Replaced bulging caps, and pop... nothing

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  • Karstedt
    New Member
    • Jan 2011
    • 6

    #1

    Replaced bulging caps, and pop... nothing

    I have one of those va912b's with a bad power supply. I replaced 3 of the caps that were bulging, and when I plugged it pack in, I heard a pop (not an exploding cap) and nothing happened. Did I fry it with a bad joint or something? Or should I just replace the other caps too (except the big one).
  • Karstedt
    New Member
    • Jan 2011
    • 6

    #2
    Re: Replaced bulging caps, and pop... nothing

    Now with pics of my masterless work. I circled the new caps, and the only joint that rally concerns me is the bottom one with the slight scorching around it (that was there before I got to it). I struggled with that joint.
    Attached Files

    Comment

    • Trinite
      Senior Member
      • Dec 2010
      • 143

      #3
      Re: Replaced bulging caps, and pop... nothing

      Show us a picture of the switchers and the diodes. Those are the other things that tend to go "pop". Also a complete pic of the underside of the board would help too, as there are a lot of SMD components on that side.

      Comment

      • retiredcaps
        Badcaps Legend
        • Apr 2010
        • 9271

        #4
        Re: Replaced bulging caps, and pop... nothing

        Originally posted by Karstedt
        I heard a pop (not an exploding cap) and nothing happened.
        Generally, when you see 3 bad caps, you might want to replace them all.

        Did you install one of the caps backwards?
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        Comment

        • Karstedt
          New Member
          • Jan 2011
          • 6

          #5
          Re: Replaced bulging caps, and pop... nothing

          Originally posted by Trinite
          Show us a picture of the switchers and the diodes. Those are the other things that tend to go "pop". Also a complete pic of the underside of the board would help too, as there are a lot of SMD components on that side.
          Well, I can post some different angles and a complete underside. But I can't really get a much closer pic of anything... they get way out of focus.

          Originally posted by retiredcaps
          Did you install one of the caps backwards?
          Definitely not.
          Attached Files

          Comment

          • Ritalin
            Senior Member
            • Sep 2010
            • 194

            #6
            Re: Replaced bulging caps, and pop... nothing

            Ya, I agree with replacing the others as well. Usually when they are in a cluster like that, they all get affected. You could take off the other ones and test them with a meter if you have one. Also check the bottoms of them for bulging, for some reason some brands tend to go bottom first then bulge at the top if it's that bad.

            Comment

            • yyonline
              Badcaps Veteran
              • Jul 2009
              • 692
              • USA

              #7
              Re: Replaced bulging caps, and pop... nothing

              I'd expect that area of a power supply to use low ESR caps. I am not familiar with the "NTE" capacitors you used as replacements. What are their specs and how do they compare to the originals? They're not a brand I've heard of before, so I'm unsure of their long term reliability.

              Comment

              • retiredcaps
                Badcaps Legend
                • Apr 2010
                • 9271

                #8
                Re: Replaced bulging caps, and pop... nothing

                If you have no power and no power LED, then check the bridge rectifier (BD101) for shorts. Number the pins 1-4 and put your multimeter on 200 ohms.

                With power off and lcd unplugged, measure pins 1-2, 1-3, 1-4, 2-3, 2-4, 3-4. Any reading under 30ohms suggests that the bridge rectifier may be shorted.
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                We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

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                Comment

                • Karstedt
                  New Member
                  • Jan 2011
                  • 6

                  #9
                  Re: Replaced bulging caps, and pop... nothing

                  Originally posted by yyonline
                  I am not familiar with the "NTE" capacitors you used as replacements. What are their specs and how do they compare to the originals?
                  They are higher voltage with the same uF as the originals. I don't know the other specs, and haven't used them before either. They were available at the local electronics parts store, and they use them for repairing LCD's...

                  Originally posted by retiredcaps
                  If you have no power and no power LED, then check the bridge rectifier (BD101) for shorts. Number the pins 1-4 and put your multimeter on 200 ohms.

                  With power off and lcd unplugged, measure pins 1-2, 1-3, 1-4, 2-3, 2-4, 3-4. Any reading under 30ohms suggests that the bridge rectifier may be shorted.
                  You are correct, no power, no LED. I'll check that this weekend. Thanks.

                  Comment

                  • mastertheknife
                    Senior Member
                    • Jan 2011
                    • 51

                    #10
                    Re: Replaced bulging caps, and pop... nothing

                    Also check this fuse, the live wire goes through this fuse before anything else.
                    Its probably blown, but without finding out the cause, it will probably blow again.

                    mastertheknife.
                    Attached Files
                    Last edited by mastertheknife; 01-28-2011, 11:07 AM.

                    Comment

                    • Trinite
                      Senior Member
                      • Dec 2010
                      • 143

                      #11
                      Re: Replaced bulging caps, and pop... nothing

                      That switcher MOSFET looks a bit fishy to me. If you can get a close look at it, check for any pitting, cracks or discoloration. Also check the fuses (anything labeled with an "f" on the PCB) for continuity. An open fuse will indicate that it is more likely a silicon failure than a capacitor failure.

                      Comment

                      • Rtech
                        Badcaps Legend
                        • Jul 2010
                        • 1095

                        #12
                        Re: Replaced bulging caps, and pop... nothing

                        Having worked with all sorts of electronics over many years...have never heard the term 'switcher' before.Terminology for many subjects can have different names for different things...so define 'switcher' in English please ???

                        Comment

                        • Trinite
                          Senior Member
                          • Dec 2010
                          • 143

                          #13
                          Re: Replaced bulging caps, and pop... nothing

                          Originally posted by Rtech
                          Having worked with all sorts of electronics over many years...have never heard the term 'switcher' before.Terminology for many subjects can have different names for different things...so define 'switcher' in English please ???
                          The term "switcher" is short for "switching transistor". Essentially, it is a high power transistor (generally a MOSFET type, but also can be bi-polar) that is used in combination with a PWM (pulse-width modulation) circuit.

                          Comment

                          • Rtech
                            Badcaps Legend
                            • Jul 2010
                            • 1095

                            #14
                            Re: Replaced bulging caps, and pop... nothing

                            Thanks,I know what Mosfets etc are, as I am electronics qualified,but you are the only one I have ever seen use the term on here,or anywhere else. You learn every day ....eh

                            Comment

                            • Karstedt
                              New Member
                              • Jan 2011
                              • 6

                              #15
                              Re: Replaced bulging caps, and pop... nothing

                              The fuse is definitely blown. But I don't know about what I'm assuming is the switching transistor you're talking about. It's definitely funny looking, but I don't know what it's supposed to look like. I can't read it either, so I don't what to replace it with.
                              Attached Files

                              Comment

                              • jetadm123
                                Badcaps Legend
                                • Feb 2010
                                • 2169

                                #16
                                Re: Replaced bulging caps, and pop... nothing

                                Originally posted by Karstedt
                                The fuse is definitely blown. But I don't know about what I'm assuming is the switching transistor you're talking about. It's definitely funny looking, but I don't know what it's supposed to look like. I can't read it either, so I don't what to replace it with.
                                IIRC, I believe that is a plastic cover. If you remove the screw, it should come off and expose the mosfet underneath.

                                Comment

                                • Scenic
                                  o.O
                                  • Sep 2007
                                  • 2642
                                  • Germany

                                  #17
                                  Re: Replaced bulging caps, and pop... nothing

                                  looks more like it has blown apart

                                  your only chance would be to find the missing chunk with the part number on it..

                                  Comment

                                  • Rtech
                                    Badcaps Legend
                                    • Jul 2010
                                    • 1095

                                    #18
                                    Re: Replaced bulging caps, and pop... nothing

                                    Data Sheet for the part is as follows:-
                                    http://pdf1.alldatasheet.com/datashe...FSDM0565R.html

                                    Comment

                                    • alexanna
                                      Member
                                      • Mar 2010
                                      • 1346

                                      #19
                                      Re: Replaced bulging caps, and pop... nothing

                                      https://www.badcaps.net/forum/showth...highlight=acer
                                      looks like this acer uses the same p/s
                                      wonder if samson still has to help identify parts?

                                      Don't miss Rtechs post above
                                      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                                      Comment

                                      • Rtech
                                        Badcaps Legend
                                        • Jul 2010
                                        • 1095

                                        #20
                                        Re: Replaced bulging caps, and pop... nothing

                                        Used by some Acers,some Viewsonics and Hanns G HX191.....plus no doubt many others.

                                        Comment

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