Omnikey Woes

[hellothere]

I have an OmniKey 102 "blank label." This keyboard is from the same era as the Gold Label, but it just doesn't have a label and it's more commonly found with white Alps. These keyboards also have just an AT/XT switch, rather than the DIP switch that's on newer

The keyboard just doesn't work. No lock lights ever come on. No keys register.

* I've tested with the original cable with a known good 5-Pin DIN to PS/2 adapter. Nope.
* I've tested with a different, known-good, OmniKey keyboard cable and the above adapter. Nope.
* I've tested with a different, known-good, OmniKey keyboard cable, the above adapter, and a known-good PS/2 to USB active adapter. Nope.
* I've tested with a known-good external TMK adapter. Nope.
* I've tested with a known-good internal TMK adapter. Nope.

I've tried all of the above with the keyboard switched to AT and XT. I've made sure power was off when connecting the 5-pin DIN to PS/2. I also made sure to only flip the AT/XT switch when the computer was off. I've tested the USB adapter and external TMK with the computer turned off and when the computer was on.

Other than a couple of partially lifted pads for the keyboard keys, which I did test for continuity, the only other repair was replacing a missing LED. I also do get continuity from the keyboard header pins to the onboard controller chip(s).

Any suggestions on what to test? I'm not an electronics person. I just have a multimeter.

[Polecat]

I'd suggest swapping the EPROM. That's a free, non-destructive test, and has fixed at least one other Gen1 Northgate here:

viewtopic.php?f=2&t=25844&start=30

Note that some versions of the Gen1 Northgates used a 24 pin EPROM in a 28 pin socket. That's legitimate, but very important to have it positioned correcly in that case! There might be a jumper wire or plug-on jumper to select the EPROM size if you change from one size to the other. And there might be different EPROM versions for the different PC board versions. I don't know if there's anyone left who has that information.

If that fixes things you can burn a copy and put the original back where it came from. EPROMs are not particularly trouble-prone, but they can get erased if the sticker is missing and the window gets exposed to UV light. That's how you erase them on purpose to reprogram them (the E in EPROM is for Erasable).

[hellothere]

I forgot about that thread! Thanks very much.

I currently have a much newer OmniKey and several other Focus-branded keyboards -- including one parts PCB, IIRC. I'll see if any of the EPROMs match.

The sticker on the EPROM on my broken OmniKey is intact. Ever since you mentioned that awhile back, I've been making sure to cover up anything that even slightly looks like a window on the chips.

[Polecat]

It probably needs to be from a Gen1 Northgate, and possibly from the same PC board revision. But it won't hurt to try. Most likely the key map will be mixed up, but if it does *something* with a different EPROM you've probably found the problem.