I am a newbie to home pinball repair, but I am handy and have an ohms meter so going to give it a shot.
As the title says I have a 1978 Williams World Cup that uses System 3. Based on my research so far it looks like it has all the original parts, so no board upgrades or anything.
It was last switched on about 25 to 30 years ago, at that time it made a pop noise and then basically stopped working.
The current state of the machine, when you turn it on, the back glass lights and play field lights come on.
I opened up the machine and noticed the F2 fuse is blown (it's a 2.5amp slowblow) along with damage to the circuit pathway.
Tracing the path I found severe damage to connector 3J2 on the board (3P2 listed on the power supply board connectors?).
I don't think I am going to have the board rebuilt. I can buy a replacement for about $100.
BUT I don't want to drop it in without fixing the problem that caused it in the first place. I am a little lost on where to start troubleshooting.
I have the original manual and circuit diagrams that came with the machine. I am not familiar with how to read them very well, so I am hoping someone here can give me a few pointers on where to start troubleshooting. I have attached what I think are the relevant pages from the manual and diagrams.
Any thoughts or guidance based on experience with these machines would be appreciated.