[kjrham]

It seems to work but doesn't heat. I discharged the capacitor and tested it with an ohm meter from terminal to terminal & from terminal to case, infinite resistance. I would test the capacitor on my Knight capacitor tester but it seems to be an electrolytic capacitor since the ohm meter moves momentarily when the terminals are touched but it isn't marked positive & negative. It is a .92uf cap. with an internal resistor. What should I check next?

[PS Staff - Sheila]

It is likely the magnetron that has failed.

Here is a link to your microwave model RM778PXT5.