This has really got me stumped. I've tried isolating the head box from the cabinet but the problem remains. The same lights still remain off on the playfield when the head box is isolated and vise versa. Occasionally they come back on but only for 10 seconds or so then they're gone again. I've been over the underside of the playfield and inside the backbox looking for anything out of place or touching so many times that I'm starting to see them in my sleep.
 I don't think its dodgy batch of globe holders either because there are three different types of holders involved, they all went at once and they all come back on together.