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Please help me recognize clamp-meter's cap ratings for replacement

Discussion in 'Repairing Electronics' started by BGAmodz, Sep 18, 2013.

  1. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    On this page, there is datasheet for a microwave triac. In the datsaheet there is a simplified schematic of a microwave transformer. http://www.datasheetcatalog.com/datasheets_pdf/A/N/4/4/AN441.shtml

    Here, http://www.appliancessolution.com/products-2 is a interesting page because it has real specifications of the parts such as the magnetron and capacitor.

    Trying to measure the secondary will likely result in meter damage. One will be about 3 VAC and the other basiccally not measurable.

    If you look at the magnetron pictures , you will see 3 connections: 2 for the filament and one for the high voltage. Then a 4th connection would be ground.
     
    Last edited: Sep 24, 2013
  2. BGAmodz

    BGAmodz Member

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    I think you guys are more experienced than me and you are totally right , i will get away from microwaves for my own safety .

    After a little searh about this HV transformer , i see that secondary is both stepped up and stepped down , but how can measurement be performed on that side ? (am not gonna try that just for knowledge)
     
  3. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    debe
    Very nice manual.

    Can you do me a favor and look for a schematic for a Mid 80's Vintage Sanyo/Kenmore Micro Convection control board p/n 12360 The Sears model # is: 564.8668410, Sanyo Model is EM-5525. The control board part number is: 12360. A 12360 control board would also interest me.

    I'd appreciate it.
     
  4. dave

    Dave New Member

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  5. BGAmodz

    BGAmodz Member

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    Really interesting diagrams , i got a clear idea now . and i do realize now how dangerous the stuff i was messing with .
     
  6. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    There are a few possibe ways of transformer testing:
    1. Ringing - See http://www.google.com/url?sa=t&rct=...g-wjoI1oqXyzAxadLzakQ_Q&bvm=bv.53077864,d.dmg

    This is really the safest method.

    Now you could possibly use a HV probe. e.g. http://www.grainger.com/Grainger/FL...1T321&ef_id=UkIu6gAAAH8zqRkQ:20130925003138:s

    In cases using a HV probe, all connections need to be made with the device unpowered and you ALWAYS have to use the "One hand in pocket" rule.

    Those are the two safest methods,

    Under VERY CONTROLLED conditions, I might be TEMPTED to use a second transformer connected secondary to secondary (high voltage side) with both a fuse and "light bulb" current limiter. A tungsten bulb in series with the primary would act as a current dependent resistor. then you would be measuring the resultant 240 VAC developed.
    240:2400 and 2400:240 and a battery powered meter and no hands.

    High voltage and sharp points do not get along, The HV arcs to and from sharp edges.

    A GFCI protected outlet MIGHT help.
     
  7. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Jesus!! - are you serious?.

    You've already done one utterly stupid and suicidal thing, and you're carrying on doing the same stupid things.

    Please - DON'T have anything to do with microwave ovens, you're not safe to be near one.

    You've also quite possibly killed your new meter?, unless you were lucky enough to accidentally connect it wrongly
     
  8. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You don't, there's no need to - a microwave oven is a VERY, VERY simple device - you just need a meter that will read about 5000V DC, which is negative with regard to chassis.

    I actually use an old Avo meter which has a 3000V DC range, which reads off scale initially, but drops back to just below 3000V as the mag fires up.

    But again, if you have to ask - DON'T TOUCH ONE.
     

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