With a new aftermarket CPU board, the 1 A playfield coil fuse blows straight away; only the knocker and flipper relay come on.

Playfield coil fuse blows at power-up: shorted outhole kicker coil

Cause: The outhole kicker coil had cooked and was shorted.

Checks

• With power off, check every coil diode, then measure the coils for a short (a near-zero reading) or look for a burnt coil.

Fix

• Replace the burnt outhole coil, then find out why it cooked (stuck switch or driver) before running the game.

Systems

• Bally MPU AS-2518-35

Games

• Supersonic

Related tips

• F4 still blows with the playfield coils out of circuit
• Find the coil that keeps blowing the playfield fuse
• Flippers work but no other playfield coils do
• 43 V solenoid fuse blows at power-on only with the lamp board plugged in
• Main solenoid fuse F4 blows (hard short)
• Rectifier board and playfield fuse ratings
• F3, F4 or F5 blows on the rectifier board
• Several coils weak at once: a fuse that tests good but limits current

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