Test EPROM: the least an MPU needs to run it

A free test EPROM for Bally and Stern MPUs runs with only +5 V and +12 V, the clock chips U15 and U16, the 6800 at U9 and the test EPROM (2716 or 2732) in U6. RAM, game ROMs and PIAs can stay out. It toggles every PIA output once a second and keeps running whatever fails, unlike the built-in test that stops at the first fault.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• Setting up an MPU for the test EPROM
• ROM and EPROM types used on Bally MPUs
• Stern games from 1980 on need an M-200 MPU
• Jumpers for a -35/-133 MPU running two 2732 EPROMs (U2 and U6)
• 5101 RAM speed grades and which MPUs need what
• Set a -35 MPU up once for 2732 EPROMs instead of re-jumpering per game
• Testing an MPU in the game with only J4 connected
• Using the test EPROM memory test

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)