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Power transistor identification

Discussion in 'Datasheets, Manuals and Component Identification' started by dsgohio, Mar 21, 2021.

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  1. dsgohio

    dsgohio

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    0
    Mar 21, 2021
    I have a one man hobby machine shop. I bought a Sowon 3Kw induction heater used to heat up shrink fit tool holders. Bought it used - it does not work. Can't afford a new one. Unit blows 15 amp fuses when trying to heat the tool holder.

    I am pretty good at building and fixing my own electronic gizmos - not so good at fixing other peoples circuits. Took the unit apart, removed the circuit board. Everything is on one board that is mounted to a large heat sink. There is no visible damage. First I checked the bridge rectifier - it is good. Next I did resistance checks on the 2 power transistors. I got: 0/0 ohms and 2.2/2.2 ohms and 2.2/2.2 ohms. I'm thinking 0 ohms is not good unless there is a transformer in parallel somewhere. I have not the traces yet. Sadly, the numbers on the transistors as well as the numbers on 4 ic's are ground off. I have no clue how to identify the transistors or the ic's. Any ideas??

    I can only add a closeup picture of the transistors. No matter how I try adding a picture of the whole board always gives me an error...

    Thanks, David 5.jpg
     
  2. dsgohio

    dsgohio

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    Mar 21, 2021
    resized the board picture...
     

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  3. bertus

    bertus Moderator

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    Nov 8, 2019
    Hello,

    It could well be that the manufacturer obscurified the parts, so they must carry out the repair and can charge you for the repair.
    We can not tell you anything without knowing the numbers.

    Bertus
     
  4. dsgohio

    dsgohio

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    Mar 21, 2021
    I have searched the best I could for any info on "Sowon induction heater" No luck finding anything so far.
     
  5. Bluejets

    Bluejets

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    Oct 5, 2014
    I would expect a damaged device such as this to show some sign.

    Removal will be the only option BUT you may do more damage to the pcb than you expect in getting them out.
     
  6. WHONOES

    WHONOES

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    May 20, 2017
    The best way to get those transistors off of the board is to cut the legs close to the transistors then with the aid of a pair of tweezers and a very hot solder iron, the legs can be removed without causing any / much damage. If you don't have a good solder sucker or solder wick then the holes may be cleared using a twist drill that is smaller than the holes. DO NOT try this with the drill bit in an electric drill of any description. Ideally, use a pin vice and rotate the drill by hand.
    It may also help to re - solder the joints after cutting the legs and before removal. Also, if you can adjust the temperature of your solder iron, set it to 390 - 400deg C.
     
  7. dsgohio

    dsgohio

    6
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    Mar 21, 2021
    A quick update. I removed the power MOS transistors. I have a vacuum de-solder station. It works GREAT! Did some research on how to build a induction heater. Found one that uses the FDH44N50 N channel power MOS transistor. The transistor "looks" identical to mine and has specs that seem reasonable. Tested the transistors - one is bad for sure - the other might be bad (gate does not seem to function) the other is shorted - this would blow the fuse. Ordered new transistors. Waiting for delivery. "Might" fix the litter bugger...
     
  8. dsgohio

    dsgohio

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    Mar 21, 2021
     
  9. dsgohio

    dsgohio

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    Mar 21, 2021
    Thanks for the input. I used my vacuum de-solder station. It worked great...
     
  10. Martaine2005

    Martaine2005

    3,596
    979
    May 12, 2015
    Those vacuum solder suckers are great.
    I had to practice for a while as I pulled a few solder pads at first.

    Martin
     
  11. Bluejets

    Bluejets

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    Oct 5, 2014
    Best way to identify many unknowns is to get yourself a component tester.
    Worth around AU$25 on Ebay or similar.
    Possible to compare with known good component and also verify faulty part.
     

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  12. WHONOES

    WHONOES

    1,181
    319
    May 20, 2017
    Have tried them all over the last 50 years or so. Never liked the hot vacuum sucker as it could cause a lot of damage very quickly, nor the hot air devices for use with SMD parts.
     
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