection. Ron explained the functionality of the power converter. Input 208 volts three phase delta 60 cycles per second with the output three phase Y 308 Volts 50 cycles per second. We also determined the power converter is only 56% efficient.

If you are interested in the data, you can find it on my web site at: http://www.paddockdrayage.com/OneAtATime/CHM1401RoomPower.xls

Robert Garner spent time verifying that the work we are performing on our systems is within the scope of what IBM did back in the 1960's. Since he works for IBM, this seems like a reasonable thing to do.

Bill Flora checks out the card reader of the Connecticut IBM 1401 system. This machine has given us problems from the day we first powered it up.

We have identified and fixed several problems and fixed them. We are hoping that we have fixed the last problem.

Ron Williams is checking for:

1. That the fans are operational.

2. That he has chased the last varmint from the machine.

Bill Newman and Douglas Martin are looking on-line to find replacement transistors for the ones we need on the Connecticut IBM 1401 system.

Saturday, Febuary 12, 2011

2011-02-12T20:21:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Jim Hunt

The database for the door locks has changed again. The team could not get in the outside door or the two doors to the 1401 restoration room via the CHM supplied access card. The team entered via the lobby door and the person manning the lobby desk used a key to open the 1401 room doors.

Ron Williams exercised the IBM 1402 readers and punches on both the Connecticut and German machines. Ron pointed out that to not use these functions is much like leaving the machines in a warehouse putting dents in the rollers. (Good Point)

Ron suggested that we do this exercise every week.

Jim Hunt continued his power supply work. He is a bit frustrated by having failures after fixing the unit. Third time is the charm.

Bob Erickson was doing the same type of exercise Ron was doing on the IBM 1402s but Bob was doing it on the IBM 077 collator. Bob is also working on a demo for the IBM 077 that can be used for demos.

Stan

Wednesday Febuary 9, 2011

2011-02-09T21:56:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Bill Newman, Joe Preston, Ed Thelen, Allen Palmer, Ron Crane

Visitors: Allen Palmer's wife and two CHM docents looking for sample punched cards.

George Ahearn, Stan Paddock and Bill Newman outlined the architecture for the IBM 1407 typewriter.

Stan Paddock fixed the CHM wheelchair that he and Ed Thelen broke last week. It was returned to the CHM lobby.

Allen Palmer continued his work on tape drive number two of the German machine.

Joe Preston continued his work on tape drive number three of the German machine.

George Ahearn interrupted the normal date sequence of the time clock correcting it to the correct month.

Ron Crane explained to Stan Paddock, Bill Newman and George Ahearn the complexities of the three phase power being delivered to the German machine. This includes the conversion of 60 cycle 208 volt power to 50 cycle 208 volt power. It was determined that while there are more efficient ways to to perform the conversion task today, it is not worth the effort to make a change.

Robert Garner brought in his laptop so we could view videos of the upcoming IBM 100th celebration.

Stan Paddock

Wednesday Febuary 2, 2011

2011-02-02T22:10:00.000-08:00

Attendees: Bill Newman, Bill Worthington, Bill Flora, Bob Erickson, Douglas Martin, Frank King, George Ahearn, Glenn Lea, Joe Preston, Allen Palmer, Ron Williams, Stan Paddock

Joe Preston is making progress on the third IBM 729 tape drive. It will now automatically :

1. Load the tape into both vacuum columns

2. Bring the head down on the tape

3. Rewind the tape to the beginning tape indicator

This is all perfectly normal.

Now if it did not continue by raising the tape head and unloading the tape..

There is always next week.

Upon occasion, Robert garner will explain how modern computers work. Or how SUN built the first real computer. Or how much raise we can expect at the end of the month.

We had a pair of guest who decided to see the Computer History Museum because their flight to New York was canceled. They were looking for the BABBAGE machine but wondered into out room by accident.

Stan

Wednesday January 26, 2011

2011-01-30T23:52:00.000-08:00

Attendees: Bill Newman, Bob Erickson, Ed Thelen, Frank King, George Ahearn, Glenn Lea, Joe Preston, Ron Williams, Stan Paddock and Judith Haemmerle

Joe Preston has made the third IBM 727 tape drive on the German machine wake up and almost load tape. Getting close to trying to read and write tape.

The IBM 1403 printer on the Connecticut system will pause the ribbon while printing and thereby cut a row into the ribbon. The ribbon supply and take up on the IBM 1403 is simple so that very few IBM CEs have ever had to work on it. That is what Frank King said when he started to work on the IBM 1403 of the Connecticut system

Well if I take it apart, maybe it will look like an IBM 026 keypunch

Well if I can't see what is going on, maybe I need more people on my team.


Well maybe I can get the whole team to see what is going wrong.


OK, maybe I should look at the mechanical drawing to see if I have missed anything.

By the end of the day we think it may be fixed. Since it only fails every 3 to 6 weeks, we should know if it is fixed when we pay our taxes.

Bill Newman and most of the rest of the team have been working on the Connecticut IBM 1402 almost since it came in. It will generate random read checks with a good deck.

We narrowed it down to cards with a large number of punches in the same row. Like 60 or more '9' punches in one card.
At Ron Williams suggestion, a jumper was moved up to the next voltage level. This helped a lot but was not the final solution.

The problem was further traced to the first read station. When there were over 60 '9' punches in a row, the roller was not being drawn all the way to ground.

We examined the brush that is used to ground the roller and found it was worn and not in the proper place. Corrected that and things were better.

We suspected the transistor that is suppose to ground the roller. While we did not have a ready source for the transistor, we bought a silicon transistor and wired it in place of the original.
When we ran the test program, we had no errors.
We wired the original transistor back in place.
Failures again.
Bill Newman wanted to make sure it was not the final transistor that was the problem.
He removed the first transistor in the pair and one of the spade lugs fell off in his hand. (See picture above.)
While trying to add a new spade the second and third wires fell off the transistor.
Luckily, we had a spare for this transistor.
We tried it again with the original power transistor and still had errors.
We put the silicon transistor back in the circuit and have ordered a true replacement for the original power transistor.
We believe the random read problem with the Connecticut system has been identified and will be soon corrected. Until the transistor is replaced, the system is usable.

That is if the IBM 1403 ribbon transport unit is fixed.

Stan

Saturday, January 23, 2011

2011-01-30T22:33:00.000-08:00

Attendees: Ron Williams, Bob Erickson Jim Hunt and Stan Paddock.

Work continues on the problem with the Connecticut 1402 card reader. Bob Erickson and Ron Williams examine the power transistor of the first read roll.

Now that Jim has a full time job, his only time he can spare for the CHM is Saturdays. Here he is finding and fixing a problem with a power supply.

Stan

Wednesday, January 19, 2011

2011-01-20T19:58:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Don Luke, Bill Newman, Joe Preston, Ed Thelen and Allen Palmer

Ron Williams, Bob Erickson, George Ahearn, Bill Williams and Don Luke continue working on the Connecticut IBM 1401. The common brush for the first read station was replaced and a test transistor was placed in the circuit. While the machine is doing better, it is still not fault proof.

Joe is continuing to bring the third IBM 729 tape drive on the German machine back to life.

Ed thalen and Frank King continue to do what they do best.

Wednesday January 15, 2011

2011-01-15T23:47:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, Stan Paddock, Frank King, Don Luke, Bill Newman, Joe Preston, Ed Thelen and Allen Palmer

Allen Palmer worked with Joe Preston on the third tape drive of the German system. A problem with the head mechanism was fixed.

Joe went back working on other problems with that tape drive while Allen continued his work on the right reel brake on the second tape drive of the same system.

Ron Williams, Bob Erickson, Bill Newman and Stan Paddock continued to work on the card read problem of the Connecticut machine.

At Ron's suggestion, the voltage of the -20 volt power supply was raised one tap. This made a significant difference in the performance. The errors at the second read station disappeared.

We still had errors reported and they were every other line. Suspect X or Y plane errors.
The two wires were switched to use the first read station to be switched with the second.
Now the characters were not being read into memory correct.

At Bob Erickson's suggestion, we checked the brushes that provide ground to the first read contact roller. It was worn and only one of the two brushes was in contact with the roller.

We are in the process of installing new brushes and will finish the job next week.

Saturday, January 8, 2011

2011-01-09T16:52:00.000-08:00

Attendees: Ron Williams, Bob Erickson and Stan Paddock.

Stan finished cleaning, lubing and re-assembly of the ribbon feed mechanism on the Connecticut machine.

Bob and Ron tried to identify the problem on the German machine. A fast continuous read of cards runs without error. If there is a print between the card reads, there is a read error on the 1402 card reader. To be continued.

Jim Hunt came in and looked into some of our failed cards. He also brought a power supply back to life.

(END)

Wednesday, January 6, 2011

2011-01-09T15:43:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Frank King, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Allen Palmer and Ron Crane

Joe Preston gets up close and personal with the number three tape drive for the German Machine.

Allan Palmer is rebuilding a brake assembly for the number two tape drive on the German machine.

Bob Erickson shows off his skills with the IBM 083 card sorter.

Ron Crane, Dough Martin and others are working on the long term problem with reading cards on the Connecticut machine. We have a program and deck that can cause the machine to fail on demand. We are now trying to identify what part of the circuits are causing the failure.

The IBM 1403 printer on the Connecticut machine has, in the past, stalled the printer ribbon. This puts a series of holes in the ribbon. This situation occurred on Wednesday. We believe it is a weak ribbon drive mechanism. Stan started taking the mechanism apart to find the problem.

(END)

Wednesday, December 22, 2010

2010-12-22T21:51:00.000-08:00

Attendees: Bill Newman, Bob Erickson, Douglas Martin, George Ahearn, Joe Preston, Ron Williams, Stan Paddock, Robert Gardner and Allen Palmer

Visitors: none today

Allen Palmer re-joined us after a long term absence.

Joe Preston continued his work on the third tape drive of the German Machine. He misses Glenn Lea's help.

The rest of us continued to work on the card reading problem with the Connecticut machine. After checking the 20 volt, the 30 volt and the differential power supplies to no avail, we looked at the voltages at the read brushes.

The roller is suppose to ground the brushes when a brush falls through a hole in a punched card.

If more that 60 columns have the same punch in the same row, it is not able to do this. We have seen this on a scope with the advancing width cards.

Bill Newman is looking for replacement transistors for the ones in the 1402 that may be failing.

We ran the same test on the German machine and did not seethe failure pattern.

While I cannot say this is the problem, we will know in two weeks when we get back and try the fix.

Stan

Friday, December 17, 2010

2010-12-18T17:29:00.000-08:00

Attendees: George Ahearn, Stan Paddock

With open questions, George Ahearn and Stan paddock decided to go into the CHM and try to answer the pending questions.

Questions we had were:

1. What happens if the temperature sensing card reports the correct temperature?

2. What happens if we run the cards starting with the 80 punches first instead of last?

3. What happens when the punches go from right instead of left to right?

When we entered the room it was very cold. Way below 70 degrees F.
We ran the PTEST program and go the same results as before.
We turned the cards around for case 2 and 3 and got errors until the number of columns went bellow the thresholds as before.

We pulled the temperature card and soldered all sensors closed. This told the machine that the temperature was less than 70 degrees F.
We ran PTEST again and got just about the same results as before.
We pulled the card (indicating that the temperature was over 95 degrees F and got significantly more errors.

Following the ALDs for the temperature sensors, they control a bias to the memory current controller circuit.
While the temperature sensors are broken, they are not responsible for the errors we are seeing. However, the change in the errors with the cold and hot said we are on the right track.
Next week we will inspect the current control circuit and see if we can find the problem there.

We have found some small devices online that will open and close as the ones in the IBM 1401 are suppose to do. We will being buying a batch of these and update the cards we have in both machines so they work properly.

While we had not used up the time Ann Ahearn had allocated to us, we decided to see if see could start trying to find out what was wrong with the German machine. Much to our surprise, it seemed to work fine.

We ran the PTEST program on the German machine with no reported errors.

Bill Flora said that he could not get the 'ripple read' program to run on the Connecticut machine.

We tried it on the German machine and got the same results.
We ran the cards through the PTEST program and 5 cards were reported with errors.

Next week, we will use the IBM 513 to produce a new card deck for the test.

Wednesday, December 15, 2010

2010-12-18T17:04:00.000-08:00

Attendees: Bill Newman, Bill Worthington, Bill Flora, Bob Erickson, Douglas Martin, Ed Thelen, Frank King, George Ahearn, Glenn Lea, Joe Preston, Ron Williams, Stan Paddock

Visitor(s): Robert Garner had two more visitors and Don Luke had one.

Joe Preston continues to work on the last failing 729 of the German system. He is making good progress. Now the tape drive waits until a tape is installed before it tries to load the tape.

During a demonstration on the German machine, the 1403 printer dropped a column. Frank King came to the rescue and replaced one of the 66 hammer driver cards. He commented how dirty that card was.

Stan pulled all of the hammer driver cards and went outside to brush the dirt off all of them.

When Stan installed the hammer driver cards back in, the German machine decided to stop running programs. As time was running late, we had to leave the machine as it was and we would attack it next week.

Work on the card reading problem with the Connecticut machine, we took a suggestion from Jud McCarthy in Boca Raton Florida. We created a card deck of 80 cards. The first card had a ‘G’ punched in column one. The second card had a ‘G’ punched in column one and two. The 80^th card had a ‘G’ punched in all 80 columns. A program (PTEST) was written that read cards with the I/O check switch off. It would print the data and add an ‘E’ in print position 82 if a card read error was sensed.

If the card had 63 or less ‘G’s, there was no errors. Starting at card 64, more errors and columns started to be missing data.

Another deck of cards were punched but using an “”. The ‘’ has three punches per column instead of two like the ‘G’.

When this deck was run, the errors started after the 25^th card. The errors were sensitive to the number of absolute punches in a card.

George Ahearn suggested the problem might be temperature sensitive. We pulled the temperature sensing card over the main memory stack that contained the three bi-metallic thermostatic sensors. The first is specified to be closed until the temperature reaches 70 degree F. The second opens at 82 degrees F and the last one opens at 90 degree F.

Under testing, the first bi-metallic thermostatic sensor worked as designed. The second (hotter) and third (hottest) failed open. At this time, we had run out of time for that day.

Questions we had were:

1. What happens if the temperature sensing card reports the correct temperature?

2. What happens if we run the cards starting with the 80 punches first instead of last?

3. What happens when the punches go from right instead of left to right?

Wednesday, December 8, 2010

2010-12-17T22:11:00.000-08:00

Attendees: Bill Flora, Bill Newman, Bob Erickson, , Ed Thelen, Frank King, Joe Preston, Judith Haemmerle, Robert Garner, Ron Crane, Ron Williams, Stan Paddock AND George Ahearn

Visitor(s): Robert Garner invited Martin Haeberli, a colleague of his from Xerox days (early 80's).

Joe Preston continues to work on the last failing 729 of the German system.

Frank took a set of brake and two clutches from a spare 729 and re-filled the brake with the required amount of power. Replacing the brake on the right hand tape shaft looks like a major undertaking.

Ed Thelen was checking out the new display area when he found a interesting gentleman who also was checking things out. Ed struck up a conversation with him and he turned out to be Dennis Van Sickle of Van Sickle & Rolleri. They have the contract to do the new display area. He is an interesting guy, said he flew in from Pennsylvania to review the progress to date.

December 1, 2010

2010-12-01T21:56:00.000-08:00

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Glenn Lea, Frank King, Don Luke, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Bill Worthington, Ron Crane and Bill Worthington

Glenn Lea and Joe Preston continue to work on the last failing 729 of the German system.
With some technical help from other members, they found that the neon bulbs that have stopped working can be given a second life by reversing the polarity.

Ed Thelen had decided to work with Doug Martin and clean the dirt off the boards in the German 1401.
Ron Williams mentioned that the timing signals of the German Machine have not been checked for some time.
Ed thought that was important and jumped right on it.
Now the German machine is having a problem operating.

George Ahearn brought in his external garage door keypad that would kill a new battery in 2 hours. That is just the sort of problem Ron Crane, Doug Martin and Bill Newman like to sink their teeth into.
After some checkout, Ron Crane said "I think I know what it is" and disappeared down the hall with the board in hand. He had gone into the men's room and washed the circuit board. When he returned with the board dried, it worked fine. He had noticed some corrosion around one of the transistors!
Good Catch Ron.

The Connecticut 1401 is having a problem reading cards again. Last week Bill Newman, Ron Crane and Stan Paddock read up on how the reading circuits work. Without Ron Williams present, we came up with a number of possibilities that were all wrong. But it was fun.
Today, Ron Williams, Stan Paddock, Doug Martin and Bill Newman worked on the problem some more.
Ron Williams showed us how to switch two connections so the first set of brushes is switched with the second.
Doug Martin entered his first program into memory that prints out cards that fail.
This showed that the problem is not associated with just one set of brushes.
We will be working on it again next week.

Wednesday November 17, 2010

2010-11-18T22:07:00.000-08:00

Attendees: Ron Williams, Bob Erickson, George Ahearn, Stan Paddock, Glenn Lea, Douglas Martin, Bill Newman, Joe Preston, Ed Thelen, Bill Worthington

Glenn Lea and Joe Preston continue to work on the last failing 729 of the German system.

While trying to use the neon lights for trouble shooting, it was found that the majority of the neon bulbs are no longer working. Something to do next week.

While running the tape demo on the German machine, Ed Thelen noticed the right hand take u reel was performing in a very sloppy manner. Further testing identified that the break on the right reel was not functioning even though voltage was being applied.

Again something to do next week.

Bob Erickson, continues his work on the IBM Model B typewriter with avid on-lookers George Ahearn, Ron Williams and Ed Thelen.

Doug Martin and Bill Newman worked on finding the correct connectors for the keyboard switches on the Model B.

There was a celebration for the supporters of the computer History Museum.
Ed Thelen, Bill Newman stayed late trying to figure out the read problem on the Connecticut 1401.
We had several groups of people drop in to visit. The picture above is three of them punching their names for use in BigPrint. The number of people was above 10 and less than 20.

Grant Saviers dropped by with guest. His guest likes the song and dance. One of them stayed longer and got the the complete technical discussion of the hardware.

Before Ron Williams and Bob Erickson left, we were having a problem with the Connecticut machine having read failures. We suspected reader brush problems in the 1402. Later, we discovered that the errors were data specific. We read through all of the documentation we could understand to try and determine what was causing the error.
To quote Ed Thelen,

Newman and Paddock were casting about for problems in

reading cards with the CT machine -

After looking at and analyzing brushes and card errors,

it did not seem to be brushes -

Is there a weakness in the internals of the

CT 1401 associated with reading cards ??

Casting about for what the 1401 does to

read cards and do a read validity check ...

we bumbled into a nice blue notebook

which had significant info ---

I have posted this information (diagrams) at

http://ibm-1401.info/CompLogic.html

we looked a lot at Figure 51 :-))

The link in the index page is near

http://ibm-1401.info/#1401-Processor

We will have to talk to Ron Williams next week to learn the next step in finding the problem.

Monday, November 15, 2010

2010-11-15T23:14:00.000-08:00

On Monday, November, 15^th, the Museum will be holding a special Staff/Volunteer Preview Party from 3pm - 5pm, in celebration of the up-and-coming Revolution Exhibit. Attendees will have a chance to visit Revolution (which will still be a work in progress), sample food from the new café menu, and generally celebrate. For volunteers, this event will also be a mini-volunteer celebration. We will be unveiling the new volunteer board in the gallery.

Those attending were:

Eileen Erickson, Bob Erickson, Bill Flora, Ed Thelen, and Ron Williams.

Glenn Lea, Stan Paddock, Frank King, Don Luke, Mike Albaugh, and Dave Bennet.

Also in attendance but not included in the pictures were Bill Worthington and Dan McInnis.

Saturday november 13, 2010

2010-11-15T11:07:00.000-08:00

Today's attendees were :
Ron Williams, Bob Erickson, Stan Paddock, Ron Mak, Jim Hunt, Bill Worthington and Bill Newman

Ron Mak brought in 20 or so students from his computer classes at San Jose State.
His objective is to show how data processing was done in the 1960's.
This is the second year he has brought his students in.
Presentation of the equipment was done by Bill Worthington and Stan Paddock.

During the day, we had another 15 visitors that dropped in to see the operational equipment.

Lacking a service station hoist, we are forced to lay the IBM Model B typewriter on its back to work on the underside connecting wiring.

Bob Erickson, Jim Hunt and Stan Paddock worked on how to connect to the electrical components.
IBM Model B typewriter is what was used in the IBM 1407 inquiry terminal.
With any luck, we will be able to re-create that functionality again with this unit.

Wednesday. November 10, 2010

2010-11-11T22:22:00.000-08:00

Today's attendees were :

Ron Williams, Bob Erickson, Robert Garner, Stan Paddock, Bill Flora, Joe Preston, Frank King, Glenn Lea, Don Luke and Bill Newman
We had a visitor Nor Burbue from the the CHM Docents.

Bill Newman and Ed Thelen helped Bob Edwards try to understand the IBM Model B electric transmitting typewriter.

Glenn Lea and Joe Preston are working on tape drive for the German Machine. It is good to see Joe Back after fighting a back problem.

With Ron William's help, Frank was trying to remember how to repair an IBM 1401. During the training, the German IBM 1401 decided to destroy another card. Between the two of them, they found and replaced the faulty card. One more card for Jim Hunt to fix.

Norm Burbue stopped by to see what we were doing. Hopefully, he will come back and help us work on something.

Dennis Cassar from CHM Facilities gave us an old artifact that is the basis of the computer term "Garbage in - Garbage out". Note the chad coming out.

Wednesday. November 3, 2010

2010-11-07T21:54:00.000-08:00

Today's attendees were :

Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Bill Flora, Frank King, Glenn Lea, Don Luke, Douglas Martin, Bill Newman and Ron Mak

Ron has some of his SJSC students coming in on Saturday the 13th.

He came in to insure he had name cards for the students (BigPrint) and some example cards to give away.

Ron also gave us source code to a program he wrote when he was in high school. We punched out the cards after Ron left and ran it on the German machine.

The picture of Abe Lincoln is printed using the text of the Gettysburg Address.

Bill Newman worked with Ron Williams and Frank King to see why the tape drives on the German machine were not working right. Bill found a loose connector on the tape buss chain.

The Computer History Museum had a mass of people on this day. We could not go to any of our normal lunch rooms and had to seek shelter outside.

Don Luke helped Bob Erickson fix a tab problem on the IBM model B typewriter.

Using a CPU intensive program, Ron Williams tried to get the Connecticut 1401 to fail as Stan said it did. Ran all day with no failures.

Stan Paddock

Wednesday, October 27, 2010

2010-10-28T10:30:00.000-07:00

Today's attendees; Robert Garner, Doug martin, Ed Thelen, George Ahearn, Stan Paddock, Glen Lea, Ron Williams and guest Dave Keyes.

A problem with the Connecticut 1403 printer was addresed by Bob Erickson and repaired with the aid of his trusty soldering iron.

Bill Newman brought in some modern motor start capacitors to be installed in Bob Erickson's IBM Model B typewriter. This fixed the problem of the old device trying to smoke us out of the place. After replacing the bad capacitor, Bob returned to finding why the tab function of the typewriter does not work.Bob had a lot of help fixing his typewriter.

Doug Martin, Stan Paddock and Bill Newman researched a mystery connector on the Connecticut 1401. We suspected that this is where an IBM 1407 typewriter would be connected. Late in the day, we discovered that the majority of the wires in the connector are not connected to anything.

Stan Paddock and Bill Newman continue their debugging of the Connecticut 1401 to IBM PC interface.
The second test was stopped by a hard crash of the machine. An attempt to run Big Print had the same problem. We will attempt to recreate the problem next week so we can fix it.

Stan Paddock

IBM 1401 Team at CHM

A wonderful day down at the farm

A special Visitor

Full Restoration of The Connecticut 1401 at the Computer History Muesum

Wednesday May 18, 2011

Wednesday May 4, 2011

Wednesday April 20, 2011

Wednesday April 13, 2011

Saturday, April 09, 2011

Wednesday April 06, 2011

Wednesday March 30, 2011

Saturday, March 26, 2011

Saturday, March 25, 2011

Wednesday March 23, 2011

Wednesday March 16, 2011

Saturday, March 12, 2011

Wednesday March 09, 2011

Saturday, March 05, 2011

Wednesday March 02, 2011

Saturday, Febuary 26, 2011

Wednesday Febuary 23, 2011

Wednesday Febuary 16, 2011

Saturday, Febuary 12, 2011

Wednesday Febuary 9, 2011

Wednesday Febuary 2, 2011

Wednesday January 26, 2011

Saturday, January 23, 2011

Wednesday, January 19, 2011

Wednesday January 15, 2011

Saturday, January 8, 2011

Wednesday, January 6, 2011

Wednesday, December 22, 2010

Friday, December 17, 2010

Questions we had were:

1. What happens if the temperature sensing card reports the correct temperature?

2. What happens if we run the cards starting with the 80 punches first instead of last?

3. What happens when the punches go from right instead of left to right?

Wednesday, December 15, 2010

Stan pulled all of the hammer driver cards and went outside to brush the dirt off all of them.

When Stan installed the hammer driver cards back in, the German machine decided to stop running programs. As time was running late, we had to leave the machine as it was and we would attack it next week.

If the card had 63 or less ‘G’s, there was no errors. Starting at card 64, more errors and columns started to be missing data.

Another deck of cards were punched but using an “*”. The ‘*’ has three punches per column instead of two like the ‘G’.

When this deck was run, the errors started after the 25th card. The errors were sensitive to the number of absolute punches in a card.

Under testing, the first bi-metallic thermostatic sensor worked as designed. The second (hotter) and third (hottest) failed open. At this time, we had run out of time for that day.

Questions we had were:

1. What happens if the temperature sensing card reports the correct temperature?

2. What happens if we run the cards starting with the 80 punches first instead of last?

3. What happens when the punches go from right instead of left to right?

Wednesday, December 8, 2010

December 1, 2010

Wednesday November 17, 2010

Monday, November 15, 2010

Saturday november 13, 2010

Wednesday. November 10, 2010

Wednesday. November 3, 2010

Wednesday, October 27, 2010

Another deck of cards were punched but using an “”. The ‘’ has three punches per column instead of two like the ‘G’.

When this deck was run, the errors started after the 25^th card. The errors were sensitive to the number of absolute punches in a card.