I acquired a non-working Apple III over the weekend from VCF SE. It is surprisingly clean (I think the just-previous owner really cleaned it up) but as advertised, it does not work.
Power is good- I get 5v, 12v, everything there tests fine. It has a 12v 128k RAM board in it. I have removed all the chips and reinstalled them, checking for proper positioning and bent legs. I didn't find any problems, and none of this affected the screen output. I've even moved around the RAM (within the same bank only, it has a mix of 8k and 4k chips).
When I turn it on with everything installed, I get this screen.
If I remove the memory board, I get this screen, but it's not static- the dots move around like a TV tuned to a dead channel.
Has anyone troubleshot a III before and know where to start? The service manual doesn't seem to be much help- it says replace memory board or main motherboard. Real helpful...
BTW, it does the exact same thing without the CPU installed, so I don't think that's even running. I think the screen is black if I remove the ROMs.