Product 45/85
6821 integrated circuit, PIA - "peripheral interface adapter". These are used in pinball machines going all the way back to 1978. Very common failure, especially if there was an over-voltage problem.
Datasheet
Bally E-620-29, E-00630-0029
Williams 5A-8972, 5430-08972-00
All tested good on a Bally MPU board. See the pics below.
