I have a CDTV with a keyboard that I haven't gotten around to use until now. I found out that the 5 pin DIN connector had a broken pin so I decided to replace it.
I've attempted to replace the connector with a modified ps/2 connector (twisted out the 6th pin and snapped the plastic key bit).
Right now it's a bit of a hacky job with temporary splice connectors to see if it works. I've done the following connections (see attached diagram):
C12 connector on keyboard circuit:
RED - GROUND
WHITE - DATA
YELLOW - CLOCK
ORANGE - +5v
Case Ground -> Connector Shield Ground
So on power up, the keyboard's caps lock key blinks once as usual. However, once it gets to AmigaDOS a constant stream of apostrophes is typed (raw code 00) (no, that key is not stuck - even if it was, I would still be able to type other characters). Pressing keys on the keyboard does not do anything, including the reset combo. Pressing caps lock works (light on/off) but then after five presses or so it stop to light up. The '`' stream continues indefinitely nevertheless.
To test whether the keyboard actually works and that the MCU is not fried, I tested it with my A3000 (I just swapped in the cable from the A3000's keyboard). It worked fine on the A3000.
I also decided to try the A3000's keyboard on the CDTV with my hack cable and the result was the same as with the CDTV keyboard, a series of never ending '`', and no other keys responding, including reset combo.
So this tells me the keyboard is fine. It's something else that's gone amiss.
I swapped around the CDTV's odd and even CIAs and that didn't make a difference.
So I'm beginning to guess that either my hacky connection is wonky or that it's something between the keyboard port and the CIAs that's causing an issue.
Would it be worth replacing both CIAs with completely new ones? I've got a few donor machines I could pull those out from. FWIW I've tested the CIAs with Amiga Test Kit and everything passes.
Does anyone have any suggestions on what could be wrong?
Thanks