Hi Ian,

5.4V for the 5 volt rail is too high and strange faults may occur. The voltage should only be a high as 5.1V max. May need to look at rebuilding the 5 regulator. Can you try your faulty MPU again in the Dolly Paton machine just to make sure if doesn't flash?

Was the socket on U8 change during the corrosion repair. I would also check for and damage to this socket.

regards Derek

I just thought, i replaced the SDB with a spare that i have and it still didnt work.that should have fixed the 5.4v

the U8 socket was replaced, i have buzzed out all the legs and adjoining solder connections.

i didnt put the whole board in Dolly just the 6800 chips were swapped.

Ian.