I have a 1982 Montgomery Ward Model KSA-8283A that keeps blowing the 15 Amp ABC fuse. I checked for direct shorts and cannot locate anything to cause the fuse to burn out. I tested the transformer and checks okay with no grounding of the windings. The input shows continuity also. Is continuity through the magnatron suppose to show straight through after disconnecting all the wiring to check using a ohm meter? This one does but I am not sure what this one is suppose to do. I have never had to check the magnatrons out before this. Microwave runs a few seconds then buzzes and burns the fuse out. One time it tripped my circuit breaker. If this isn't it is there a good place to start checking for a short somewhere? Thanks for your help.