My buddy, a pro carpenter among other things, got me a used GE Profile
over-stove mounted microwave/convection oven. Took us an hour and a half
to remove old one and install the GE. Guess what. Didn't work!

He thought it did, as the panel lit up, turntable turned, etc.
But!.... damned if the magnatron wasn't shorting out to the revolving
turntable post. BIG BLUE arcs! And, it was almost brand new! Whatta
waste.

So, we gotta un-install it and take it back to the RE-Store (Habitat
fer Humanity 2nd hand store) fer a different one. Bottom line:
thoroughly check the unit before purchasing it!!!

nb