Author Topic: Attempting to Repair 1970 Incoterm SPD computer  (Read 6737 times)

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Offline joeqsmith

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Attempting to Repair 1970 Incoterm SPD computer
« on: August 16, 2015, 02:11:18 am »
This is my first electronic computer.   It has been in storage and after I pulled out two IBMs, I thought I would try to get this system running.    A little info on this computer can be found here:

http://www.datormuseum.se/peripherals/terminals/incoterm-spd-20-20

Currently I am checking the main power supply.  This is a switching supply using a large 60Hz transformer for the first conversion followed by a smaller transformer for the switching stage.   

There are at least two bad caps so far.   I suspect the one on the right is 35uF 35V Tant. 




How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #1 on: August 16, 2015, 06:43:39 am »
Replaced all of the output caps and several others.   Put fresh grease on the sinks.  Diodes were all fine but one transistor failed shorted.   It also appears that three of the power transistors had failed.     :'(

I had some better parts for the power transistors but I'll need to order the small one.   For now I am testing it without the first stage transformer and just running it from my small bench supply to limit the power.   Running at a lower voltage, I was able to use a different transistor and try it out.   It seems to regulate with a small load just fine.   It's a start....

   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #2 on: August 16, 2015, 08:04:07 pm »
Video showing the circuit boards and storage unit.   

https://www.youtube.com/watch?v=CDijWQ91JWQ&feature=youtu.be
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online PA0PBZ

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #3 on: August 16, 2015, 08:17:44 pm »
I hope there's any data left on those disks...
Keyboard error: Press F1 to continue.
 

Offline joeqsmith

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #4 on: August 17, 2015, 12:09:18 am »
I'll cross that path when I get to it.  In the mean time, here is part 2.

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #5 on: August 18, 2015, 05:20:24 am »
Stupid TO39 case was over $20/ea.   1970's vintage parts are expensive.   It's getting a better part spec'ed in with a different case for 70 cents.    Hope to get the power supply running this week.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #6 on: August 20, 2015, 01:16:18 am »
New transistors made it in.  Installed one and tried it out with a couple of back to back transformers.   I'll check it on the auto transformer next and make sure it's fine under a higher   load.     

With any luck there won't be too many more problems with it.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline ChristofferB

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #7 on: August 20, 2015, 01:34:45 am »
Wonderful piece of equipment! Hope you get it up and running!
Those vintage parts can be a real pain to get. Have had a lot of fun trying to bring a 70's dumb terminal back alive..

--Christoffer
--Christoffer
Check out my scientific instruments diy (GC, HPLC, NMR, etc):
Channel: https://www.youtube.com/channel/UCZ8l6SdZuRuoSdze1dIpzAQ
 

Offline codeboy2k

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #8 on: August 20, 2015, 06:01:31 am »
Awesome!

I grew up with this tech.. not that Incoterm specifically... but hardware just like it, and sometimes even bigger still..

And just think, now you can get 500 to 1000x the processing power in an Apple watch :)

Waiting to see the blinking cursor and OS boot :)
 

Offline joeqsmith

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #9 on: August 23, 2015, 02:10:41 am »
Red button is a sort of reset.  Sets system to read the lower nibble of each key pressed and stores it into the core.   



How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline AF6LJ

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Re: Attempting to Repair 1970 Incoterm SPD computer
« Reply #10 on: August 23, 2015, 02:39:05 am »
That is so Cool.
Sue AF6LJ
Test Equipment Addict, And Proud Of It.
 


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