The trap door often fails to latch in the up position the first time it is lifted, though both coils work and it eventually stays up.

Trap door doesn't always stay up on the first try: worn lift crank

Cause: Wear in the lift mechanism: the part of the lift arm (crank) that pushes the door up had worn flat, with a sticky plunger and coil sleeve adding to it.

Checks

• Clean the lift coil's plunger and sleeve and see how much it improves.
• Take the unit apart and look at the lift arm where it contacts the door, and check the small door stop bracket is fitted.

Fix

• Clean or replace the coil sleeve and plunger.
• Replace the worn lift crank assembly.

Systems

• WPC Alpha-Numeric

Games

• Funhouse

Related tips

• Rudy's mouth gear has broken teeth: rotate it to use the good section

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