Advantium 120 problem

Unplug it from the wall for 5 minutes, If that does not cure the issue, you may have a bad or stuck button on the keypad or the main control board is bad.

http://geasupport.custhelp.com/app/answers/detail/a_id/16301/~/advantium-120-volt-error%2C-fault-or-function-codes


Advantium 120 Volt Error Fault or Function Codes

I surmise there's a short in the Quick Defrost button on the keypad. Either the keypad has collapsed there, or some contamination has gotten in. Another possibility is a failing program memory bit in the controller chip, but a contaminated keypad seems most likely. What happens if you press and hold that button while trying to key in another instruction? Is there any change in behavior?

Considering the possibility that replacement of the switches & thermostat may not solve the problem, I would likely look into replacement. Unfortunately, microwave repair parts are expensive and non-returnable.
http://www.repairfaq.org/sam/micfaq.htm has a section on this decision.
Also, broken units still have some resale value.

You have a bad cavity switch. I would guess it is the one behind the vent cover, toward the left side of unit. You would need to remove unit from wall. Remove outer housing to expose cavity switch. You can see it from vent cover, I would test all cavity switches before removing from wall. You should have a diagram of unit folded up behind vent cover towards right side of unit. This tells all workings of unit. Will also tell where all cavity switches are.

Try pushing the clear/off button for 3 seconds to lock or unlock the controls.

I've found the best way to get grease to loosen up in any oven is to place a glass or coffee cup of undiluted ammonia in the oven overnight. The ammonia vapors attack the grease, softening it. The next day:

1. remove the ammonia
2. mix it with a 2 cups of water
3. wear protective gloves
4. using a non-abrasive cloth or sponge wipe the grease off the surfaces.
5. switch to clean water only, wipe the oven one last time to remove the ammonia residue left by the cleaning.

Try unplugging the unit for 30 seconds then plug it back in. The power outage may have been erratic and the MW did not reset properly.

http://www.instructables.com/id/GE-Advantium-Microwave-Halogen-Lightbulb-Replaceme/

How long does it run before it fails? Does it look like the display is getting scrambled characters? I'm leaning toward a bad magnetron, but it may be more or less than that. If you can give more details and especially the actual full model number (as opposed to the model name Advantium 120) that would help. Thanks!