IBM 1130 Restoration at TNMOC in 2016

24th September 2016

• I am trying out a new 10A Variac to replace the 5A one I am currently using. The big advantage of having the bigger unit is the printer can be powered again. Due to exposed terminals I have put the variac in a box with a power socket. Initial tests show the peak current used is 9.2A, so it should be OK.
• The system has not been on very often due to other activities in the museum.
• I was contacted many months ago by an ex commissioning engineer who used to test the IBM 1130 in Scotland. He has been trying to get down to see our system since then and we have finally got a date of Sunday 9th October.
• I decided to give the 1442 card reader a clean to make sure it was good for his visit, however when trying the system again I got a card jam resulting in one of the belts snapping... only the second big fault since we received the system. This was a major blow as I had no spare belts.
• With only the IBM part number available (which I could not look up) it looked unlikely I could get a replacement but after many hours searching the net I finally discovered the type of belt I needed and to my surprise, it was still being made. In fact IBM decided to use very common XL timing belts.
• I also discovered that of the 11 different belts used (16 in total), I could identify 7 and still buy 6 of them, including the one that snapped. One belt (used 3 times) remains elusive as it uses a different pitch for the teeth which I can't identify yet.

1st October 2016

• I fitted the replacement belt and manually fed cards until everything looked OK. I then successfully read several decks of cards.
• I tried the console printer test diagnostic and confirmed the console is not working properly (it is not printing the correct characters). I tried to exercise it for 20 minutes but it did not improve. This is the typical result when not used for some time, the oil and grease go off. I will need to try and lubricate it before next weekends visit but it is a very specialist art.
• Also the platen appears to have a problem causing it to spin when line feeding. There appears to be some kind of locking mechanism at the end which I cannot figure out yet.

2nd October 2016

• I investigated the console printing issue and discovered the wire tape controlling the type ball rotation had come off the left hand pulley. I refitted it and on testing again the console was printing correctly. I then lubricated a few areas and the return mechanism was also working now.
• The platen still stops line feeding but a tap on the right hand side seems to engage the clutch again and line feeding starts again. I may need to take it apart to see what is happening but for now it works well enough.

10th October 2016

• Saturday was spent cleaning and lubricating the 1132 line printer and by the end of the day it was performing very well. It still has the issue with printing the wrong character sometimes in that last 10 or 15 columns, but it has always done this.
• I was exorcising the line printer without a ribbon so it did not ruin it. It was clear by the fact it still printed on paper that there is a lot of old ink in the print roller brush, which fits below the print drum and cleans the drum as it spins. Several squirts of WD40 on the print drum has loosened the ink to the extent that by the end of the day it was still printing legible characters in the first 80 columns. It may take many more prints to clear the brush of old ink.
• On Sunday I had a visit by Alex Dillon, who had travelled down from Scotland. He worked at the IBM Greenock factory in Scotland and commissioned 1130s after they came off the production line for 2 years (1965 -> 1967). As our system appears to have been built in 1968 he did not work on our system. He concentrated on fault finding the 1131 CPU and spent many a day behind the 1130 finding wiring and board faults before the systems were shipped out to customers throughout Europe and the Middle East. He said the system was so popular that he was working 12 hour shifts, 7 days a week for a lot of that time to keep up with production. He was still able to read the logic diagrams and passed on some useful info, especially what each of the 6 modules in the back of the 1130 was used for.
• We also ran a few diagnostics from cards and he was really thrilled to be able to see an 1130 running again after so many years. He did spot one possible issue; When the system is powered on it should do a full reset of various stages which should leave the display almost blank. This appears not to be working as intended so is something to investigate sometime. It does not appear to affect running programs though.
• He was also impressed with the rest of the Museum when I took him around.
• The only thing left to check is the disk drive. This will need careful inspection and cleaning before attempts are made to load a cartridge.
• So, apart from the drive, the system is now back to working as well as it was when the main restoration was completed. And the new 10A variac is working very well.

5th November 2016

• Had a problem with the rotate tape today. This is a flat wire that rotates the golfball to the correct character position. This has come off the right hand tension wheel in the past but now appears to be damaged causing it to come off frequently.
• I found a replacement tape in some Selectric spares I bought off ebay a few years ago, but fitting it is proving difficult as the manuals don't really explain what to do. I did watch John Robertson refit one when he got the printer working a while ago, so should be able to do it.
• I also noticed the plastic tab pivot mechanism is cracked (a common problem) so I need to source a replacement as I don't have any spares. The after-market replacements are metal and much more robust.
• While trying to fit the rotate tape I also noticed the plastic tilt cam is also cracked so I will need a replacement for that as well.
• Both of the above parts will need to be sourced from the USA as there are no Selectric parts companies in the UK and the bits I need only crop up on ebay US.
• The 1132 printer continues to work well and still printing without a ribbon, so there is still a lot of old ink on the brushes used to clean the print wheels when they rotate.