Another thought...A 6 year old cheapo microwave? In a rig we use to have, I replaced the entire microwave for about $70...found one on Amazon that would fit. Removed the trim, removed the old unit, plugged in the new one, replaced the trim...done.
Older, inexpensive appliance are not worth fixing.
But, glad you were able to find the parts and are happy with the outcome.
"If we couldn't laugh we would all go insane."
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