[sdiy] Oberheim OB-Xa internal ribbon cables

[Eric Frampton]

Thanks for the explanation. Actually, it’s the *other* end of this cable that I’m having trouble finding a proper name for. I get the IDC 2x13 designation for the connector on the motherboard side, but what of this odd bird on the voice tray side?

https://drive.google.com/open?id=1G0DOyY_PCryc8Z6GtBZI4T6NwgcKpQQQ
https://drive.google.com/open?id=1CgYr-vaVAOBdqJCjequ199Zvxg6J4l4I
https://drive.google.com/open?id=1CgYr-vaVAOBdqJCjequ199Zvxg6J4l4I

Upon further exploration, it really is the connection at the voice tray side that’s the problem, it’s not in the cable itself (yup, Florian called it!) So is it a fair practice to simply snip off 1/2” or so and re-seat the ribbon in this connector (assuming we can come up with a proper snap-on cover for it to keep tension on the ribbon)?

e

>> What are those connectors called? While I’m at it I might as well replace the cap, if they still exist.
> 
> The connectors are known as “insulation displacement connectors”, and you’d probably search for “IDC headers”. I can’t tell from the photo, but the most typical are the 0.1”spaced, double row type. So “2 x 8 16-way IDC header” or “2 x 10 20-way IDC header”. These use the typical ribbon cable which actually has a 0.05” pitch in order to have the same number of connectors in the same width as the plugs - this is definitely the cable in the photo.
> 
> There are also IDC dual inline headers for terminating ribbon cables to chip sockets. These have their uses, but aren’t very reliable in my experience. They do turn up on old gear though. As I said, I can’t quite see, but it looks a bit like the connector on the voice tray end might be one of those.
> 
> The “cap” part on these connectors is usually a cable strip relief. You clamp the cable into the plug in a vise, and then fold it back over itself and clip the strain relief on top to keep it there. It’s possible to use the plugs without this extra bit. I don’t much like the strain relief because I always get confused about which way the plug will finish up pointing when I’m done and then get it wrong. And IDC connectors are pretty much a “one time only” thing - if you screw it up, you’ll be lucky to get the cable out again without damaging the connector. Better to cut it off and do it again with a new one. Perhaps you can get it right, but I never seem to.
> 
> HTH,
> Tom