Pin sockets

At GTE I used to work on Fairchild Sentry IC testers like this Sentry 21:

The test head of the Sentry had pin electronics cards arrayed around a circle:

source: https://caeonline.com/buy/final-test/schlumberger-fairchild-sentry-21/9267919

Here is an interesting paper on testing the Z-80 with a Sentry 610:

substack: https://mtsi.substack.com/p/testing-the-z80-chip-with-a-1970s
 

article repeated here: https://mitsi.com/case-studies/z80-chip/

One thing that were used on the pin electronics cards were small reed relays, either Zestrons:

source: https://www.ebay.com/itm/296449132308

or Coto relays:

source: https://www.ebay.com/itm/394476842759

The reed relays were also used on "performance boards" which were the interface between the test head and the device under test - the relays were usually used for applying loads or power to a pin.  

One thing with the reed relays, they weren't soldered onto the boards, we used small pin sockets like these:

I was able to buy a bag of them from Electronic Goldmine (G22786 sold out ?) a few years ago but I *think* they may still be available (at a price) from Digi-Key or Mouser - made by Mil-Max, the socket people.  I'm afraid I've misplaced my notes on the part numbers though and since I still have hundreds of them left I probably won't be buying more.

These sockets work well with a much lower profile than a regular IC socket.  The one thing is that you must resist the urge to flip the board over and trim flush or the pin socket will be ruined.

Here's a recent board where I used pin sockets, the VE3DNL Marker Generator prototype:

The VE3DNL Marker Generator kit page: http://wb9kzy.com/ve3dnl.htm

It made it easy to change IC vendors for the 4060 chip or change crystal frequencies.  It is harder to get the IC pins aligned to the pin sockets compared to a regular IC socket though.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm