Power level setting doesn't seem to change how food cooks

Symptoms

• Food seems to cook the same regardless of selected power level
• Timer and other functions work normally
• May be more noticeable on delicate foods like melting chocolate or cooking eggs
• Full power (100%) works as expected

Likely causes

• CommonUser setting errorSome models require pressing a specific power-level button before entering time, and skipping this defaults to full power.
• PossibleFailing inverter board (on inverter-style microwaves)As covered in the inverter guide, this board specifically manages lower power output.
• PossibleRelay or control board issue (on standard cycling-style microwaves)Standard microwaves achieve lower power by cycling the magnetron on and off, and a relay fault can prevent this cycling.

What to do

1. Re-check your manual for the exact steps to set a power level, since order of button presses varies by brand.
2. Test a clearly lower level, like 30%, with a food that shows a difference easily, such as melting a small piece of chocolate or butter.
3. Listen closely during a lower-power cycle on a standard (non-inverter) microwave; you should hear the magnetron cycling on and off rather than running continuously like on full power.
4. If you don't hear any cycling and food cooks as if at full power regardless of setting, this points to a relay or control board issue.
5. For inverter models, refer to the inverter-specific guide for testing steps.
6. Have a technician test the specific relay, inverter board, or control board once you've confirmed correct usage.

Tools and parts

When to call a pro

If correct usage is confirmed but power levels don't actually change output, have a technician test the relay, inverter board, or control board.

Safety