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debug extender cards and Unibus Edge connectors

T

thephysicist

Experienced Member
Joined
Mar 13, 2021
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69
Location
New Mexico, USA
I recently acquired a DEC PDP 11/44. Before working on the cards I would like to get an extender card. Otherwise debugging any defect would become even more cumbersome. So 2 questions:

a) does anyone have an extender card to sell?
b) any ideas if it's possible to get the 36 pin edge connectors for UniBus? Searching this forum I only found som recent Omnibus discussions.

Thanks
Michael
 
Douglas electronics used to sell extender boards. They are passive so they work in unibus, omnibus and qbus. The connectors are made by ECS, but you need to by big quantities. I think user @gnupublic still has some ECS connectors for sale. If you don’t want the real deal EDAC and Sullins make 36 pin connectors with 0.125” division that one can use with some tweaks. Actually Douglas Electronics are using EDAC.
 
If you don't mind building your own, then check the thread: https://forum.vcfed.org/index.php?threads/flip-chip-extender-project.74972/ and Joerg's site page: http://retrocmp.com/tools/dec-flip-chip-extenders

Specifically my post here: https://forum.vcfed.org/index.php?threads/flip-chip-extender-project.74972/#post-966701

Bare Hex boards are available, scroll to the bottom of : https://retrobrewcomputers.org/doku.php?id=boardinventory

I bought 12 ECS connectors and one dual and one quad board. You can see pictures on the post above. They work great in my BA23 PDP-11. It was 9 days total from my email to Todd with the order to the day the USPS delivered and this was during Christmas 2020 when things were royally screwed up at the USPS.

Douglas still sells the boards, too but they do no have a hex board listed. You would have to use a quad and a dual. With connectors the dual is cheaper at Douglas https://www.douglaspcb.com/index.php/6-de-77.html @ $20 vs $45 for the PCB and two ECS connectors from Todd/Joerg. But the quad is cheaper - Douglas $90 https://www.douglaspcb.com/index.php/6-de-8.html vs Todd/Joerg @ $35+$40 and the hex is still cheaper from Todd/Joerg @ $42+$60 vs $20+$90 from Douglas. But perhaps getting a dual and a quad is more flexible. Just depends on if you like soldering all those pins :oops:

And if you're really into DIY then on Joerg's page there are the Gerber files so you can order your own boards. The ECS connectors are still cheaper from Todd or someone else that has a supply. ECS still makes and sells them but they have a minimum order of around 300 which is beyond most people's capability.

Anyway. Just some more choices to think over.
 
Last edited:
The ECS connectors are approx $15/$16 with a 100 minimum quantity order from ECS themselves. With a 5 to 6 week lead time.
 
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