LG 60LB5200 will not turn on

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • WTRWLKR
    Member
    • Dec 2017
    • 24
    • USA

    #1

    LG 60LB5200 will not turn on

    LG 60LB5200 will not turn on. There is a green standby light.

    Measured voltages at the power supply output connector. All 12V pins were at 7V. All 24V pins were at 15.5V. EN pin is at 2.2V

    Does this appear to be a faulty power supply or is there something else I need to look at?
    Attached Files
  • maxvalutech
    Badcaps Veteran
    • Dec 2014
    • 804
    • australia

    #2
    Re: LG 60LB5200 will not turn on

    Are you happy your dmm is reading correctly ? Then measure voltage across the two largest caps - neg on lhs pin pos on rhs pin - should get 350/400v.

    Comment

    • WTRWLKR
      Member
      • Dec 2017
      • 24
      • USA

      #3
      Re: LG 60LB5200 will not turn on

      To be safe, I used a different meter. Voltages were much the same.

      Here are the actual voyltages, instead of my memory.

      12V = 6.95V
      24V = 15.64V
      EN = 2.54V

      Both of the large caps are 163.2 VDC

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #4
        Re: LG 60LB5200 will not turn on

        Your PFC Voltage booster is not working.
        Check the RESISTANCE of the Diode D12 in both direction.
        We also need good clear picture of the bottom side of the board.
        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

        • WTRWLKR
          Member
          • Dec 2017
          • 24
          • USA

          #5
          Re: LG 60LB5200 will not turn on

          Do I need to remove D12 from the board, before testing it?

          Power removed, D12 still on the board
          Negative on cathode: 30k or 239k (it changes between them)
          Positive on the cathode: started at 250k and climbed to over 1M, before I stopped measuring it.
          Attached Files
          Last edited by WTRWLKR; 12-12-2017, 06:57 PM.

          Comment

          • WTRWLKR
            Member
            • Dec 2017
            • 24
            • USA

            #6
            Re: LG 60LB5200 will not turn on

            I guess I must have stumped the veteran members with this one. It's been about 30 years, since I last dealt with electronics at this level.

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: LG 60LB5200 will not turn on

              OK, PFC diode is OK.
              Get the P/N as printed on the U1 SMD IC and then look up the spec sheet so you can find out which pin of the IC is the VCC pin so you can verify if the IC is getting the power to run it or not when the TV is turned on.
              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

              • WTRWLKR
                Member
                • Dec 2017
                • 24
                • USA

                #8
                Re: LG 60LB5200 will not turn on

                Looks like an NXP TEA1755T

                Pin 1 Vcc = 1.15V
                Pin 5 LATCH = 1.10V
                Attached Files

                Comment

                • WTRWLKR
                  Member
                  • Dec 2017
                  • 24
                  • USA

                  #9
                  Re: LG 60LB5200 will not turn on

                  Is the Vcc good or bad? Do you need me to get other voltages?

                  Thanks for your guidance.

                  Comment

                  • maxvalutech
                    Badcaps Veteran
                    • Dec 2014
                    • 804
                    • australia

                    #10
                    Re: LG 60LB5200 will not turn on

                    Service manual at manualslib may help with diagnosis. It is slightly different model but PSU may be much the same.
                    Attached Files
                    Last edited by maxvalutech; 12-21-2017, 05:06 PM.

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: LG 60LB5200 will not turn on

                      Originally posted by WTRWLKR
                      Looks like an NXP TEA1755T

                      Pin 1 Vcc = 1.15V
                      Pin 5 LATCH = 1.10V
                      It is not getting way too low of the Voltage to run, so the next thing will be tracing out the VCC pin back to switched Transistor on that power supply board to see if it is getting the Voltage feeding it and the control Voltage to turn it on or not. This is not going to be easy for beginner unless you are really good at tracing out the board.
                      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

                      • WTRWLKR
                        Member
                        • Dec 2017
                        • 24
                        • USA

                        #12
                        Re: LG 60LB5200 will not turn on

                        I was able to trace Vcc to a nearby transistor. Is it the one you are needing voltages from, or did I miss it by a long shot?
                        Attached Files

                        Comment

                        • WTRWLKR
                          Member
                          • Dec 2017
                          • 24
                          • USA

                          #13
                          Re: LG 60LB5200 will not turn on

                          maxvalutech, I looked at the manual. It appears to get into everything except the power board.

                          The only reference that I found for the power board was a statement of if power on voltage is not 3.5V, replace the power board.

                          Comment

                          • maxvalutech
                            Badcaps Veteran
                            • Dec 2014
                            • 804
                            • australia

                            #14
                            Re: LG 60LB5200 will not turn on

                            Page 27 of sm gives a bit of circuitry for 3.3 vcc

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #15
                              Re: LG 60LB5200 will not turn on

                              What DC Voltage do get between the two legs of the cap I circle in red?
                              The Voltage on that cap is generated from the AUX winding of the STBY Transformer.
                              Attached Files
                              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

                              • WTRWLKR
                                Member
                                • Dec 2017
                                • 24
                                • USA

                                #16
                                Re: LG 60LB5200 will not turn on

                                I hope everyone had a great Christmas.

                                I think I used a bad ground point for Vcc. Using PIN 1 for Vcc and PIN 2 for ground, I get 14.49V.

                                I measured across the cap and get 15.1V.

                                Comment

                                • WTRWLKR
                                  Member
                                  • Dec 2017
                                  • 24
                                  • USA

                                  #17
                                  Re: LG 60LB5200 will not turn on

                                  Are these the expected voltages?

                                  What voltages should I look at next?

                                  Thank you

                                  Comment

                                  • WTRWLKR
                                    Member
                                    • Dec 2017
                                    • 24
                                    • USA

                                    #18
                                    Re: LG 60LB5200 will not turn on

                                    Have I stumped the experts?

                                    Comment

                                    • budm
                                      Badcaps Legend
                                      • Feb 2010
                                      • 40746
                                      • USA

                                      #19
                                      Re: LG 60LB5200 will not turn on

                                      So the IC is getting the VCC to run but it is not running.
                                      Report the other pins Voltages too to see if they are what they should be or not, make sure to use good GND this time.
                                      Last edited by budm; 01-18-2018, 10:41 AM.
                                      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

                                      • WTRWLKR
                                        Member
                                        • Dec 2017
                                        • 24
                                        • USA

                                        #20
                                        Re: LG 60LB5200 will not turn on

                                        Got it. I will use Pin 2 for the ground point and record the voltages of all other pins.

                                        I will do that after I get home tonight and post the results.

                                        Comment

                                        Related Topics

                                        Collapse

                                        • pajdek
                                          Lenovo Y700-17ISK turn on and off
                                          by pajdek
                                          Hello, i have some issues with my laptop Lenovo Y700-17ISK (motherboard BY511 NM-A541), it started when i turn on the laptop, but the lcd wont turn on, i then connected it via hdmi to tv and screen was ok. So i thought maybe lcd stripe is faulty, i removed the bottom cover, disconnected main battery, reset the cmos by disconnecting battery for 1 min, then slighty move the lcd stripe. Conncted power supply and tuned on my laptop, the lcd turn on, it started to load os, then it turn off, after a second it turn on, then after like 3 seconds turn off again, and so on. Removed power supply, waited...
                                          09-20-2023, 02:49 AM
                                        • RdeveLabs
                                          MSI GF63 THIN 11UCX (MS-16R6) LAPTOP WON'T TURN ON AFTER RESTARTING
                                          by RdeveLabs
                                          To all the members here...

                                          Let me tell you a little bit about what happened to my laptop (MSI GF63 THIN 11UCX model: MS-16R6) that “maybe” you know how to solve this problem.

                                          So before this problem happened, my laptop was running smoothly. When I wanted to restart my laptop, it looked fine at first. But after I waited for this restart process to take a long time, until finally I panicked (because the restart process did not finish plus the laptop screen only showed a black screen), I immediately pressed and held the power button to force the laptop to turn off. But...
                                          05-05-2025, 04:59 AM
                                        • robante15
                                          Acer Aspire 4520 won't turn on after reboot
                                          by robante15
                                          Hello, I have an Acer Aspire 4520 from a couple of decades ago and I want to repair it solely for nostalgia.

                                          It happens that when I turn it on after having been disconnected for a long time, it turns on without problems, it tells me that the BIOS has been reset and that it will load the factory settings, if I tell it to continue, the computer turns on and everything works fine.

                                          The moment I turn it off and want to turn it back on a second time, or restart it and try to start it again, it no longer gives an image, and it no longer responds.

                                          If I remove the...
                                          04-06-2024, 06:50 PM
                                        • masoksian
                                          Dell latitude e7470 not turn on .power buton on off and Run Power problem
                                          by masoksian
                                          Hi everyone,

                                          I am dealing with the problem of turning on and off my Dell e7470 notebook.

                                          The battery charge light is solid white, I press the button, the power indicator and the light on the button are solid for 1-2 seconds and immediately turn off.

                                          The system does not turn on, there is no post.

                                          I removed the RAMs and changed them, changed the battery, RTC battery, AC adapter, removed them and waited, tried again, it does not turn on.
                                          The problem continues in the same way.
                                          I tried to turn on the Fn key, nothing came to the screen....
                                          02-15-2025, 12:08 PM
                                        • dqtech
                                          lenovo x240 nm-a091 wont turn on
                                          by dqtech
                                          i got this laptop with no power issue....i flashed the bios and laptop can turn on and use normally....but when i shut it down and rest for few minute (2-3 minutes), it wont turn on....i have to flash bios again...any idea what is the problem?...when i shutdown and suddenly press power button to turn on, it will turn on normally....problem happen when i rest the laptop 2-3 minutes after shutdown, it will not turn on....i need to flash bios again
                                          board number VIUX1 NM-A091 REV:1.0...
                                          02-07-2024, 01:57 AM
                                        • Loading...
                                        • No more items.
                                        Working...