F20559Y00AP Genuine Wave Guide Mica Cover for Panasonic Microwaves NN-SD691S NN-ST641W NN-ST651W NN-ST663W NN-ST665B NN-ST671S NN-ST683S

A burnt or sparking patch on the inside wall of a Panasonic microwave usually means the waveguide cover needs replacing. F20559Y00AP is the genuine Panasonic mica cover for the NN-SD691S and NN-GD682S, and for NN-ST models including the NN-ST641W and NN-ST64JW, the NN-ST651W and NN-ST655W, the NN-ST663W and NN-ST665B, and the NN-ST671S, NN-ST67JS and NN-ST683S.

Panasonic microwave sparking inside?

Microwaves travel from the magnetron down a short channel called the waveguide and into the cooking cavity. The mica cover sits over the opening in the cavity wall, letting the energy through while keeping food splatter and steam out of the waveguide. Over time, grease and food soak into the cover and carbonise, and the burnt spot can arc, spark and crackle during cooking. Left alone, arcing can damage the waveguide and the magnetron, so stop using the microwave and fit a new cover once you see burning or sparks.

Part details

• Genuine Panasonic part F20559Y00AP
• Mica waveguide cover
• Listed for NN-SD691S and NN-GD682S plus NN-ST series models

Changing the mica cover

Unplug the microwave before starting. The cover is on the inside wall of the cavity and is normally held by clips or tabs, so it can be changed without opening the outer case. Never remove the outer case yourself, as microwaves store dangerous high voltage even when unplugged. Clean any grease or carbon from around the opening, fit the new cover the same way round and test with a cup of water.

Questions about this part

Can I cut a sheet of mica to fit instead?

Mica sheet can be cut, but this genuine cover is already shaped with the right fixing points for these Panasonic models, so it fits without trimming and sits flush. A poorly fitted cover can leave gaps that let splatter into the waveguide.