Already made some progress today. Replacing all the badly corroded fuse holders fixed my power problems. Further on, I realised that the fuse on the monitor chassis was also dead, and someone had tried to replace it with tin foil. Put in a new fuse there as well, and the monitor came back to live (white out though, but still ..).
A closer investigation of the game PCB also showed that the prev. owner had inserted the daughter board the wrong way. Fixed that, and straightened and cleaned all its pins in that process. Now the game was playing blindly, with only the monotone invaders sound to be heard. Taking another look at the daughter board, I found a loose jumper wire - now all the sounds are back, but still no picture.
Lots of fun, but I fear I am stuck now without the schematics for the chassis and, ideally, also the PCB.
Martin
