There is only 1 thing that could possibly cause that. If
this doesn't stop the illegal instruction and strange characters appearing on the reset screen then it will remain unfixed until I get a CD setup. The RAM is being corrupted by something, I made a change that hopefully fixes it.
Atleast the debugging additions help figure out the issues that may pop up now and later,illegal instructions must be caused corrupted RAM here.
Cool drive pics, so they dumped Sony with the later design. The only thing that's clearly common is the motor driving chip. On top loader there is the CD DSP and MCU, I'm guessing the Toshiba and Sharp are the equivalents but there doesn't seem to be an easy to find datasheet on those. Too bad about the lasers not being compatible, without a known source of laser replacements I don't think I will ever buy a Z. Not at the prices they go for.
I also have a theoretically working program for improving front/top loader load times (not by much though) but the emulator crashes when I attempt to test it. So I can't even theoretically verify that it works, no hope there. Will wait until I get my own system.
e: see the market forum in a couple of hours