Help With 1981 Key Tronic Magnetic Reed Board

[Switch Master]

Hello, a while ago I bot a few old keyboards, one of them I can't find much on and it's got me in a bit of a rut. It's got an ibm 3278 layout and a keytronic pcb, but there's no identification anywhere on the thing. (I'll include the serial and pcb #'s in the pictures). The inside of the case and the pcb have spots for an extra few rows of keys, so I'm assuming it's a custom board? From looking around online I believe that it's got magnetic reed switches, but I'm not 100% confident on that. The microcontroller is an Intel P8035L. It also has a key-hole/lock on the side which connects to a speaker&knob, probably to control keypress sounds.

20221001_221021 (1).jpg (483 KiB) Viewed 12221 times

I've mapped the output to the best of my ability, it has a male db9 port with only 5 pins. Can anyone help let me know what my next steps should be in trying to make an adapter for this thing? I've worked with some old posts and made a USB adapter for one of my other old word processor boards but that was just someone else's work so I have no idea where to start.

[hellothere]

viewtopic.php?t=17523 might help.

My opinion is that it's most probably the magnetic reed version.

I swore off tracing keyboard matrices when they started giving me headaches. Someone on this forum should offer matrix tracing service at a reasonable price.

[AndyJ]

That's seriously old school. What do the switches feel like?

Worst case, you could cut the traces and hardwire your own matrix. There are lots of DIY keyboards out there with a forest of wires inside.

[Switch Master]

viewtopic.php?t=17523 might help.

Thank you!!
When I get some free time I'll definitely try to reach out to the OP of that post. I'm up for learning how to trace the matrix myself eventually, I just don't even know where to start at the moment.

[Switch Master]

That's seriously old school. What do the switches feel like?

They feel good, I don't know how to describe keys well but they feel as deep as my model m, pretty smooth to press but there's a bit of a scratchy/squeaky sound on some of the keys even though you can't feel it rubbing or anything.

Worst case, you could cut the traces and hardwire your own matrix. There are lots of DIY keyboards out there with a forest of wires inside.

I'm tempted to just do that, looks-wise it seems fixable though so I'd rather not cut anything if I don't need to. I got another enormous keyboard in the lot that was for a CPT 8000 series word processor, made a converter for it but a lot of the switches are rusted out so I'll probably put new guts in that one before I do any big changes to this keyboard.