Try the inverter section of the unit. If it inverts but does not pass current through from shore or generator power you may only have a blown fuse. Inside the unit is a few control boards. One of the smaller ones has a fuse that if blown will not allow current to pass through. It may pay off to check it first. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7