50PB560B -LG common problems?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • dick_barton
    Badcaps Legend
    • Aug 2015
    • 6642
    • Wales

    #41
    Re: 50PB560B -LG common problems?

    That seems awful low but I'm unfamiliar with the layout of this buffer. Normally it is measured across a resistor.
    Perhaps someone else could offer advice here.

    The only other thing is to try and get the set two switch on again and then measure +Vsc once again.

    The white label on the back of the panel can you post a picture of it because it does give information.
    Willing to help but I'm no expert.

    Comment

    • dick_barton
      Badcaps Legend
      • Aug 2015
      • 6642
      • Wales

      #42
      Re: 50PB560B -LG common problems?

      Just seen this in another post relating to this model. To run the self test successfully
      Originally Posted by tvtimmy View Post
      Unplug the ldvs cable(flat one) that runs from the Main board to the control board and put a piece of wire in the holes on control board marked r451 and r452. If you have test patterns and colored screens your main board is bad.

      Hi, did what you suggested, and still wouldnt turn on, so unplugged the cable from PSU to main board, and it turned on, then did what you said and got test patterns
      Willing to help but I'm no expert.

      Comment

      • jp_fizzer
        Member
        • May 2020
        • 17
        • Saudi Arabia

        #43
        Re: 50PB560B -LG common problems?

        Originally posted by dick_barton
        Just seen this in another post relating to this model. To run the self test successfully
        Ok, I tried what the other poster did. I unplugged both the ribbon cable between control board and main board as well as the cable between power supply board and main board, inserted the jumper and plugged in TV. Nothing happened.

        Then I connected everything back up again and the TV turned on. Since it was powered up I retested the voltages on the Y buffer board. The Vy is still 190V but the Vsc is very strange. When I put red probe on Vsc and black on chassis the meter just bounces on DC setting so I tried switching to AC and it is pretty steady around 120VAC, which is the line voltage I am plugged into. I switched back to DC and reversed the probes so black on Vsc and red on chassis, it is bouncing around 6-8 VDC.

        Edit: I re-tested Vsc, this time using my Fluke T5 which has voltage autoselection and it is giving me 113VAC, so definitely it is thinking it is AC basically line voltage. This is while the TV is working.
        Last edited by jp_fizzer; 05-15-2020, 10:57 AM.

        Comment

        • jp_fizzer
          Member
          • May 2020
          • 17
          • Saudi Arabia

          #44
          Re: 50PB560B -LG common problems?

          Here is the white label
          Attached Files

          Comment

          • dick_barton
            Badcaps Legend
            • Aug 2015
            • 6642
            • Wales

            #45
            Re: 50PB560B -LG common problems?

            All your voltages appear to be good other than Vsc whcih I'm unsure how or where you measure it. Hopefully someone else can provide an answer.
            The other person did get the test pattern to run so I'm suspicious of your logic board.
            At this point I am out of any further ideas but hope you get some more help from other forum users.
            Last edited by dick_barton; 05-15-2020, 11:13 AM.
            Willing to help but I'm no expert.

            Comment

            • jp_fizzer
              Member
              • May 2020
              • 17
              • Saudi Arabia

              #46
              Re: 50PB560B -LG common problems?

              Here is where I am measuring Vsc on the Y buffer board. You can see from the picture that I get -23VDC when the TV is powered up but not working and I get 113VAC when the TV is working. Now the 113VAC does not seem to be related to the line voltage because I have tried it plugged into both 110V mains and 220V mains and this Vsc voltage reads the same.

              Does this Vsc voltage provide any clues about what could be the problem?

              Any suggestion what to test next? I have left the TV on in case there are any tests while it is on. As soon as I turn it off it will take many tries to get it to come back on again.
              Attached Files
              Last edited by jp_fizzer; 05-16-2020, 06:24 AM.

              Comment

              • dick_barton
                Badcaps Legend
                • Aug 2015
                • 6642
                • Wales

                #47
                Re: 50PB560B -LG common problems?

                If the set powers up and all the voltages appear to be correct and if we ignore Vsc for a moment, what you do know is that the set will not go into self-test mode, then perhaps there's a problem with the Logic board.
                Willing to help but I'm no expert.

                Comment

                • jp_fizzer
                  Member
                  • May 2020
                  • 17
                  • Saudi Arabia

                  #48
                  Re: 50PB560B -LG common problems?

                  Is there any known way to test the logic board? It looks like I could buy one for around $50 with shipping but it would be kind of nice to confirm that it was the problem before spending this.

                  Comment

                  Related Topics

                  Collapse

                  • Rene77
                    GTX 680 problems, Wrecks main board
                    by Rene77
                    i tested this Asus gtx 680 which came with a bunch of computer stuff.

                    When i only connected the 8 pin, the PC still started and gave the error on the display that also the 6 pin needed power.
                    when all connectors where powered and both leds were green, the PC did not boot, Fans where running, but nothing else.
                    Even when removing the GTX this failure kept on the main board.
                    No boot, no beeps, only the fans running, nothing else.

                    main board was a Asus B85m-G, PSU 650 Watt.

                    Tried a second (old) main board with a dual core, same...
                    12-29-2022, 02:18 AM
                  • cmlewis89
                    LG 47LB5DF blown power supply board
                    by cmlewis89
                    Hi folks,

                    I'm new to this forum. So my trusty 17-year-old LG 47" LCD recently died. As I was booting it up, I heard a hum followed by a loud bang, sounds of pieces flying around, and loss of power to the unit. Inspecting the PSU, I saw two obvious problems: a blown thermistor (bang + flung pieces) and a visibly bulging main cap. Inspecting as many components as I could with my Fluke MM, I diagnosed that the following components on the "hot side" of the board were also bad: one of the 2 main MOSFETs, main 8A fuse, small cap (25V 47uF) connected to main caps, and a blown...
                    09-03-2024, 07:50 PM
                  • Dani_2024
                    Sceptre U550CV-UMR 4K LED, Bad Caps on Main Power Board?
                    by Dani_2024
                    Hi and thanks in advance for any input you might provide!
                    I have a Sceptre U550CV-UMRD8POTV83BB 4K LED (this is a dumb tv) that I bought new in August 2021, so It's just completed 3 years.
                    Main power board model: TP.MS3683.PC821 T-Con board: N4TP546UHDPU2L_BO

                    Last Sunday I was watching a dvd and fell asleep for about half hour, when I awoke the tv screen was black and couldn't get the dvd menu to show, so I changed the input to antenna and had sound but no picture, turned it off. I then got online and found this great site! ....read many troubleshooting tips and this...
                    10-28-2024, 05:06 PM
                  • cheeky2
                    Is it possible to upgrade from a Vestel 17MB97 main board to a 17MB110 Main board?
                    by cheeky2
                    I suppose the real question is whether the existing pinouts from ether a 17IPS71 psu are cross compatible with a 17IPS12 psu? If they are then the exchange of the main boards should have no issues providing the screen is compatible with both main boards. Obviously you can change the screen configurations easily enough (providing you have the correct files) for the main board. Why may you ask would I do this? Well a lot of the smart features are no longer working on a Hitachi 48HBT62U main board I wish to give it a new lease of life!
                    Obviously the same LVDS connector for the screen connection...
                    05-25-2024, 03:27 AM
                  • Matthieu vK
                    repairing 360 s6 vacume cleaner robot with stuck radar
                    by Matthieu vK
                    Hello,

                    I got my hands on a 2e hand 360 s6 vacuuming robot i wish to repair.

                    Unfortunately, a common (and mine) problem is that the radar, used for navigation is not working.
                    a second unfortunate thing is these problems seem to have many different causes, from dirty lens, to stuck hairs so it can't move, to broken down radar module to a faulty PWM (mosfet?).

                    the issue I am dealing with is what I believe to be a faulty PWM.
                    I have come to this conclusion as this seems to be an issue that others have dealt with also, but I have not found anyone...
                    04-29-2024, 05:32 PM
                  • Loading...
                  • No more items.
                  Working...