The 1 A slow-blow playfield solenoid fuse blows a few seconds into the boot sequence, at the moment the solenoid circuit is enabled. Every playfield coil measures normal resistance.
Playfield solenoid fuse blows during boot: poor ground on the driver board 74154
Cause: A poorly soldered ground pin on the 74154 decoder chip on the solenoid driver board let several solenoids fire at once, overloading the fuse. Cracked joints on the board's connectors added to the problem.
Checks
- Swap in a known-good solenoid driver board if one is available, to confirm the board is at fault.
- Remove the board and inspect the solder joints on the back of the 74154, especially its ground pin, and on all the connector pins.
- To rule out a shorted coil or diode, boot with the solenoid plug removed, then reconnect it and fire coils one at a time in test.
Fix
- Reflow the 74154 ground joint and any cracked joints, including the connector header pins, on the solenoid driver board.
Games
Source: Pinball Repair help group!! (Facebook group)