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DEC Laboratory Modules

m_thompson

m_thompson

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Jul 8, 2014
Messages
2,161
Location
Rhode Island, USA
The Rhode Island Computer Museum recently received a donation of two DEC Laboratory Module chassis that are both full of modules. This was DEC's first revenue generating product from about 1961. We are in the process of documenting the modules, and will configure one chassis as a binary counter for a demonstration.
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Neat.

I have acquired some R modules recently - and a few backplane connectors - so I was planning to ‘lash up’ some of the early (i.e. simple) projects from the laboratory handbook.

Dave
 
m_thompson said:
The Rhode Island Computer Museum recently received a donation of two DEC Laboratory Module chassis that are both full of modules. This was DEC's first revenue generating product from about 1961. We are in the process of documenting the modules, and will configure one chassis as a binary counter for a demonstration.
r4FwBIbzPGOc5PcJtjVZNgl67YerqgvlW0O1hNR9ya4Cy40XrqvdNBPJQf96eavPWXHoPP6RY5Do8hAtXR4WM6KKemNtNVUD06afmYjD1F8tuDJV_zw0s9FRa6clDGIRkg=w1280
Click to expand...
Your image/link gives me a "forbidden" error.

Vince
 
I bought a DEC Type 730 power supply on eBay to power the Laboratory Modules at the RICM. It is two complete power supplies that share a transformer. The capacitors have a date code of August 1960. On the left is a feroresonant transformer and capacitor, probably made by ACME like all of the newer DEC power supplies. At the back are two General Radio Variacs that yield an AC output from 0VAC to 20VAC. Between the transformer and capacitors are two full-wave diode bridges made from 1N1227 diodes. Two of the diodes on the left bridge are open. I will substitute modern Vishay VS-16F diodes for the original 1N1227 parts.

I need to find some mating connectors for the power connections on the back of the Laboratory Modules. Any clues would be appreciated.


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Cinch "Jones plugs".

The mating connector should be "S-308-CCT", a web search for that came up with several sources, none leapt out as being superior so I'll leave it to you do a search and pick.
 
We replaced the diodes in the power supply and connected it to one of the Laboratory Module chassis. We wired a Clock Module and 8x Flip-Flop as a binary counter, and it worked great for about 4 hours. Then there was a loud pop from the power supply and lots of really stinky smoke. Looks like we need to replace the 1.5uF cap in the transformer's feroresonant circuit.

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m_thompson said:
Then there was a loud pop from the power supply and lots of really stinky smoke. Looks like we need to replace the 1.5uF cap in the transformer's feroresonant circuit.
Click to expand...
After two failures and them not being protected and likely PCB they are replace on sight capacitors for me.
 
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