Input needed. I have a Williams System 4 (Flash) pinball. I have 2 bumpers and a kicker that stick on during attract, during a game and on the coil test as well as the flippers being operational even when you haven't started a game (I've changed the 4401 but I don't have a spare relay on hand. I popped the top on this one and unstuck it. It went right back to being stuck).
On the bumpers and kicker:
1. Changed all 3 TIP102 and 4401.
2. Changed 7402 and 7408s (tried several spares)
3. Changed PIA (tried 3 different ones with the same stuck on coils)
4. Checked wiring (still stuck to ground with playfield disconnected) Checked coils/diodes anyway - they're fine.
5. New female 40pin connector / reflowed male solder.
6. Cleaned all pins on power supply.
7. Got all game switches working perfectly.

That about covers it. This problem has confounded me. It's not in the platfield since the 3 associated tip102s ground on startup without even starting a game with all connectors from playfield removed.

All I'm left with is a CPU problem, but since these are "special solenoids", they're only controlled by MPU during the coil test, but they're stuck on then too. These are controlled by a playfield switch since they're "special". That switch and it resistor and cap test good. As I said, the problem still exists on driver board with playfield disconnected.

Any ideas or similar problem you e solved?

Thanks!