I started off with the power supply board, replacing the main filter cap for the 5 volts, and replaced a few pin headers, in particular the one for the 5volt supply to the MPU. The power supply seemed to be working fine as it was so not much else was done to it at this stage. Though I might replace the two rectifier diodes a bit later on when I do the full resto.

Next was the master driver board. I had to replace a few of the solenoid drive transistors, I used TIP102s to replace them, plus I changed their pre driver transistors as well. Also I discovered later that one of the 7408 TTL ICs had to be changed when I still had a coil still trying to lock on (outhole coil). Several of these ICs had already been replaced before at some stage, as they were in sockets.  Another thing I decided to do was to replace most of the 27 ohm resistors for the lamp matrix, even though they were working, just to make it look neater. Several dodgey pin headers were replaced also.