This is the current status as I turn it on:
If I try to reset the 6502 I'm generally greeted with a different pattern, even if the most common is the following one:
I can't hide my favorite one is the Atari ET pattern:
Some times after turning it off an on again (an old workaround as you should know... ) I obtain a most common pattern usually tied to bad RAM chip (see the next post for image).
The mainboard was already tweaked with main ICs removed and socketed (again next post for image).
Unfortunately the backside is not in what I could call a "good state" (same as above).
Since the backside status I passed all the connected PIN between CPU/VIA/ULA and related components searching for broke tracks, but they are good. Other things I tested so far:
- 6502, swapped with a spare CPU (1541 is the donor): same results
- 6502, placed the original one in an Apple ][: working
- 6522, swapped with two different IC again from the 1541: same results
- 10017, swapped with the working Atmos one, other Oric 1 and a spare 10017 from ebay: same results
- RAM, tested with Arduino, found two failed and replaced with compatible and tested ones
- ROM, tested with ROM reader, swapped between Oric 1s, swapped with Atoms one: same results
- IC8, IC20, IC21, tested with IC tester, seems good
- Clock, measured I found 12MHZ, 1MHz, 0.86MHz where expected
P.S. I hope I broke no forum rules... In that case, my apologies.