I'd clean the switch with a clean piece of paper. Gently pinch the paper between the contacts if the switch and pull it through. A few passes should be sufficient.

Make sure the switch is adjusted properly, and that the screws holding the switch to the playfield haven't gotten loose. Make sure that the ball rolling over the switch's actuator is enough to push the switch closed.

If the switch has a capacitor wired into it, try cutting one leg of the capacitor off and see if that gets the switch working. Either way, if the switch has a capacitor, I'd change it for good measure. Also, gently tug on the wires going to the switch to be sure they aren't loose or hanging on by a thread.

Are any other switches not working?

Whoops, i should have read your post more closely!

Take a close look at the bank shot target, make sure the wiring is correct going to it. Also make sure the diodes on that switch and the B lane switch aren't touching anything they shouldn't be, and that they're firmly attached to their respective solder lugs. Make sure the solder lugs on the bank shot switch aren't touching each other or anything else nearby, as well. I'll have to get a look at the switch matrix diagram, that may help us narrow the possible culprits. (I got the diagram, I'll attach it)

Did it just start doing this recently?

Screenshot_20180908-223844.jpg

I do see here that the bank shot switch (aka "in line back target") has a capacitor, and is in the same switch matrix row as the B rollover switch. Cut one çapacitor leg off the bank shot switch and see if that fixes it (granted that everything else looks ok)

575072596.png

Definitely. It would still work ok with the cap clipped, but the cap is there to help register quick, short hits on the switch. Looking over the switch matrix, it appears the "DELUXE" targets also use those caps, as well as the pop bumpers, and a rollover button (probably the one up the left side of the playfield). So if you're going to order a cap for the bank shot, you may as well order some extras for those other switches too, since they're likely to fail sooner or later.

Good luck!

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.

Good stuff!! Enjoy your Eight Ball Deluxe--that's a game I *will* add to my collection one day. Such an awesome game!

Well, if you ever decide to sell this one, please let me know!

Check your coin switches, I'll bet one of them is stuck. Looking at the switch matrix, you have to pencil in the coin switches which are not shown because they are on the cabinet schematic but are still part of the matrix, If you have a stuck coin switch and you knock down the matching 1,2, or 3 drop target, rolling over the B rollover will give you the bank shot.