LG 42LV5500 TV - black screen, no sound, no image, no backlight

Collapse
X
Collapse
 
  • Page of 2
  • Time
  • Show
Clear All
new posts
Previous 1 2 template Next
  • russianbot
    Member
    • Jan 2019
    • 11
    • USA
    #1

    LG 42LV5500 TV - black screen, no sound, no image, no backlight

    My LG TV 42LV5500 no longer shows anything on the screen. There is no backlight, no audio from external input sources, and using a flashlight I can't see anything on the screen either. When powering on, the status LED changes color and it makes a faint click as usual, but nothing else happens.

    The problem happened unexpectedly - everything worked ok until one day it just doesn't show anything when powering on. I took the back cover off, there's a green board (I'm guessing the main board) and a brown board (probably the power board). Don't see any bulging or leaking capacitors. I checked the 3 fuses on the power board, and they're ok.

    Any ideas what can be the problem? What else can I check to diagnose the problem?

    I uploaded photos of the two boards, and closeups of the power board.
    Attached Files
    Tags: None
    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA
      #2
      Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

      The connector on the power supply board that goes to the Main board has pin name for each pin, you need to check the Voltage on each pin when TV is OFF and when power switch is activated.
      You MUST put down the pin name and follow by the Voltage reading for each pin so we can easily see what the Voltages are.
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

        Comment

        • CapLeaker
          Leaking Member
          • Dec 2014
          • 7973
          • Canada
          #3
          Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

          Adding to budm request, turn the TV on and measure the 450V main capacitor. Be careful working there!

            Comment

            • neilc6
              Badcaps Legend
              • Nov 2015
              • 1550
              • Canada
              #4
              Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

              LV series suffers from BGA failure.on the main processor

              https://ebay.us/NkMDFB

              Main board failures our service covers:
              TV can be turned on and off, however no back-light appears, no picture, or sound
              TV turns on but picture has strange lines all all inputs and on menus
              TV Turns on, LG logo appears on screen, but then does not show any picture
              TV Turns on, but freezes on the LG Logo
              HDMI Ports have no signal

                Comment

                • russianbot
                  Member
                  • Jan 2019
                  • 11
                  • USA
                  #5
                  Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                  I measured the voltage across the 450V capacitors, they show about 400V when the TV is powered on.
                  Measured the voltages on the 24 pin connector from the power board to the main board. Here are the voltages listed below for each pin when the unit is in standby mode and when powered on. Some pins have a small AC voltage, so I listed those too.

                  Pin_____OFF_____ON
                  NC______0_______0____(0.6 - 1V AC 120Hz)
                  12V_____0_______11.89
                  12V_____0_______11.89
                  12V_____0_______11.89
                  GND_____0_______0
                  GND_____0_______0
                  3.5V____3.5_____3.5
                  3.5V____3.5_____3.5
                  GND_____0_______0
                  GND_____0_______0
                  24V_____0_______24.4
                  PWN-ON__0_______3.4
                  ERROR___0_______0
                  PWM_____0_______3.2
                  NC______0_______0____(0.6V - 1V AC 120Hz)
                  DRV-ON__0_______0.04
                  VSYNC___0_______0____(0.6V - 1V AC 120Hz)
                  GND_____0_______0
                  3.5V____3.5_____3.5
                  3.5V____3.5_____3.5
                  GND_____0_______0
                  GND_____0_______0
                  24V_____0_______24.4
                  24V_____0_______24.4



                  I might try reflowing the CPU on the main board with a heat gun, I heard some people fixed their TV that way.

                    Comment

                    • nomoresonys
                      Badcaps Legend
                      • Jan 2013
                      • 12081
                      • U.S.
                      #6
                      Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                      Looks like you're not getting proper drv-on voltage from the mainboard.

                        Comment

                        • nomoresonys
                          Badcaps Legend
                          • Jan 2013
                          • 12081
                          • U.S.
                          #7
                          Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                          Try unplug cable from powerboard to mainboard, plug tv back into outlet turn on tv, see if backlights come on and stay on.

                            Comment

                            • CapLeaker
                              Leaking Member
                              • Dec 2014
                              • 7973
                              • Canada
                              #8
                              Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                              your main board isn't sending DRV-ON signal (back lights).

                                Comment

                                • neilc6
                                  Badcaps Legend
                                  • Nov 2015
                                  • 1550
                                  • Canada
                                  #9
                                  Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                  Originally posted by nomoresonys
                                  Try unplug cable from powerboard to mainboard, plug tv back into outlet turn on tv, see if backlights come on and stay on.
                                  I believe this test only works with Samsungs. LGs dont have pullup resistors.

                                    Comment

                                    • CapLeaker
                                      Leaking Member
                                      • Dec 2014
                                      • 7973
                                      • Canada
                                      #10
                                      Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                      then force the psu on. Unhook the main board from the PSU. Put a 1k resistor from STBY to PSon and another resistor from STBY to BLon.

                                        Comment

                                        • nomoresonys
                                          Badcaps Legend
                                          • Jan 2013
                                          • 12081
                                          • U.S.
                                          #11
                                          Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                          Yep, do what CapLeaker said, make sure cable from powerboard to mainboard is UNPLUGGED during test.
                                          Last edited by nomoresonys; 03-09-2019, 04:06 PM.

                                            Comment

                                            • nomoresonys
                                              Badcaps Legend
                                              • Jan 2013
                                              • 12081
                                              • U.S.
                                              #12
                                              Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                              Originally posted by neilc6
                                              I believe this test only works with Samsungs. LGs dont have pullup resistors.
                                              Works with any tv with pullup resistors. Didn't check this exact model, quick test, no results then force on per CapLeaker's instructions.

                                                Comment

                                                • russianbot
                                                  Member
                                                  • Jan 2019
                                                  • 11
                                                  • USA
                                                  #13
                                                  Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                  Good news - I reflowed the processor on the main board, and the TV works as good as new. Thanks for everyone's help and advice.

                                                    Comment

                                                    • neilc6
                                                      Badcaps Legend
                                                      • Nov 2015
                                                      • 1550
                                                      • Canada
                                                      #14
                                                      Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                      Results may only be temporary and board will likely fail in weeks or months. Reballing is the proper repair.

                                                        Comment

                                                        • snme
                                                          Member
                                                          • Feb 2016
                                                          • 26
                                                          • AU
                                                          #15
                                                          Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                          I also have a LG 42LV5500-TA, failed whilst in operation.
                                                          AC on relay click, nothing more.
                                                          Test of backlight was ok.
                                                          Test of RBGW rotation by T-Con was ok.
                                                          So now trying to find a mainboard EBU61302301, EAX64104703 (1) without much joy.
                                                          I'm guessing from prior comments that a hair drier fan on the video processor might not be ample heat for reflow. Perhaps longer localized time?
                                                          I am in Australia Sydney.
                                                          Last edited by snme; 08-25-2023, 09:34 PM. Reason: More particularly Sydney

                                                            Comment

                                                            • nomoresonys
                                                              Badcaps Legend
                                                              • Jan 2013
                                                              • 12081
                                                              • U.S.
                                                              #16
                                                              Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                              Do test in post #10.

                                                                Comment

                                                                • snme
                                                                  Member
                                                                  • Feb 2016
                                                                  • 26
                                                                  • AU
                                                                  #17
                                                                  Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                                  Yes I have done that backlight test, also T-Con RGBW pattern test.
                                                                  Both good.
                                                                  To clarify, above tests were conducted after finding INV-ON = DRV-ON was low from mainboard.
                                                                  Last edited by snme; 08-26-2023, 06:07 PM. Reason: Clarification

                                                                    Comment

                                                                    • nomoresonys
                                                                      Badcaps Legend
                                                                      • Jan 2013
                                                                      • 12081
                                                                      • U.S.
                                                                      #18
                                                                      Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                                      Ok, well sure looks like the same issue as the op had, check out the diy reflows on youtube, need to be careful with the temps, use flux, at least look at a few, a lot of the posters know what they are doing and some don't.
                                                                      Last edited by nomoresonys; 08-27-2023, 10:19 AM.

                                                                        Comment

                                                                        • nomoresonys
                                                                          Badcaps Legend
                                                                          • Jan 2013
                                                                          • 12081
                                                                          • U.S.
                                                                          #19
                                                                          Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                                          here is a very smart young man doing one on his tv, note how he suggests the fan at the end: https://www.youtube.com/watch?v=O1XGwQszLrc

                                                                            Comment

                                                                            • diif
                                                                              Badcaps Legend
                                                                              • Feb 2014
                                                                              • 6978
                                                                              • England
                                                                              #20
                                                                              Re: LG 42LV5500 TV - black screen, no sound, no image, no backlight

                                                                              The last LV series LG is reflowed I did over 2 years ago and its still going well.
                                                                              Anything you want to know about reflowing just ask.

                                                                                Comment

                                                                                Previous 1 2 template Next

                                                                                Related Topics

                                                                                Collapse
                                                                                • m1ch43lzm
                                                                                  HP Pavilion 15-eh Board DAG7HAMB8F0 - CPU throttling to 0.4GHz (PROCHOT_EXT) and black screen
                                                                                  by m1ch43lzm
                                                                                  Hi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
                                                                                  Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic...
                                                                                  05-12-2025, 08:37 PM
                                                                                • mrtek
                                                                                  Samsung UN65js8500F, no sound, blank screen and T-Con board with one LED on
                                                                                  by mrtek
                                                                                  Hi I am new to this kind of repairs but I want to learn..I have a Samsung UN65JS8500F. the TV used to work and I tried to fix darker areas in the middle only ( img 1,2,3). I thought the led strip were bad..not the case. I did not research in advance what kind and where the LED were located. In this model they are located vertically on right and left side. Took the TV apart and put it back together. Now the tv shows no welcome screen and no sound is available thru the speakers. ..just a black screen..Backlight LED do turn on...also noticed a 5 blink code , not sure if that was there before. I can...
                                                                                  6 Photos
                                                                                  11-26-2024, 09:58 AM
                                                                                • Rozp
                                                                                  70LE660U dark cloud or black screen with sound.
                                                                                  by Rozp
                                                                                  Hello Everyone,

                                                                                  This is my first post so I will try to be as precise as possible without making this post too long winded. Unfortunately I don't have pictures of the original problem but I included images of the TV internals.

                                                                                  I have a Sharp 70LE660U. The problem started a few months ago with the bottom row looking out of sync and was dark on the left side and then fading to transparent on the right side. Shortly after, a dark cloud appeared in the center of the screen. The dark cloud started small and shaded but the image was visible. It also affected the menu area....
                                                                                  08-29-2023, 05:25 PM
                                                                                • Tynan Dill
                                                                                  Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
                                                                                  by Tynan Dill
                                                                                  I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

                                                                                  Upon bringing it home and plugging it up, it showed a standby light.

                                                                                  I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

                                                                                  The screen seems to blackout and stay black, but with a flashlight I can see the display.

                                                                                  With my Playstation 4 connected via HDMI, and running a game I can hear sound.

                                                                                  Assuming...
                                                                                  ORIGINAL POWER SUPPLY BOARD
                                                                                  7 Photos
                                                                                  11-22-2024, 01:46 PM
                                                                                • spice_disc
                                                                                  Vizio TV M50-C1 reboot cycle and static on screen
                                                                                  by spice_disc
                                                                                  I'm currently trying to diagnose and fix my Vizio TV (Model M50-C1). I've tried a number of different basic solutions, but I'm trying to determine if my issue is currently a failing panel, T-Con board, or main board (or something else entirely) and whether or not it is worth my time to fix it. Details of the issue and what I've tried are below as well as why I think it is either a bad panel, T-Con board, or main board.

                                                                                  The Issue: The TV will be on and working fine but after the TV is on for ~5-10 minutes the screen will freeze (with sound continuing) until the TV reboots itself. While...
                                                                                  1 Photo
                                                                                  09-08-2024, 02:37 PM
                                                                                • Loading...
                                                                                • No more items.
                                                                                Working...