LG 42PC5D request for knowlege

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  • scikris
    New Member
    • Aug 2011
    • 7
    #1

    LG 42PC5D request for knowlege

    I was wondering if I could get some advice on a problem I am having with my TV, It's a LG PDP42x40201

    Symptoms:

    Red light on
    >Pushes power button
    Green light flashes
    Green light sustains
    No picture
    Has sound

    I got the tv like this so I don't know how bright the back light should be when the screen is black, but it doesn't look like the back light is on.

    Testing:

    power going to z board
    v-s: 190.5
    v-a: 59.6
    5 v: 4.97
    (all pretty good by my judgement)

    power going to ysus board
    v-s: ~3 (decreases longer I leave multimeter lead on it)
    v-a: .57
    5 v: 4.97
    (indicating something is faulty)

    My thoughts are that the ysus board is probably messed up and it took out some of the y components on the power supply. So is it just a matter of replacing the power supply board, ysus board and probably the y-drive board to be safe? or are there known issues/components that I can replace to get this thing working? I don't see any bulging caps, but there is an oily residue on the ysus board.

    Thanks for any advice, I don't really want to spend nearly 200$ on these new boards when at the beginning of the day I knew nothing about tvs. I don't know if this is even the real problem, I don't see any backlight light up when I push the power button like i would expect…

    tl;dr: power supply board bad, don't see bulging caps other easy fixes? Do I have to replace ysus and y-drive boards too?
    Attached Files
    Tags: None
    • PlainBill
      Badcaps Legend
      • Feb 2009
      • 7034
      • USA
      #2
      Re: LG 42PC5D request for knowlege

      This TV appears to have problems with the hybrids, just like the previous generation did.

      My suggestion: Disconnect the power cable to the Y-Sustain and measure the voltages at the power supply. Do the same at the Z-Sustain. Also check fuses on both.

      If your preliminary diagnosis is correct, you have a problem. Y-Sustain and Y-Buffer each cost upwards of $70 from reasonably reputable sellers on eBay; the power supply costs over $100.

      I doubt it is necessary to replace the Y-buffers, the damage is usually limited to the hybrid. The 15V power supply caps should be checked. Still, the hybrid is $40, and from experience is a pain to remove.

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

        Comment

        • scikris
          New Member
          • Aug 2011
          • 7
          #3
          Re: LG 42PC5D request for knowlege

          Originally posted by PlainBill
          This TV appears to have problems with the hybrids, just like the previous generation did.
          PlainBill
          Sorry, but what is a hybrid in this context? I'm completely new to TV repair

            Comment

            • PlainBill
              Badcaps Legend
              • Feb 2009
              • 7034
              • USA
              #4
              Re: LG 42PC5D request for knowlege

              Originally posted by scikris
              Sorry, but what is a hybrid in this context? I'm completely new to TV repair
              See the big black heat sinks in the second and third pictures? The hybrids are under there.

              PlainBill
              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                Comment

                • cadillacman
                  Badcaps Veteran
                  • Feb 2011
                  • 524
                  #5
                  Re: LG 42PC5D request for knowlege

                  check the fuses on the sustain boards....(use a ohmmeter) find a blown one? thats the board with issues. Most likely the hybrid, but i have seen these have smd stuff fail on them as well..

                  this set does not have a backlight(its a plasma), the light is actually generated within the panel itself.

                  its ok rookie mistake, untill about 2 months ago i did not know that either...
                  Last edited by cadillacman; 08-15-2011, 07:43 PM.

                    Comment

                    • b700029
                      Banned
                      • Sep 2010
                      • 640
                      #6
                      Re: LG 42PC5D request for knowlege

                      Sorry for grave digging, but I have same TV and same issue. I feel confident to locate and replace bulged caps, but not much after that.
                      I wonder if OP ever fixed the issue and what his solution was

                        Comment

                        • fierce
                          Member
                          • Nov 2012
                          • 14
                          • us
                          #7
                          Re: LG 42PC5D request for knowlege

                          I have the same tv with what sounds like the same problem,green light flashes 5 times,but the screen won't turn on. I have a few other LGs are the Hybrids interchangeable? What other problems could I have? No blown fuses by the way.

                            Comment

                            • tom66
                              EVs Rule
                              • Apr 2011
                              • 32560
                              • UK
                              #8
                              Re: LG 42PC5D request for knowlege

                              The hybrids are usually interchangeable if the boards are the same, sometimes if the pin outs match but I wouldn't guarantee it.
                              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                Comment

                                • fierce
                                  Member
                                  • Nov 2012
                                  • 14
                                  • us
                                  #9
                                  Re: LG 42PC5D request for knowlege

                                  The pins are all the same,so is the writing on the back of the board labeling all the pins.

                                    Comment

                                    • tom66
                                      EVs Rule
                                      • Apr 2011
                                      • 32560
                                      • UK
                                      #10
                                      Re: LG 42PC5D request for knowlege

                                      Is it from same or bigger screen size? It should be OK.
                                      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                        Comment

                                        • fierce
                                          Member
                                          • Nov 2012
                                          • 14
                                          • us
                                          #11
                                          Re: LG 42PC5D request for knowlege

                                          It's from the same size screen,almost the exact same looking board

                                            Comment

                                            • tom66
                                              EVs Rule
                                              • Apr 2011
                                              • 32560
                                              • UK
                                              #12
                                              Re: LG 42PC5D request for knowlege

                                              Then it is likely to work.
                                              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                                Comment

                                                • fierce
                                                  Member
                                                  • Nov 2012
                                                  • 14
                                                  • us
                                                  #13
                                                  Re: LG 42PC5D request for knowlege

                                                  Ok thanks,now I just gotta get them off the boards

                                                    Comment

                                                    • fierce
                                                      Member
                                                      • Nov 2012
                                                      • 14
                                                      • us
                                                      #14
                                                      Re: LG 42PC5D request for knowlege

                                                      So are the Hybrids the same as far as which sides they're on (looking at the back of the tv),like can I take one from the left side and put it on the right side?

                                                        Comment

                                                        • tom66
                                                          EVs Rule
                                                          • Apr 2011
                                                          • 32560
                                                          • UK
                                                          #15
                                                          Re: LG 42PC5D request for knowlege

                                                          Not as far as I'm aware...
                                                          Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                                          For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                                            Comment

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