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Microwave ovens thermal fuse/link/tco

Discussion in 'Electronic Repair' started by Sidney, Sep 28, 2004.

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  1. Sidney

    Sidney Guest

    Rival microwave oven model:MT660,year:Sept 16,2003,UL:52LB,made in
    China.No power I found an open thermal fuse/link/TCO (thermal cut off)
    microtemp # G4A00192C (192 degrees Celcius) physically mounted on the
    side of the magnetron but electrically connected right at the ac line
    cord.Before I replace it I would like to know if it blew by customer
    cooking something too hot or is there a part which caused it to
    fail,as I took my Fluke series II DMM model:29 and measured most
    components on low ohms range and they tested fine.
    Note:the reason why I ask is because long time ago I stopped repairing
    microwave oves as 70% of the ones that used to enter my shop had
    defective magnetrons and the symptoms were no heating of food or
    visible sparks and arcs.
    Oh yeahm,this model has a bake and broil element like a regular
    kitchen stove and it also has a turntable motor on the bottom.Thanks
    in advance for tips.

    Dartmouth,Nova Scotia
  2. You may have to just replace it (or bypass it if only testing) to see if
    anything else is actually bad. It was there to detect overheating of the
    magnetron. There can be many causes of that, or it may have just died
    for no good reason.

    Take care in there!

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  3. James Sweet

    James Sweet Guest

    Not sure about this particular unit, but I've yet to come across a bad
    magnetron, usually the fuse is blown from a sticky interlock switch on the
    door, or there's cracked solder joints on the control board. Not to say
    magnetrons never fail, but there's plenty of other more common problems it

    If you have one of those IR thermometers you could put some water in the
    unit, bypass the thermal fuse with a clip lead and run it for several
    minutes while checking the temperature of the magnetron periodically, if it
    doesn't get too high after 10 minutes of running then it's probably ok and
    you could put a new thermal fuse in.
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