I'm having a issue with my BG - Not sure what to do.. Basically, it doesn't register that there are any balls loaded. If I shut the game off, flip up the playfield, go into the switch edge test, and manually trip them, they'll work (most of the time). It appears that the whole switch column is experiencing issues. I've tested the diodes, and they all appear to be good.
What else can I do to investigate further?