Update: Turned out this particular board is just an XT protocol board, with an AT layout and internally-controlled lock lights, and works perfectly but requires a Soarer's converter.
Hello everyone. I acquired a Packard Bell M7US02X keyboard which is apparently a rebranded Korean Sejin M-8700 of sorts. The keyboard seems like it originally had an AT/XT switch which is missing. If I plug the keyboard into a computer (with a passive AT to PS/2 adapter) as-is, I get intermittent flashes of the LEDs, but the computer always reports "No keyboard found" at POST, and will not register any keypresses. One thing I noticed was that I could get the Num Lock to stay on sometimes, but waiting a bit or pushing a key would make it go out. Correct me if I'm wrong, but I think the num lock light somewhat working is an indication that the keyboard is already in AT mode, and at least trying to work, but that's the most I can seem to get out of it.
My first thought was to jump the terminals where the switch used to be to simulate the AT/XT switch, but no combinations of doing that produced any different results, so I followed the traces on the board and realized that two of the terminals for the missing switch lead to places on the board where there seem to be a missing wire and two missing diodes, and the traces just end there and go nowhere. There are also three empty places marked for diodes that are connected closely to the status LEDs.
I have done a LOT of searching and found only a few references to this keyboard's existence let alone any detailed information or schematics. Is there a chance that this one was simply made without these components and intended for only AT or only XT use? Would there be any way to find out without the use of something like a Soarer's converter? I'd prefer not to shell out for one if it won't be a sure thing to get the keyboard working. Maybe something else could be causing the issues? Maybe somebody at some point robbed the keyboard of those missing parts for who knows what reason and putting in new diodes would fix it? It seems bizarre and unlikely to me that someone would remove a switch, some diodes, and a wire from an old keyboard, but the keyboard came from a hoard of stuff left by a relative who was a little... eccentric.
I made an album with pictures showing everything the best I could. Any info would be very much appreciated. I really love the layout of this keyboard and also the feel of the Futaba key switches, so if I can get it working without too much trouble that would be awesome.
https://imgur.com/a/Qz2acy1