I had reset problems on a TZ but this advise goes for all wpc. A good tech guy told me 99.99% of reset problems are connectors. I found after replacing heaps of stuff a connector wire was not making properly until the game/wire heated up.

So I'm not saying br's don't fail but this tech is honest and said all his problems have been connectors. So maybe you can start there. I remember mine was the connector on the right hand side with 2 red wires I think. I'd check for sure but have problems removing stuff on pinballs at the moment 

Good advice Rob, I have repaired hundreds of pins and never had to change a bridge due to resetting. Connectors have always been the issue. Change with trifurcon connectors/reflow solder and or change header pins on the above mentioned connectors. Most people think that changing the bridges/caps have fixed their problem but the removal of the board and re-insertion of the connectors was the real fix.