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Replace fried range hood transformer with cheaper alternative?

Discussion in 'General Electronics Discussion' started by samaja, Apr 6, 2016.

  1. samaja

    samaja

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    Apr 6, 2016
    Transformer on range hood died, so that the two 12 V halogens quit working. Fan unaffected, still works. My question is whether I can replace this original:
    [​IMG]

    with this much less expensive transformer, also from a range hood, different brand:

    [​IMG]

    If not, why not? I ask here, rather than on an appliance repair site, because I trust that here I can get a real satisfactory, explanatory electronicsy answer, rather than a perfunctory, "No, is difrent. Want burn down hoose? lolz."

    hope the pics provide needed info. FWIW, the lights on the range hood do not dim. Simple on and off switch.

    And let's say this is hypothetical.

    Thanks for any response.
     
  2. BobK

    BobK

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    Jan 5, 2010
    If I read it correctly (it is a bit fuzzy) I see the original is 12V 60W which is 5A and the replacement you want to use is 4A. So, no you need a slightly higher power one.

    Bob
     
  3. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    .


    Sir samaja. . . . . . .

    Question . . . .?
    I see that you opened that unit enough to expose the end Euro connectors.
    Is it also possible to expose and see the circuit board and its mounted components?
    Or is it potted up ?

    With this being a switch mode power supply design . . .and assurredly being very near heated
    environs . . .it is very likely that the units electrolytic caps have gradually faulted and let the unit
    slowly taper down to a state of inoperativeness.
    Is a fuse visible and is it still good ?
    This unit just might be revivable .


    73's de Edd


    .
     
  4. Bluejets

    Bluejets

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    Oct 5, 2014
    In addition to Bob's answer above, you could use the replacement if you also replaced the lamps with 2 x 20W.
     
  5. duke37

    duke37

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    Jan 9, 2011
    The original has thermal and short circuit protection. Do you want to lose these facilities?
    Try repair if you can get inside.
     
  6. samaja

    samaja

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    Apr 6, 2016
    Thanks, guys. I guess this isn't a viable replacement. The original (no continuity) shows signs of heat on the backside of what I understand is the transformer. I think I'm going to go ahead and order the pricey replacement. But here's pics of the original's internals:

    2016-04-07 19.14.44.jpg 2016-04-07 19.15.02.jpg
     
  7. Bluejets

    Bluejets

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    Oct 5, 2014
  8. 73's de Edd

    73's de Edd

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    Aug 21, 2015

    Sir Samaja . . . . . . .


    Those photos should have been taken outdoors . . . . in subdued sunlight.

    However . . . . . with my applying a little "NASSER" pixel dithering and time averaging enhancement, I can still come up with:

    [​IMG]

    NOW I can see that the unit applies its created Hi Freq AC directly, as its output to the lamps.

    Also you have a round, reddish brown special fuse as the F1 in the primary circuit of the unit, . . . see RED CIRCLE markup . . . .about 1 inch up from its AC power input terminals.

    Is it good ?

    If it is good, then possibly you have merely experienced a "soft failure" . . . with a time/use related warming up of the two YELLOW circled electrolytic capacitors and their slow degradation of their capacitance on down to a gradual non operational state / threshold.

    Its worth a mere couple of bux . .to confirm that . . . . with their replacement . . . .use 105 deg C temp rated units for longevity..

    73's de Edd


    .
     
  9. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    And folks wonder why an appliance repair service has to charge upwards of $70 per hour to find and replace a $10 piece of imported junk... electrolytic capacitors mounted over a range hood? They should have used 117 V halogen lamps.
     
  10. ChosunOne

    ChosunOne

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    Jun 20, 2010
    Okay, there's something I don't understand here. The "transformer", which is repeatedly being referred to as a transformer, is obviously an assembly of components built around the actual transformer. This appears to be one of those jargony things where an entire assembly of components is called by the central element.

    I've worked decades in an industry that uses transformers that are actually just transformers--even though most of them have a fuse inside the housing, but those that don't are still transformers. So I'm curious here: I know that an incandescent light source can work on whatever voltage it's designed for, and a 12VAC step-down transformer in the USA will deliver a nominal 12VAC (actually closer to 14VAC OCV in most instances), but it's the voltage that the bulb is designed for.

    What is all the extra circuitry for?
     
  11. hevans1944

    hevans1944 Hop - AC8NS

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    Looks like some of these "electronic transformers" are designed to also serve as dimmers. I guess the range hood manufacturer wanted to try to cover as many bases as possible.
     
  12. Bluejets

    Bluejets

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    Oct 5, 2014
    Basic switchmode supply. Designed to keep the size of the transformer small by changing the frequency usually. Input rectified then changed to different frequency then stepped down.
     
    hevans1944 likes this.
  13. BobK

    BobK

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    Yes, a 12V 5A transformer would be large and heavy.

    Bob
     
  14. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    .



    “I believe the appropriate metaphor here involves a river of excrement and a Native American water vessel without any means of propulsion.” ― Sheldon Cooper

    following the same thought train . . . and semantics . . . . .as being applied to an electronic transformer

    “ My heavens . . . . . . . . that little thing is as light as a popcorn fart." . . . . . . . bazinga !









    .
     
  15. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    Whereas this fine stainless steel oven hood requires two men and a boy to hoist it into place and secure it. So let's save some weight here...
     
  16. Bluejets

    Bluejets

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    Oct 5, 2014
    I'm guessing they are trying to be safety conscious using low voltage to the MR16 type lamps in preference to the high voltage GU10 style.
     
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