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Philips 32PF3320/10 bad colors / too bright

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    Philips 32PF3320/10 bad colors / too bright

    Hello!

    A friend of me gave me an old television, he told me, that it's not working. It's an Philips 32PF3320/10 TFT LCD TV.

    Since I like to fix stuff, I decided to fix this TV too. I plugged it in, it turned on, I got backlight and also, sound. The only thing that didn't work is the screen itself; it had nothing on it.

    After I took it apart, I noticed, that everything seems okay, so I got to the T-con board. The model is: V32BC3 (the big chip version).

    The F1 fuse was blown, but I didn't find any shorts on the board, so I just replaced it with a cable for testing purposes. (I know that it blew for a reason)..

    After turning the TV on like this, I now have picture, and can confirm that the TV is in fact working in general, but the colors are waaaaay off.. It's like the picture had a white fog in front of it. It's hard to see.
    Also, if say, I open the menu for 10 seconds, then close it, the menu won't fully disappear, like it burns into the screen.. (picture attached)

    I have read some forums and watched videos, and I saw that the AS15-F chip can die and produce this, so I replaced it, but the problem remained.

    I didn't meausre everything yet, because I had to go to work, but I can confirm, that between GAM2 and GAM17 everything seemed fine about the voltages. But then I noticed, that the GAM1 and GAM18 is at a completely different spot on the board!

    The GAM2-GAM17 testpoints are connected to the AS15-F chip and they are located at the left side of the board (blue marking on picture), however, the GAM1 and GAM18 points are on the right side of the board, and connected to the AS34-G chip. (marked with red).

    And the voltages seem switched to me.. the GAM1 has 0V, while GAM18 has ~14.7.
    Meanwile, on the other side of the board, GAM2 has ~14V, and GAM17 has ~0.7V.

    I might not understand everything completely here, but what do you say? On the hungaian TV forum they told me it's a bad LCD and its not fixable.

    Important note: i tested the voltages without the LCD connected.

    Thanks in advance,
    Dominik.
    Attached Files

    #2
    Re: Philips 32PF3320/10 bad colors / too bright

    I see the AS34-G referenced as a gamma correction IC, if replacing the AS15-F hasn't made any difference then I'd change the AS34-G.

    Comment


      #3
      Re: Philips 32PF3320/10 bad colors / too bright

      So, I ordered a new AS34-G chip, but since it's from aliexpress, it's gonna be at least a month till it arrives.

      However, I measured a lot more things than yesterday, like all the VGAM points an others.

      I made a graph with the VGAM voltages, you can see the attachments.
      Note: the GAM1 and GAM18 are connected to the AS34-G chip, and not the AS15-F chip.

      But I am not sure, which side of the chip is an input or output, nor how it really works, since there is not much information about it.

      Other voltages I measured:

      VGL -6.3V
      VGH 33.5V
      VLS 14.9V
      VCOM2 0.17V (this is the other side of the AS34-G chip)
      VCOM3 0.4V (this is the other side of the AS34-G chip)
      D_VDD_F 3V

      There are a few more testpoints, that I could measure, like VCOM1 and a few other one, but now I'm a bit concerned, if it's the T-con board or not.
      Attached Files

      Comment


        #4
        Re: Philips 32PF3320/10 bad colors / too bright

        That voltage graph looks ok untill VGAM18, that voltage should likely be around 0.5 and not 15v

        Comment


          #5
          Re: Philips 32PF3320/10 bad colors / too bright

          I looked at the t-con board picture and I only see GAM2~GAM17 where did the GAM1 & GAM18 come from? It would seem that the GAM voltages are ok and the graphed voltages are missleading.
          Have you tried disconnecting (with power off) the cables between the t-con and the panel, try them one at a time and see if it makes a difference to the video ojn the screen.

          Comment


            #6
            Re: Philips 32PF3320/10 bad colors / too bright

            As I mentioned, the GAM1 and GAM18 are on the right side of the board, but I'm gonna attach a picture again, with them highlighted.

            Yes, I tried connecting only one side of the screen, but that didn't make a difference.

            Some new information: I have read that the VCOM voltages should be like ~7V, however, I have ~0V on the VCOM2 and VCOM3 (didn't measure VCOM1 yet). Could this make this problem?
            Attached Files

            Comment


              #7
              Re: Philips 32PF3320/10 bad colors / too bright

              So, today I changed the AS34-G to a new one, and it fixed the problem! ...well, for a few minutes. Then, again, the picture got weird. Not as bad, as before, but definitely brighter than it should be. I was checking the GAM18 voltage, while it was good, the voltage was around 0.6V.

              Then, now, with the messed up picture, it's now around ~6V, so now I am pretty sure, that the GAM18 voltage is the problem. I got another spare chip, and I'm gonna try that one too, and if that also fails, at least I will know, that the GAM18 line is the one to fiddle with.

              EDIT: i put in the other chip, and now the colors are fine! And it worked so far. However, there are some weird flickering on the top middle part of the screen, I also see some horizontal lines on that area... it might be the burn in from the previous chip, so I'm gonna turn the TV off for a few hours, and then turn it back on.
              However, if it will still do this same thingy, I'm giving up on it.
              Last edited by dominik0801; 03-24-2020, 10:45 AM. Reason: new info

              Comment


                #8
                Re: Philips 32PF3320/10 bad colors / too bright

                Last post about the TV, since I call this a win situation and a working TV from now!

                So since the colors were okay, and the only problem was the picture lining and the vibrating area, I opened up the TV again, and started to turn the pot on the LCD's top PCB, and it suddenly stopped the vibration and the lines went away too.

                I know, that my thread is a bit messy, and it's mostly just me telling unnecessary informations, but maybe someone else will find these posts and help them too.

                Comment


                  #9
                  Re: Philips 32PF3320/10 bad colors / too bright

                  Originally posted by dominik0801 View Post
                  Last post about the TV, since I call this a win situation and a working TV from now!

                  So since the colors were okay, and the only problem was the picture lining and the vibrating area, I opened up the TV again, and started to turn the pot on the LCD's top PCB, and it suddenly stopped the vibration and the lines went away too.

                  I know, that my thread is a bit messy, and it's mostly just me telling unnecessary informations, but maybe someone else will find these posts and help them too.
                  "LCD's top pcb" ?
                  What "pot" did you adjust? Is there a pot on the board on the lcd panel board? This is the board between the t-con and the lcd panel itself.

                  Comment


                    #10
                    Re: Philips 32PF3320/10 bad colors / too bright

                    Yes, between the T-Con and LCD panel, there was a PCB. It only had 1 pot, which seemed to be a pot to set the VCOM voltage.
                    After fiddling with it, the picture became good, and working ever since.

                    Comment

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