A microwave with a lit display and no heat has two separate possibilities: it is not starting, or it starts and does not heat. Decide which one you have, because they have different causes.
It will not start
- Close the door firmly. The door switches must all register a closed door.
- Check for a control lock setting and release it.
- Press Cancel, then try a simple 30-second run.
- Unplug for a minute and plug it back in to reset the display.
A microwave that does not start after those steps may have a door latch switch that has worn out, or a blown fuse behind the control panel. Both can be confirmed with a meter.
It starts but food stays cold
Put a cup of water in the unit for one minute. If the light, fan and turntable run but the water stays cool, the heating parts are not working. Those include the magnetron, the high-voltage diode and the capacitor. The high-voltage section holds a charge even when the microwave is unplugged, so this is not a job to open up at home.
Over-the-range models
If your microwave is mounted above the range, check the outlet and any breaker or GFCI that feeds it. Steam and grease can also affect the touch panel, and wiping the panel with a damp cloth sometimes restores response.
The limit of home checks
Sparks, a burning smell, a cracked door or a door that sits crooked in its frame are reasons to stop using the microwave. The cold-water test can tell us the heating section is out, but it cannot say which part, so we test it at the unit.
A microwave that stays cold or silent after the checks should be tested with a meter, and the high-voltage parts are ours to handle. Reach us through the microwave repair page; we serve the Houston area, quote in writing and guarantee our workmanship for 30 days.