Panasonic · Microwave error code

F04Line voltage too high for setting

Cross-checked High-voltage / caution

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Related diagnostic guides

Guide · Microwave

Microwave heats slowly or weakly

Confirm with a water test on High. Then rule out a low power setting and low line voltage, since a small voltage drop cuts output a lot. An aging magnetron is the most common part cause; poor connections and a failing thermal protector also show up.

4 steps ~30 minadvanced

Guide · Microwave

Microwave door, interlock and leakage: what the federal standard requires and what to check after a door or switch repair

US microwave ovens are built to the FDA performance standard (21 CFR 1030.10): leakage may not exceed 1 mW/cm² as sold and 5 mW/cm² for the life of the oven, measured about 5 cm (2 in) from the surface, and every oven must have two independent interlocks plus a monitoring system that stops the oven if the interlocks fail. In the field that means a damaged door, hinge or seal is a stop-use condition, every interlock part goes back exactly as designed, and a door or switch repair should end with a leakage survey using a microwave survey meter. This guide covers the checks; it does not cover high-voltage work beyond the standard discharge warning.

5 steps ~30 minadvanced

Guide · Microwave

Replace the over-the-range microwave door interlock switches (discharge the HV capacitor first)

Microwaves have two or three interlock switches (primary, secondary and a monitor) at the door latch. They are high-safety parts: the monitor switch deliberately blows the line fuse if the others fail closed. On over-the-range units access is usually by removing the control panel or vent grille and the latch/switch bracket. Unplug, discharge the high-voltage capacitor, replace all the switches with the exact types for each position, replace the fuse, and test.

10 steps ~60 minadvanced

More Panasonic microwave codes

Panasonic · Microwave

E01

Fault - stop using

Single source High-voltage / caution

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F05

Control memory failure

Cross-checked High-voltage / caution

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F33 / F34

Exhaust temperature sensor open (F33) or shorted (F34)

Single source High-voltage / caution

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F44

Keypad pressed too long / keypad fault

Cross-checked High-voltage / caution

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H95

No microwave oscillation (magnetron/inverter)

Cross-checked High-voltage / caution

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H96

Inverter / high-voltage circuit fault

Cross-checked High-voltage / caution