Wow! I've never seen a fuse do that before!
Just asking a silly question, is the correct SB fuse in place?
If you have a DMM with continuity setting, you can buzz the tracks from the fuse connector to make sure they are OK..
I can only think that heat - and lots of it caused an issue like that. Are you getting the correct voltages?
We gotta stop meeting like this Marty!!! I thought +1 about fuse rating but checked and is ok. I buzzed tracks and ok. A sparky said to me poor connection can cause such heating but he's no pinball tech. Tha's why I'm thinking about improving the connection with a wire as opposed to the track alone. The pcb has one of these on the other end of the fuse holder see picture. Unsure about voltages as the moment
Yeah, if the connection is poor then this can cause such a problem, as basically the same current has to run through a smaller area hence heating it up more than usual. I would try the wire.
I'd run another wire from the fuse holder to the corresponding pin on the connector.
The burnt track would not be a suitable conductor of current from the fuse to the connector..