We kept blowing fuse F5 (or was it F7) on the main board? Anyways I think it was the big fuse that handles all coils. It sounds crazy, but after 4 fuses being replace, we replaced the night crawler fuses underneath the playfield and I think F7 (whichever powers the nightcrawlers and aux board) and we haven't blown a fuse since. We tested continuity, and the fuses reported fine, but they looked very sketchy. Whatever we did has gotten us through a few months without fuse issues.