Quoted from JiePieWie:
I've checked a *lot* of connectors on the powerboard and all the voltages were within the limits. I also checked all the coils and measured them and that also was within the expected range. When the 6A fuse arrived i first disconnected all connectors but J5, installed the fuse and turned it on. Nothing happened Then i connected all the rest (J1 -J4) and switched it on after each new connection. In the end nothing happened and until now it's looking good. I haven't played a real game yet because i am cleaning all the playfield parts but a manual run-through showed all bumpers, flashers etc were working.
I did notice that the score-display is 'bleeding' (see attached image) that wasn't there before. Could lowering the voltage on T2 from 190V to 170V help? This was suggested on another forum..[quoted image]
That's good news. It's always nice when it's a simple fix. But, and you have probably figured this out already, once you start playing it, don't be surprised if you find little bugs and quirky behavior, especially since this game has not been played very much for a long time. I would still seriously consider re-working the connectors, and maybe start with those displays. Lowering the voltage is a good thing. Those connectors at the displays can cause some strange issues on the displays.
It's not hard to do them, once you get a feel for doing it.
Did you pull that Driver board from the backbox and check the connectors and traces on the back of it?