This has been driving me nuts, maybe someone can help me find it. So whenever the special is awarding a free game, the credit unit coil which advances the wheel gets stuck. It does not do it on a coin drop, only when special awards a free game. I actually have two coils stuck on since the credit advance coil also pulses the knocker. I am sure I will figure it out eventually but maybe someone knows off hand what switch is set too sensitive.