5 years ago unit blew internal fuse. :mad: Repairman changed fuse, but upped amperage from 15 to 20. Unit is now 15 years old. This weekend tried to heat vegetables, but oven gave deep rumble/hum then blew its internal fuse. Replaced fuse with 15 AMP fuse per spec. Buttoned up unit and panel lit up and accepted putting in time. Tested with mug of H2O and growl/hum was followed by blown fuse immediately after pressing start button. Replaced fuse with 20 AMP fuse a la repairman. Set time again and tested with same mug of H2O with same growling hum followed by blown fuse. :confused: No strange smell or signs of arcing inside the electrical/electronics cabinet; only the low frequency growl/hum followed by blown fuse. What's the problem? Bad diode? Capacitor? Transformer? Electronics seem to be OK, but MW power side of electrics seems to be overloading fused portion of system when activated. Advice please? Do you have replacement parts for all the possibilities? Unit is clean, little used, and worked great. It is installed in custom kitchen cabinet and matches other appliances there. Would rather diagnose and repair than replace. :rolleyes: Help, please?