The game plays fine from power-up, but at some point a new game won't serve a ball or the saucer won't kick; then every solenoid except the flippers (and one pop bumper) is dead until the game is switched off and on. New MPU and solenoid driver boards and repinned driver connectors didn't help.

After a while all solenoids except flippers drop out until power cycle: rectifier board

Cause: An intermittent fault on the rectifier board in the cabinet (connections or parts on that board).

Checks

• When it fails, check whether the coils work in solenoid test and whether solenoid voltage is present at the coils.
• Swap in a known-good rectifier board.

Fix

• Replace or repair the rectifier board, and repin its connectors.

The rectifier board carries transformer AC and solenoid voltage; work with the game unplugged.

Systems

• Bally MPU AS-2518-35

Games

• Black Pyramid

Related tips

• No coils work at all though fuses are good and game starts: 43 V not reaching playfield
• 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
• MPU won't boot and driver board test points read low: replace the solenoid driver board
• Solenoid driver TP5 under 13 V
• Rectifier board test point voltages
• Rectifier test point ranges with fuse and rectifier
• Solenoid board 5 V collapses under load: open 12 V bridge on the rectifier board

Source: Pinball Repair help group!! (Facebook group)