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Philips 50" Plasma bottom half of screen is black

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    Philips 50" Plasma bottom half of screen is black

    I acquired a 50" Philips plasma, model number 50PF9630A/37 a couple months back. Short background on it: my fiance's sister is a manager at an apartment complex near her college. When people move out and leave items, they raffle it off. They "tested" the TV and confirmed it worked, raffled it off and she won. Being a 135lb behemoth made in 2005, she had no use for it, so she let me take it.

    After moving the monster inside, I plugged it in to power and to cable, to test it out. Worked great.

    A few days later, I went ahead and moved it to my old fraternity house from college (they needed a new TV and this was free). Plugged it in, and after some fancy plug/un-plug trickery, I got it to turn on.

    Had the cable box connected, and other than some odd moments where switching from SD to HD would cause a black screen (which was fixed mostly by restarting the cable box), it was working great. About 20 minutes later, the bottom half of the picture went black. I tried unplugging it and plugging it back in, and that's when I noticed it wouldn't always turn on, instead flashing the LED at me, and staying off. I read online this was likely caps on the power board, so I ordered some up, and they were soldered into the board to replace the visibly-bursting old ones.

    So now, the television starts up great, as it should, every time. Unfortunately, the bottom half of the television is still black. On the very bottom, the last row or two of pixels is purple (not consistently all the way across, it varies a bit), like signal is trying to make it's way upwards, but the rest of the bottom half of the picture is black (I can have pictures taken, if needed). The top half works perfectly fine, as does sound and everything else.

    We took it apart again last night, and replaced the Lower Y-buffer board with a working one I bought off ebay - same part number - just one revision newer (so it had the small white connector at the top - something the original board does not have). Put the cover back on, put a few screws in, and alas - still the same problem. So it seems like the lower Y-buffer is not the issue.

    Any thoughts on what could be causing this and/or how to fix it? It's a nice television and had a great picture for it's age, when it worked, but having half a picture doesn't help when trying to watch a program, haha.

    Thanks,

    Kyle

    (Again, if pictures are needed, let me know, and I'll get a few).

    #2
    Re: Philips 50" Plasma bottom half of screen is black

    That is not the proper buffer board. It requirs data to be driven to the buffer via top buffer. Need.to get the proper buffer board for that model. Same rev number.
    Did I leave the soldering iron on?

    Comment


      #3
      Re: Philips 50" Plasma bottom half of screen is black

      That would make sense. That would also mean that it was listed incorrectly on eBay (Rev was not listed, but the TV's model number was, which was the same as what I have).

      So it's possible, that if I got the previous rev, it may work?
      Last edited by MP81; 11-27-2013, 12:01 PM.

      Comment


        #4
        Re: Philips 50" Plasma bottom half of screen is black

        Yes, there are two variants of buffers. One which is individually fed and one which is chained.
        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


          #5
          Re: Philips 50" Plasma bottom half of screen is black

          So my first test would be to get another board, but of the correct revision this time, and try that?

          Comment


            #6
            Re: Philips 50" Plasma bottom half of screen is black

            Indeed

            Comment


              #7
              Re: Philips 50" Plasma bottom half of screen is black

              Thanks. I'll post what the results are once I've gotten ahold of a new board and installed it.

              Comment


                #8
                Re: Philips 50" Plasma bottom half of screen is black

                Try ordering by the PBA CODE LJ9x-xxxxxx part # rather than by the model # of the set.
                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


                  #9
                  Re: Philips 50" Plasma bottom half of screen is black

                  That's actually what I did before. Maybe they switched to the newer revision later in the model's production run. I found one that I believe is the correct rev this time. Just have to double check when I get home and then I can go ahead and purchase that.

                  Comment


                    #10
                    Re: Philips 50" Plasma bottom half of screen is black

                    Just try to use PBA code over PCB code. PBA is for the whole assembled board, PCB is just for the bare board with no components added.
                    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


                      #11
                      Re: Philips 50" Plasma bottom half of screen is black

                      The timing of this thread couldn't be any better. If these pics are anything like what you describe, I'm going through the same issue. Only I just bought this tv in this condition. I have no idea if the buffers are right or wrong for this TV (50PF9630A/37).

                      I don't have the buffer part numbers right now, but I'll get them and post what is installed. There were indications(missing screws, stripped screws etc) showing that the previous owner had been inside. I called and he stated that his cousin replaced what he believes was a Y-Buffer board.







                      Comment


                        #12
                        Re: Philips 50" Plasma bottom half of screen is black

                        Looks like the topmost buffer chip is on its way out and the bottom has gone as well. Be careful running it like that too long. The buffer chip failure can damage the Y-main.
                        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


                          #13
                          Re: Philips 50" Plasma bottom half of screen is black

                          Thanks for the advice. I am highly skeptical of the eBay boards, and don't want to deal with extra damage when it turns out the used board toasts the main board. So, I have decided (possibly foolishly) to replace all the ICs on the upper and lower boards. I found a very reasonable deal on chips. Let's hope this doesn't bite me in the end... http://m.aliexpress.com/item/1455351...bilesitedetail

                          I suppose if I'm going through this much trouble, I should test the Y-main board for toasted FETs...

                          Comment


                            #14
                            Re: Philips 50" Plasma bottom half of screen is black

                            All right,

                            So the correct revision buffer board didn't fix it either. What's next on the list of potential causes?

                            Also, I took a picture of what it looks like when it's on (picture quality sucks, but you can see the issue just fine).

                            Thoughts?
                            Attached Files

                            Comment


                              #15
                              Re: Philips 50" Plasma bottom half of screen is black

                              That lit up line makes me wonder if the panel is bad, perhaps an internal electrode short. Can't think of much else that would cause that with two buffers.
                              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


                                #16
                                Re: Philips 50" Plasma bottom half of screen is black

                                Cause it wouldn't make sense that it's the larger board that drives the two Y buffers, right? What about the long board along the bottom?

                                What's weird is that it did work for about 30 minutes back when I first brought the TV over...that's what throws me...

                                Comment


                                  #17
                                  Re: Philips 50" Plasma bottom half of screen is black

                                  Possibly a hairline fracture of the panel obtained in transit... after 30 mins the heat caused it to worsen and short

                                  Comment


                                    #18
                                    Re: Philips 50" Plasma bottom half of screen is black

                                    Is that last pic taken with the lower buffer removed from the tv? if so I would have to agree with Tom, panel short.If not, remove the lower buffer board altogether and retest, bottom of the screen should be all black.
                                    Did I leave the soldering iron on?

                                    Comment


                                      #19
                                      Re: Philips 50" Plasma bottom half of screen is black

                                      No, that picture is with the lower buffer in there.

                                      So what would removing the buffer prove. If the purple at the bottom is still there, then it's a panel short?

                                      Comment


                                        #20
                                        Re: Philips 50" Plasma bottom half of screen is black

                                        Let's say...prior to covering the buffer chip pins with Rtv, you powered the set on because you read that other people had done the same with no Ill effects, however when you yourself try it, you hear arcing sounds... On the Y-main board, towards the buffer output, you find a blown fuse on the lower half, of the board, and post replacing fuse, and covering all pins with Rtv, the fuse doesn't blow, but the tv also won't light the screen? I'm getting good voltages out of the PS, and the logic board has one steady lit led, as well as one blinking. The alarm board led is steady lit, which doesn't seem to mean much since of all the ( I assume) blink codes, steady is not one of them. 1 would mean VA, which should be 70v, and it measures 70.1. Soooo, just how messed up is this tv now! (All 5 fuses on the Y-Main are in tact.... Additionally, the standby Led on the front of the tv turns on and off with the remote, there are no red lights.

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