...Possibly.
Cant remember whats on a Bally lamp cct ( this is where Clay came in REALLY handy!), but im guessing that the PIA is decoded by the 4052 multiplexer, this signal i would have thought would go through some kind of buffer chip.. say a 7407 or similar. Normally though there are more than 1 7XXX buffer. If this is the case... and all lamps are off then id look at the PIA and 4052.... if only 1 7xxx buffer then test this first.
Or just gun shot it.. replace both series chips and never be the wiser as to which it was
