Amana Over-the-Range not heating

My Amana ACO 1860 AW (over the range) microwave is not heating.
It seems everything else works fine.
I located the tip sheet inside under control cover.
Fuse tests OK.
Magnetron tests OK.
HV Transformer tests OK except for Filaments to chassis tests shorted…sheet says they should test infinite.
Does this tell me that the HV transformer is NG?

Can’t get to the Diode to test without removing unit from wall.

Any light shed would be appreciated.

Thanks,

Al