Those switch capacitors are ridiculously cheap (like 100 for about 2 bucks or so) so just order a ton of them. Most likely they are the issue like frunch says. Most standups in this era Bally used them to detect the short fast hits, I doubt the bank shot would have been one of them since it's so far up the playfield and over a bumpy path of downed inline drops so the ball would have been going slow enough at that point, but they are really easy to change since it's cut off old solder on new. If you're really lazy you can leave the cut leads long, make a little hook on them, and solder the new ones onto the old leads.