Whirlpool WMH76719CS Over Range Micro/Convection RUMBLING

I have a whirlpool micro/convection combo, the range hood and the convection seem to work fine, the microwave rumbles and goes off (occassionally it works, like 1 of 10 tries), I tried replacing the magnetron, I saw one of the blades or fins was broken loose so I thought that was the issue, but I replaced it and it still does the same thing, any ideas?