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Microwave runs but won't heat

Discussion in 'Electronic Repair' started by bones, Sep 8, 2005.

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  1. bones

    bones Guest

    I have a "Figidaire Gallery" over the range microwave. I turned it on to
    reheat food and I heard a click. The microwave still ran but it did not
    heat the food.

    At this point, the appliance turns on but it does not kick in to heat
    anything up (tried every option and still the same). Any ideas on what it
    might be?

    Thanks
     
  2. Magnetron! or HV supply.Get an engineer it's probably not an easy fix
    for a non-qualified person[if that's you,if qualified then read Sams
    instructions] If not qualified don't open it.Regards
     
  3. Bob Shuman

    Bob Shuman Guest

    Or an open door safety microswitch...


     
  4. Yes, it could indeed be something simple but microwave ovens ARE the MOST
    DANGEROUS household appliance to work inside.

    If you have no experience with high voltage electronics, leave it to a
    professional. This is for your own safety.

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  5. James Sweet

    James Sweet Guest

    I've fixed a couple that had cracked solder connections at the power relay
    on the control board, could also be a bad diode or capacitor in the HV
    circuit but usually that blows the oven fuse.

    *Read the repair FAQ BEFORE* you think about opening this thing up,
    microwaves are relatively simple to work on but they can be lethal if you
    don't know what you're doing.
     
  6. bones

    bones Guest

    I had to send in the microwave because I didn't really know what I was
    doing. The repair guy tested it with a meter plugged into wall while
    microwave was plugged into it. He said it was drawing 4 amps so he said it
    was probably a diode or capacitor. Since you suggested this does the 4 amp
    senerio sound correct?
     
  7. Possibly but less likely than a bad connection to the magnetron filament..

    HV diodes and capacitors usually fail shorted, which would draw more current.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  8. bones

    bones Guest

    After two weeks in the Sears repair shop, they finally looked at my
    microwave and they told me that I need a new transformer. Going by my
    earlier postings regarding the problems and the replies that I received, do
    you think that this sounds like a good diagnosis? It will cost me $400
    Canadian. I bought the microwave in '99 for $600 Can. If it is an accurate
    diagnosis do you think it would be worth to fix it at this price?

    Thanks
    Jeff
     
  9. sofie

    sofie Guest

    bones:
    6 years later..... facing a $400 repair bill.... it is time to trash it.
    (He's dead, Jim)
    New, full feature Microwave ovens can be purchased for much less than the
    proposed repair bill.... unless you are looking for some peculiar feature
    or size that only is found on the high priced units .
    Keep it simple and you can probably get a new one for a couple hundred
    dollars or so... (Canadian)
     
  10. Although I worked in a shop that repaired them, I never did a repair
    myself, but...isn't a transformer failure a rarity, an oddity?

    Tom
     
  11. But the diagnosis doesn't make sense either if what they mean is the
    high voltage transformer.

    The only likely failure of the HV transformer would result in a very high
    current and probably a blown fuse. This would be due to shorted turns in
    the primary or HV winding.

    The original service guy tested the line current and said it was only drawing
    4 A. That sounds like the input current to an unloaded HV transformer
    4 A is consistent with the (partially saturating - normal) HV
    transformer when not loaded. So, most likely cause is a bad filament
    connection to the magnetron or a bad magnetron. The HV capacitor normally
    fails shorted, as does the HV diode, though if it exploded, it would be
    open. :)

    And, the *ONLY* excuse to charge $400 for a transformer is that they simply
    do not want to fix it! Go on eBay and you can probably pick one up for $10.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  12. Certainly not that common, but see my other posting. I doubt it's the
    transformer.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  13. James Sweet

    James Sweet Guest


    That sounds unlikely, the only time I've *ever* seen a microwave transformer
    fail was on an ancient Amana RadarRange and that was 20 years ago, the oven
    started billowing putrid smoke.
     
  14. James Sweet

    James Sweet Guest


    Well he did say it's the Sears shop, generally those guys are idiots, my
    grandparents had a service contract with them for years, half the time they
    couldn't even fix a dishwasher or clothes dryer on the first trip out, and
    even so all they did was swap parts until the thing worked.
     
  15. bones

    bones Guest

    Thanks to all for the replies. I will question Sears and also let them know
    that I've been told that this is a rarity.
    And I will let you know what they say.

    Jeff
     
  16. James Sweet

    James Sweet Guest


    The morons will probably just look at you like you just landed from outer
    space.
     
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