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    SMPS Switching transistor getting too hot

    hi
    I am trying to repair a SF-PW yamabishi make CNC sprintle control power supply.
    Now the smps on but,switching transistor C3150 getting too hot.The older transistor was C3148.
    I put C3150 instead of C3148. the datasheets are almost same .
    anyone have experience about this power supply please help.

    regards
    Maxim

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    Re: SMPS Switching transistor getting too hot

    That schematic doesn't show a functional power supply circuit. Show the whole thing.



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    Re: SMPS Switching transistor getting too hot

    Quote Originally Posted by mtwieg View Post
    That schematic doesn't show a functional power supply circuit. Show the whole thing.
    Sorry,I don't have a full schematic



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    Re: SMPS Switching transistor getting too hot

    By itself that circuit does absolutely nothing, and therefore can't heat up. Can't help you if that's all you can show.



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    Re: SMPS Switching transistor getting too hot

    Power supply repair is usually electrolytic capacitor replacement.
    Or maybe MOV and fuse replacement if it got taken out by a transient.
    Or maybe NTC replacement.
    Or fan replacement
    Or optocoupler replacement.
    Possibly power fet replacement if it was in severe temperature variations (bond wires snapping due to severe expansion & contraction)



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