Hi everyone. I'm wondering if anyone has some insight into a weird problem I'm observing with an Apple 1 replica build.
I have recently completed an Apple 1 build using an open source board and managed to get it working well, passing memory tests etc. However I've only been able to get it running using a Synertec 370-6502 CPU. I've tried a MOS 6502, a MOS 6502A and a Rockwell R6502AP, and although the terminal section works as it should with any of them, hitting reset with all but the Synertec doesn't get the computer section running.
I'm wondering what could cause this build to be so picky about the CPU? Could it be that the specs of the Synertec are slightly different from the other processors and something marginal with the other components allows the board to work with it, but not the others?
Of course I can just keep the Synertec CPU in place and have a perfectly running board, but I'm curious as to why that one works and the others don't.