The microwave quit working. No panel lights; no

Make sure that the program controller is working if not check power - step down supply, the pads are responding- if not faulty pads- or the door switches, if the switch contact are not good then it will not trigger the processor to switch on the waveguides. If the lights or fan work without any display or action of program being triggered to start then it can be a possible fault on the main board or the processor. Sometimes insect secretion can short the board and display panel and so the processor can work in such an erratic manner. If so clean, solder and reset the board. Now identify the parts by clicking this link: http://www.espares.co.uk/advice/microwave/a/5/141/identifying-microwave-parts.html

If there is no heating please do not switch on unless you have confirmed the fault. It is possible that the Magnetron is faulty, the temperature cut off is faulty or the main capacitor is short. It is also quite possible that insect can get into the oven and create soft spots. When you switch on these will create a short and make the voltage jump and in the long run damage the magnetron. Check this link to know how a microwave works:

http://www.espares.co.uk/advice/microwave/a/5/1443/how-a-microwave-oven-works.html

see the diagram and pictorial and proceed with common sense:
1) test the fuse for open or band contact with VOM,see the diagram attached how to do it
2)check the switch door hook or door release button,when they are broken they do not touch the switch, and will NOT start. test for open
see the diagram

Unplug the microwave oven for 10 minutes in a attempt to reset the microprocessor ic, press and hold the start button for the same time and release. Now plug everything back in hopes it will restart, if no change! the keypad control board will need to be replaced along with other unknown parts, due to the nature of damage far cheaper to replace.

If "control panel not working" means no display, clock not on, etc. but the interior light comes on when the door is opened(power is being received and transmitted from transformer\rectifier) I would check to see if power is being received by control panel(with a multimeter, checking for voltage at the input terminals). If it is receiving power but not working, the "repair clinic" on the internet is a great place to look for replacement parts.

does the microwave work at all now? Check your power into it, circuit breaker etc

There should be a panel covering the bulb iside the cookspace with a screw holding it on. Remove screw, cover then bulb.

try to unplug and plug back in

We see this a lot. The problem is on the control panel, which we regularly repair nationwide for $39.95 postpaid.

This light failure often occurs when a bulb goes out and the filament shorts, or when the bulbs are removed or installed without first unplugging the oven from the power line. Either can cause such a failure on the controller.

This can often also affect the exhaust fan operation, too. The lights and fan can be inoperable or stuck on too.

Details of our service and critical safety information and disassembly information is at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk

We're happy to help and we appreciate your thoughtful rating of our answer.