Did a flipper rebuild on a Data East Hook not too long ago and afterwards was having a hold problem on the right flipper. Went to check the fuse on the flipper power board and it was fine, but had found some rather shoddy previous work on the board.
The T-800 triac had at one point been replaced and rather than putting back in the board appropriately, they had soldered it on the back of the board along with the heatsink bent in around it. It was pressed up against the cab and, over time, had caused one leg to come loose.

Replaced T-800 triac, TIP32C and 2k ohm resistor. T-800 relocated along with heatsink to proper position on the board.
Wish I had taken a picture of its original state, but I forgot so only have the cleaned up version. Anyway, once on the bench, I’d also noticed one leg of the 2000 ohm resistor in line with that triac had also come off and the issue had caused the TIP32C to short out as well.
I replaced all three components and put the T-800 triac back on the proper side of the board so that it could screw in right on the side of the cabinet where these Data East flipper power boards should.
Unfortunately, wasn’t able to test this one in game as this was for a two flip game and both of my Data East machines are three flips, but got a text later in the evening after the owner had picked up the board that everything was back working perfectly.