Vanguard pcb problems

[Laschek]

Is it possible, that the processor causes this problem?

I'd say anything is possible  
Try to find a 6502 on one of your other PCBs, this CPU was used on many games, so chances are you have one on a working game.
Then try that on your Vanguard.

[level42]

Possible yes. Likely....mmmmm.

If it _constantly_ crashes at the same time, I would normally say it's getting a fault in the program (=from the ROMs). The 6502 is doing SO many cycles without crashing on that video.....I think it's not likely that it's the 6502.

The other one you swapped in is obviously bad as it didn't run right ?

Be sure that it is a 6502 and not another variant (check the numbers on the IC).

[Belike]

Possible yes. Likely....mmmmm.

If it _constantly_ crashes at the same time, I would normally say it's getting a fault in the program (=from the ROMs). The 6502 is doing SO many cycles without crashing on that video.....I think it's not likely that it's the 6502.

The other one you swapped in is obviously bad as it didn't run right ?

Be sure that it is a 6502 and not another variant (check the numbers on the IC).

Yes, the other boardset's processors are bad, the game didn't start with them.
I try to find one in a different pcb.

[Belike]

André and Laschek had the jackpot, that was a fu....g power supply problem.
The voltage was only 4.6 and since my friend did a 2 minute repair on that, it's working fine!
I still don't understand, why did it work in demo mode and for 1 game with the broken power supply, but these are arcade machines, so anything could happen!