Need Appliance Repair Help? Ask a Technician for Answers ASAP
F84 is a communication error between the microwave control board and the user interface (front display board). This error is a terrible error to get because all you can really do is pull the unit out, remove the top panel and make sure the wires are secure. if that all checks good then you either have a faulty interface board or a faulty microwave board. There is no way to test which board is faulty so usually the front interface display board is faulty and the one you'd need to order and replace first. Below is a link to the part.
CLICK HERE for user interface board
We are on the honor system here. Please remember to rate my service by selecting a star at the top of the screen before you leave today. If you need anything else, just let me know. You can continue asking follow-up questions at no additional charge after rating my service if you still need assistance.