Ge jes1358wk02 microwave...

Question

ge jes1358wk02 microwave... controls seem to operate correctly....fan runs... capacitor check ok as does magnetron... but no heat... possibly a little on some cycles... suspect problem is with hi-voltage retifier/diode..but cannot check it with my small volt ohm meter... any other suggestions... from internal noise, it seems that high heat comes on momentarily but shuts down while fan continues to run.. ??