Hi there,
This is my first post to the forum. I hope I'm posting in the right place!
I recently purchased a faulty Amiga 1200 with the intention of bringing it back to life. In the past I have repaired old computer hardware - mostly arcade PCB's. I installed Diagrom 1.3 roms, and hooked up a null modem cable between my Amiga and PC.
The Amiga fails to boot, and throws a "Chk Inst Detected" error. The screen also flashes blue/red.
This error occurs anywhere between immediately after power up, to just after the initial RAM test (which passes).
My understanding is that this exception is generated if a CHK instruction is executed, and fails. The confusion is that (as far as I can tell), the diagrom bios never actually executes CHK. I wondered if this could be a problem with the data bus, but the ASCII text on the serial output all looks okay. I'd expect to see some text corruption if this were the case (or no text at all).
Has anyone come across this problem before. Any suggestions about where to probe? I have an oscilloscope, 8-bit logic analyser, logic probe etc.
Many thanks,
Daryl
