Counted from our technicians' notes on 35 Frigidaire microwave service calls.
Light's on, plate spins, food stays cold
That combination means the heating side has failed while everything else still runs. Microwave heat comes from a high-voltage circuit made up of the magnetron, transformer, diode and capacitor, and if any one of them fails, heating stops. A door switch that doesn't confirm the door is closed will block heating as well.
Timer counts down but nothing happens
The same goes for a microwave that won't start at all. On Frigidaire models, a door interlock switch is a frequent cause. Those switches cut power the moment the door opens, and daily use wears them out. A switch that fails can also blow the main fuse and leave the unit completely dead.
Turntable not turning? Make sure the glass tray and roller ring sit properly on the drive coupling. If they do and the tray still won't move, the turntable motor has probably failed. Keys that don't respond are a different problem. Rule out control lock first, and after that a worn keypad membrane or control board fault is likely.
Stay out of the cabinet
Pulling the plug doesn't make a microwave safe to open. Its high-voltage capacitor keeps enough stored energy to cause a serious shock. Leave the outer cabinet on, and never bypass a fuse or door switch. Stop using it the moment it trips the breaker, hums loudly, smells burned or throws sparks, and pull the plug only when you can reach it without risk.
Four easy checks
- Check the breaker. Over-the-range models are normally on their own circuit.
- Make sure control lock is off.
- Open the door and close it firmly, because a misaligned door can keep the switches from engaging.
- Reseat the turntable tray and roller ring.
The model number is on the interior side trim or the left side panel of the opening, visible with the door open.
Over-the-range models need filter care
An over-the-range Frigidaire microwave doubles as the range hood. Wash the metal grease filters regularly and replace any that get bent. When the microwave recirculates air instead of venting outdoors, change the charcoal odor filter about every six months.
Is the repair worth the money?
Door switches, fuses and turntable motors are modest repairs. A magnetron or control board costs more. On a countertop unit that's a closer call, but on a built-in or over-the-range model it still makes sense in a lot of cases, since replacing one also means removal and reinstallation.