Re: 1977 original apple II restoration (continued)...

["sicklittlemonkey" <Nick.Westgate@gmail.com>]

> The difference is likely just the "random" power up state of the
> DRAMs, which is displayed on the screen.

Yeah, you're right. I was suspicious of one of Phil's startup screens
which is mixed (shows text and GR), but startup allows that, I suppose.

> Upon RESET, the first thing the II does is set a couple of flags in memory

Yes, but both RES and IRQ/BRK use JSR, which is why I mentioned bad
stack RAM being a possible cause. It's pretty much ruled out by the RAM
chip swap, though.

I hope the repeat chip swap doesn't magically solve this, because I'm
kinda looking forward to hearing what is stopping the CPU. ;-)

Cheers,
Nick.