The SAME exact thing happened to the Headmaster I had, years ago (~2003/2004?). On mine, that metal shield was loosely taped-on (with electrical tape; sloppy), IIRC, and it must have popped out during shipping to me - causing the short. Blew the fuse as soon as it was powered up the first time...then again, etc. Had a friend that opened it, diagnosed the cause, and zip-tied the hell out of that thing till it stayed put for good. All was fine afterwards (sold it a few years back); hopefully that's also the case here.