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17PW15-8 blows fuses after lightning

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    17PW15-8 blows fuses after lightning

    Hello,
    I picked this PSU 17PW15-8 from a friend's TV with a burnt fuse, after some days of rain and lightning strikes. The TV was on standby when it happened.
    With new fuses it burns them as well. I checked bridge rectifier, all the TO220 components, diodes and basic caps, replaced IC806 SMPS, and FETS driving the big transformer. I also isolated the secondary circuit by cutting the rails of the FETs to the primary coils. I don't know even know if that makes sense, but I did in hopes to isolate the problem.
    Any ideas what to look for?
    Attached Files
    Last edited by Sraros; 12-04-2023, 01:41 AM.

    #2
    You can try removing the bridge rectifier to see if the problem is before or after it. If it blows a fuse with it out, then you know the problem is before bridge rectifier.
    If it turns out to be before the bridge rectifier, I suggest checking R801 and the class X and Y caps in the filter section.
    Do you have the schematic?
    Last edited by SdlewisSr; 12-04-2023, 08:26 PM.

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      #3
      Hi, The IC806 IC is driving the standby supply, you should also check IC807 driving the other supplies MOSFET Q313 and Q314 that may be shorting

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        #4
        Schematic is at

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          #5
          I have never found IC806 to be a failure and don't know why you replaced that? Anyway look at the circled components and check they haven't shorted as these mosfets can fail on this psu.
          Attached Files

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            #6
            Sorry guys, I rushed a little bit too fast. It was the bridge rectifier afterall... I missed checking between + and 2nd leg. So problem solved.
            Still thanks for the answers

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