Unregulated supply at solenoid driver TP5 is below 13 V DC; resets or a dead game.
Solenoid driver TP5 under 13 V
Cause: Bad 12 V or ground connection between rectifier J3 and driver J3 (pre-Xenon rectifier J3 ground pins 2, 15, 16, 18 are suspects), or a failed C23 filter cap.
Checks
- Inspect rectifier board J3 ground pins for heat damage.
- Measure AC volts across C23; several volts AC means the cap is dead.
Fix
- Replace the burnt pins.
- Replace C23; in one case this lifted TP3 from 10 V to 14 V.
Systems
Related tips
- Where the 43 V solenoid supply leaves the rectifier board
- Only about 1.6 V at solenoid driver TP1
- Solenoid board 5 V collapses under load: open 12 V bridge on the rectifier board
- MPU locks with LED on because of C23 or Q20 on the solenoid driver board
- After a while all solenoids except flippers drop out until power cycle: rectifier board
- No +5V on any board and no MPU LED: bad return pin in the solenoid driver board J3 plug
- Solenoid fuse blows even with the outputs unplugged: fault on the rectifier board
- Checking the pre-Xenon supply with the game unplugged from it
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)