• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

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Panasonic NN-SN973S Microwave Shuts Off After 7-8 Seconds/Then Powers Back On


Premium Member
Jul 8, 2020
Model Number
1-5 years
My Panasonic NN-SN973S just recently started shutting off after 7-8 seconds of microwaving. The microwave powers off and then, after a second and a clock reset, powers back on. I can repeat this process with the microwave running on full power for 5-8 seconds each time, then powering off, and then back on. If I reduce the power level, say to a 6, then the microwave seems to work fine (but has the same problem as I move up to 7, 8, or 9). Is this likely a thermostat issue? Anything else I should try. I;ve only had the machine for a few years, it is a built-in, and I'm frustrated that I need to potentially replace it so soon,. Any help appreciated! Thanks!
Thanks. I don't doubt you, but could it not be the thermostat? It seems odd that it works fine at lower power. For the cost of the board, even if I can get one, probably better to just buy a new one. Thanks again!
..... but could it not be the thermostat?
No, one of the power relays on the board is causing the problem. There's two types of thermostats or TCO's in that machine. Most are a one shot deal. The only 'thermostat' is a normally open thermostat that turns on the cooling fan at a set temperature. When it cools the fan shuts off. None of the TCO's would affect the display panel.
Thanks so much. I really appreciate the explanation as it makes me feel better about moving on from this unit to something new. You have a great day!
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