Games start straight into multiball and the boiler door raises and lowers several times, then stops halfway up until the next game. In switch test the boiler trough opto flickers on by itself and tapping the playfield triggers it.

Boiler door cycles then stops halfway: cracked joints on the quad opto board

Cause: Bad solder joints on the quad opto board for the boiler trough.

Checks

• Watch the boiler trough opto in switch test while tapping the playfield and the board.

Fix

• Reflow all the solder joints on the quad opto board.

Systems

• Gottlieb System 3

Games

• Freddy: A Nightmare On Elm Street

Related tips

• Home run opto not registering: replace the opto emitter and receiver

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