Helping a friend with a TZ.
The problem, as it was brought to my attention, was that when a replay was won, the knocker going off would cause the machine to reboot. So, I disconnected the knocker, and the game played fine... that eliminated the reset when the knocker went off, but it didn't solve the problem...
We quickly realized that the problem wasn't the knocker itself, it was the vibration from the knocker going off. In other words, any solid bump would cause the machine to reboot. It's particularly sensitive around the head, where a good rap (thinking knocking on a door) on the wood on the outside with cause it to reboot.
I've checked all of the connections and fuses-- I can't find any that are loose. I've followed the wires in the head looking for kinks or frayed insulation, and I can't find any.