The convection part works fine. The microwave has never had much power. Can't microwave popcorn. It would seem that porcelain metal tray in there would suck up all the power. I tried it without the tray and no difference. Wonder if the magnetron tube (or is it a klystron) is weak and should be replaced? Any help would be appreciated. This unit is in our RV and would be expensive to replace. We have no other oven so need the convection heat. Thanks for any help Jack