When a board is sent to me for low voltage problems I always replace every Electro cap and bridge.
Out of every five of these boards I do I find at least 2 that have a faulty C4 capacitor. ( I test every cap with a cap meter that i pull out just to see how bad they are)
C4 is a 100uf capacitor and i often find them to be down between 40 to 60 Uf. You can also bet that if C4 on the driver board is crook then C31 on the MPU board will also be stuffed.
I also change J114, J115, and all headers for the G.I.s
My opinion is if you are going to pull the board out and replace a cap and bridge then you may as well do a major service. some of the components may not need replacing yet but it will save you on future hassles.
In most cases after I overhaul the power driver board the customer notices that the lamps for the playfield inserts are brighter also.
