Quoted from frenchmarky:

Anybody have any tips on drilling out or picking the front door lock on a Bally 873-A? Dated 1972. I got it fixed up years ago but then much later it conked out and I never got back to it until now. Went to grab the key from up top, or on the top door ledge, or in the lock, or in the coin tray and I was sure it HAD to be one of those places or maybe I stashed it somewhere (I wouldn't have a reason to though) or it fell around there someplace but it is just plain gone and I had to give up the search. I figure these must not be that easy to pick and it's okay if I have to drill it. And then in any case, get a new lock and key. It's the vending type lock where the end of the key is like a hollow cylinder. Thanks!