Microwave sparks

A two year old Panasonic over the range microwave sparks after steam enters the exhaust chamber. No stream no spark.

This is a view from the bottom of the microwave. It is shot through the air intake at the bottom of the microwave. The white box shown contains a high voltage circuit board running at 3kV (the 'Inverter' board). As usual, this over the range microwave doubles as a cooking exhaust fan. I suppose this circuit board surface electrically breaks down on high voltage after 2 years of grease accumulation from cooking oil vapor. Stream condense to water on the board which further helps the electrical break down causing the sparks as shown in the video.
The microwave works as normal after a few sparks.

After disassembly, the circuit board was found to have a dark trace of burnt material and some grease in the same position where the spark is observed. The circuit board was replaced and problem was fixed. I believe this is a general design problem for all Panasonic OTR microwaves.

Category:

Science & Technology

Tags:

• Panasonic
• microwave
• spark
• high
• voltage
• breakdown
• lightning
• DIY
• electronics
• kitchen

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Good thing you got it fixed.