White screen of sadness

[spirantho]

It looks to me like here (where I've spent hours slavishly highlighting) the traces are all pushed to the right, connecting to the adjacent traces.

You do have a multimeter, right? Time to check those traces.

To be honest, though, if it just suddenly stopped working it's unlikely to be the fault. Scratches on the board don't happen by themselves, so if you didn't do it to break it, then it was like that when it was working...

[spirantho]

I have at least one spare 68000 around here.  If you wind up wanting a replacement, PM me before you go to eBay.

To be honest, I'd say it's very unlikely to be the CPU.
Even though the chances of both CPUs being dead is reasonable, the chances of both of them being dead with exactly the same symptoms is very unlikely.
Best thing to do is to try both CPUs in a known good machine such as an A500.

[spirantho]

i believe all dead CPUs would have same symptoms.

Of all the CPU's I've seen that've died, they rarely die in the same way because they rarely die 'outright'. They just start malfunctioning.

For instance, I have a Commodore +4 with a malfunctioning MOS 8501 (+4 owners will know these probably have a design fault as they die VERY often). The way it doesn't work is that it adds occasional amounts to line numbers. BASIC seems to work, but the line numbers are all wrong.

In the same way, a 68000 can die by losing an address line or tieing one line to another, which can end up with all sorts of weird results... but rarely with just a white screen like this. Especially as the machine responds to the C+A+A sequence.

The progression from grey screen to white screen implies it's starting the boot sequence and then failing before the kickstart loader. That requires at least a partially functioning CPU, as far as I know.