I'm hoping someone may have some insights into this, or seen something similar. Our co-op has an Amazon Hunt that is blowing the F11 fuse. The first time it occurred we thought we had tracked it down to a bad coil, so we changed that to no effect. More troubleshooting led us to suspect the transistors for the right drop target bank, specifically the reset ones if I remember correctly, might be internally shorted. We pulled and replaced those and everything worked fine. We played quite a large number of games with no issue, until we came in the next day to find that the banks would not reset when a game was started. Sure enough, it was blowing the F11 fuse again within 5-10 seconds of power on.
This time we took no chances. We replaced all the coils on both banks, and all the transistors associated with them. We also inspected all the ground mods and straps and tidied up any questionable ones. Again, all worked well after this for a large number of games. The next day, however, after a couple of games were played, the drops didn't reset on a new game and F11 was popping again.
The guy who owns the machine is willing to invest in it but we'd like to keep his cost down if we can. We're leaning toward some sort of power supply issue but we'd rather not have him buy one only to find the problem remains, though it may come to that.
If anyone has any thoughts on what might be going wrong here and causing this thing to essentially short out the transistors every few cycles, we'd love to hear them.