What do you do with used wirewrap backplanes ?

[leaknoil]

This is just a matter of curiosity but, I saw this auction http://www.ebay.com/itm/PDP-8-DEC-Flip-Chip-Wire-wrap-Backplane-Digital-/170884861695 . I was just curious how you would deal with something like that. Seems like there is no telling what's been wired to what or if changes had been made.

Would most pdp8 people strip it down and start over or go with the part number and try and figure out was different if it didn't work ? Looks like a nightmare.

 

[RSX11M+]

Actually, the documentation exists to fully restore this to a working status. Wire-wrap may not look tidy, but it was a respectable standard for many years and rarely fails.

If it's what one required to complete their project, it would quite a find.

 

[leaknoil]

Not really the wirewrap itself I'm wondering about. It is more how you could ever trust a used wire wrap board of that complexity. Could have been so many things changed for various reasons and things that should have been that weren't. Without some sort of detailed log book with it how could you ever know ? Seems risky to stick boards in it and see what happens.

Almost seems easier to take it all apart and start over.

 

[RSX11M+]

Believe me, a little time with a VOM and a methodical approach and the entire thing can be verified. It's also possible to get help from a detailed examination of the wraps. The wire develops a patina over the years, and it's easy to see when it's been disturbed.

Yes, one requires the information, but that's all available.

Would you believe that in the early years, that was all done by hand? It wasn't until the 80's that I'd learned they converted to a machine based way of making them.

As I recall, the original MIL Wire-Wrap spec was a NAVY one. Maybe someone here can verify that.

Anyway, that doesn't look anywhere near bad enough for a "Do-Over".

 

[vrs42]

This is just a matter of curiosity but, I saw this auction http://www.ebay.com/itm/PDP-8-DEC-Flip-Chip-Wire-wrap-Backplane-Digital-/170884861695 . I was just curious how you would deal with something like that. Seems like there is no telling what's been wired to what or if changes had been made.

Would most pdp8 people strip it down and start over or go with the part number and try and figure out was different if it didn't work ? Looks like a nightmare.

I've bought quite a few of these. Often, you can identify the gear they are out of. Then, as RSX11M+ points out, the documentation exists to reconstruct and debug the original object. Often finding all the right little cards is a comparable effort to debugging the result .

Stuff that I can't identify, I use to store my flip-chip collection. At least they aren't getting torn apart while waiting for someone (me) to figure out what they are supposed to be.

I do have projects that use backplane segments. A flip-chip tester, some projects to re-create backplanes that I don't have yet. There are enough backplanes that come up in a pre-stripped state to meet those needs, though. If I absolutely needed more empty segments, I'd take apart a newer one with a printed circuit board before I'd ruin a wire-wrap.

Vince