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by William Dromgoole
- 07/28/2016 08:51
At the May 7 workshop we modified one of the Univac 1532 I/O consoles to operate off of 115 volt 60 Hz power.
We did this by removing the 400 Hz transformer and rectifier assy and installing four Meanwell power supplies.
One each of 5 volts and 28 volts and two each of 15 volt. We also made wiring changes needed to still use all the original fuses.
One relay normally energized by 400 Hz had to be bypassed.
When tested it still did not work correctly.
First the model 35 Teletype was all jammed up but after generous lubrication it started to work.
We installed a new ribbon from our spares and the teletype worked ok from the keyboard.
Next we found that the capstan for the paper tape reader had turned to goo.
The paper tape punch always punches bits 0 and 1.
In early June I started building a three phase dummy load for testing the 400 Hz motor generator set we got from APL.
I ordered the proper mating military connectors for the Univac 1219 computer and the dummy load.
On July 3rd I went to the museum and removed the capstan from the I/O console and checked the others we have in the warehouse.
They were all in unusable condition. While I had access to the console paper tape reader I was able to clean all the residue from the gummy capstan and get it ready for a repaired part.
By July 9th I had finished the dummy load and was ready for testing the MG set.
On July 19th I purchased a piece of rubber/vinyl hose with a 1/2" inside diameter and a 3/4 outside diameter.
I cut a short section and put it on the cleaned capstan to test and see if it would work.
At the July 16th workshop we repaired the cabling and cleaned and documented the 400 Hz generator
It was wired for three phase wye 115/200 volts power output.
We rewired it for three phase delta 115 volts output to be compatible with the Univac 1219 computer.
We powered it up and connected it to the dummy load. We tested it at no load, 300 watts ,600 watts and 900 watts.
The rated output of the motor generator set is one KVA.
We tested it using thin jumper wires because we did not have the correct connector between the output jack and the computer power cable.
On July 17th we tried to install the new capstan but it would not fit. The outside diameter was a little too large.
So we set the pinch roller lower and installed the capstan. Reset pinch roller gap to .007 inches.
Tried to read paper tape through unit but it would only move about two inches.
The odd thing is it always stopped at the leading edge of the paper tape holes and the optical sensor with the correct hole pattern in the input register.
After getting the logic repaired we will see if the temporary repair of the capstan is good enough.
Further troubleshooting found three missing cards from the logic chassis.
The first card missing is the driver for bits zero and one of the paper tape punch..
Time ran out so next time will look for spare cards in the warehouse and continue troubleshooting.
Cleaned all the I/O connectors on top of the 1219 computer.
Just about ready for power.
July 25th, Got the proper connectors to connect computer power cable to MG set connectors from eBay.
Nearly read for first power application to Univac 1219.
Still need to install core memory.
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