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Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

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    Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

    Hello everyone! I own the TV as per subject that out of the blue with no apparent cause (I mean storms, black-outs and the like, obviously there was a cause!) went off. Immediately before I've literally heard an explosion (then, after opening it, I've understood why!).
    It was the C9107 capacitor literally exploded with a flame that had blackened the whole surrounding area. I also checked the input fuse, also gone.
    I replaced both components and, as I feared, just after reconnecting power I've got exactly the same result. Both components went the exact same way. To tell the truth (but I have to physically check the board which I don't have at hand now) looking better at the photo now it seems to me that the adjacent button capacitor C9103 is also damaged while the first time it wasn't so.
    The power supply is a 715g7364-p02-001-002M. I attach detailed photos and service manuals of both the TV and the power supply (the power supply one is for the 715g7364-p01-001-0020 but everything matches).
    Could you give me a tip? The replacement board seems impossible to scour... Above all, given the massive damage is it worth looking for a replacement or attempting a repair or is it likely that the motherboard and / or the screen have also been damaged? Thanks everyone and have a nice day!
    Attached Files

    #2
    Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

    Are you sure it was that capacitor that went faulty. It tends to be the snubber capacitor (C9103) for the mosfet (Q9101) that tend to go faulty in the manner you describe.
    Check C9103, Q9101, R9101 & D9101
    Last edited by dick_barton; 01-31-2021, 11:50 AM.
    Willing to help but I'm no expert.

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      #3
      Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

      You can see (in the picture) that C9103 is damaged and likely shorted. It will be rated at 1kv replace it with a 2kv
      Last edited by R_J; 01-31-2021, 11:59 AM.

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        #4
        Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

        Originally posted by dick_barton View Post
        Are you sure it was that capacitor that went faulty. It tends to be the snubber capacitor (C9103) for the mosfet (Q9101) that tend to go faulty in the manner you describe.
        Check C9103, Q9101, R9101 & D9101
        Hi and thanks for your help as always. We've already 'met' and you've always been very kind and free to help! I can confirm that even C9103 is gone (it wasn't so the first time, at least apparently). I attach a detailed photo.
        What's certainly damaged are the fuse, C9103 and C9107 (the right naming for the previously attached photo is ali_c9107 and not ali_c9103 as I've mistakenly written). I would test Q9101, R9101 and D9101 (what about D9103?). I assume all of them need to be desoldered, don't they? Could I make the check in circuit just to see if the diodes are shorted? I don't know but for R9101 and Q9101 I'm rather certain I need to desolder them, the main problem being Q9101: I haven't ever desoldered a mosftet and apart from the screw I imagine it is bonded to the heatsink with thermal glue; I could try with a cutter but I fear to damage the packaging...

        Originally posted by R_J View Post
        You can see (in the picture) that C9103 is damaged and likely shorted. It will be rated at 1kv replace it with a 2kv
        Thanks for your help and the advice about the rating. I would take it into account. As I was previously explaining, you're right: I can confirm even C9103 is gone.

        A nice day to the both of you!
        Attached Files
        Last edited by guybrushthreepwood; 02-01-2021, 04:40 AM.

        Comment


          #5
          Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

          Hello again. I've checked on the service manual and both D9103 and D9101 are FR107G-A0 rectifying diodes 1kV 1A. Is a 1N4700 a suitable replacement? It should according to the specs if I'm not missing anything...
          C9103 is a 1kV 100pF and, as adviced, I would replace it with a 2kV 100pF.
          For what concerns R9101, on the service manual I read only 0.2R: shouldn't I have also a Wattage and percentage? What does 0.2R mean anyway? I apologize for the dumb question but I've made a search and I couldn't find an answer.
          Finally, Q9101: a N channel 18A 650V 50W to-220f transistor (AOTF18N65).
          As already asked: is there a quick way to check them in circuit or do I have to desolder everything? Thanks again.
          Last edited by guybrushthreepwood; 02-01-2021, 10:40 AM.

          Comment


            #6
            Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

            I've checked on the service manual and both D9103 and D9101 are FR107G-A0 rectifying diodes 1kV 1A. Is a 1N4700 a suitable replacement? It should according to the specs if I'm not missing anything...
            The 1N4007 is not suitable as the FR diodes are fast recovery diodes intended for high frequeny rectifying.


            C9103 is a 1kV 100pF and, as adviced, I would replace it with a 2kV 100pF.
            That should be a suitable replacement.

            For what concerns R9101, on the service manual I read only 0.2R: shouldn't I have also a Wattage and percentage? What does 0.2R mean anyway?
            The 0.2R means the reistor is a 0.2 ohm resistor. Not sure of the wattage. Attach a picture of it.


            Finally, Q9101: a N channel 18A 650V 50W to-220f transistor (AOTF18N65).
            As already asked: is there a quick way to check them in circuit or do I have to desolder everything? Thanks again.

            Initially you can use your multimeter set to diode mode and check between the three legs to see if there is a short circuit between any of the 3 legs. If there is a low reading but you're unsure then you could remove the mosfet and test out of circuit. Plenty of Youtube videos showing how.
            Last edited by dick_barton; 02-01-2021, 05:34 PM.
            Willing to help but I'm no expert.

            Comment


              #7
              Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

              Originally posted by dick_barton View Post
              The 1N4007 is not suitable as the FR diodes are fast recovery diodes intended for high frequeny rectifying.
              I was certain I was missing something! Too good to be true... The fact is that I could easily scour 1N4007s while I've found the exact replacement only from stores which don't accept orders from me because of volume and/or me not being VAT registered. I don't know what to do apart from hoping they're fine as it wouldn't probably be.

              Originally posted by dick_barton View Post
              The 0.2R means the reistor is a 0.2 ohm resistor. Not sure of the wattage. Attach a picture of it.
              The picture is attached. Please tell me if its quality isn't good enough.

              Originally posted by dick_barton View Post
              Initially you can use your multimeter set to diode mode and check between the three legs to see if there is a short circuit between any of the 3 legs. If there is a low reading but you're unsure then you could remove the mosfet and test out of circuit. Plenty of Youtube videos showing how.
              Thanks for everything!

              EDIT: I've searched for a suitable replacement adding the new information given by Dick and I've found MUR1100ERLGs which are still rectifying diodes 1kV 1A but ULTRA fast, not just fast. I've also found them where I can buy from. Are they fine? Here the datasheet:

              https://eu.mouser.com/datasheet/2/30..._D-1811932.pdf

              which compared with the one for FR107G-A0:

              http://www.smc-diodes.com/propdf/FR1...42%20REV.A.pdf

              make me think they should be a suitable (also a bit more solid) replacement but, again, I may be missing something relevant like it was before.
              Attached Files
              Last edited by guybrushthreepwood; 02-02-2021, 05:17 AM.

              Comment


                #8
                Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

                The diode replacement after a quick look appear to be a good substitute.

                Look again in Mouser for 0.2 ohm (200 milli ohm) metal oxide axial resistors and compare the size shown on their data sheet to the one on your board which hopefully will match one of their 1 Watt, 3 Watt or 5 Watt versions.
                Last edited by dick_barton; 02-02-2021, 09:17 AM.
                Willing to help but I'm no expert.

                Comment


                  #9
                  Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

                  Just a note on NEW resistor wattage sizes from some manufacturers, I ordered some 4.7Ω 1watt (Yageo brand) from digikey and they were about the size of old 1/4 watt resistors. I checked the datasheet and they were correct wattage for their physical size.
                  I have new replacement resistors rated 1/2 watt but are also older 1/4 watt size.
                  Last edited by R_J; 02-02-2021, 11:26 AM.

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                    #10
                    Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

                    The same issue here: both the snubber capacitor (C9103) and the mosfet (Q9101) were blown up. Replaced the 100 pF C9103 with a 2kV version and replaced Q9101 with an NTPF190N65S3HF. TV is working fine again :-)

                    Comment


                      #11
                      Re: Philips 32PFS6402-12 qm17.4e_la repeating PSU capacitor and fuse blow up

                      Hi! have you found the type of resistor you need for R9101? i'm having the same problem here... any help would be very much appreciated!!!

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