Turning on an ATX PC supply without a motherboard
An ATX supply stays off until its green PS-ON wire (pin 14 of the 20-pin plug) is joined to a black ground wire (pin 13 or 15-17); the square pin is pin 1, with pin 11 directly across. An older AT supply has a real mains switch and is simpler. Switch-mode supplies may not come up with no load, so a meter alone may read nothing.
The supply is mains powered; keep its case closed.
Systems
Related tips
- How the MPU sees the 43 V solenoid supply
- -17 and M-100 boards cannot run 1979-1985 games without modification
- Turning an M-200 into an M-100, or running two- and three-ROM Bally sets
- MPU board test point voltages
- MPU stops before the 7th LED flash (no 43 V)
- Add a ground jumper on every -17/-35 MPU
- Testing an MPU in the game with only J4 connected
- Bench-testing a -133 MPU: swap the R113 diode for a resistor
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)