sharp lc-40sh340k Baclight Ptoblem.

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • Mikeyboy2007
    Badcaps Veteran
    • Mar 2013
    • 745
    • Scotland
    #1

    sharp lc-40sh340k Baclight Ptoblem.

    hi guys i have had this sharp lc-40sh340k laying around for a while now. when you switch it on it goes on displays picture and light on screen but after 2 seconds the backlights switch off. i have tried different PSUs and same issue, also purchased a used inverter board on ebay for this tv and same issue. could it be the mainboard or even possible one of the CCFL tubes itself possibly breaking the circuit and shutting down the inverter ?

    any help would be great thanks
    Tags: None
    • nomoresonys
      Badcaps Legend
      • Jan 2013
      • 12331
      • U.S.
      #2
      Re: sharp lc-40sh340k Baclight Ptoblem.

      did you check all the fuses?

        Comment

        • nomoresonys
          Badcaps Legend
          • Jan 2013
          • 12331
          • U.S.
          #3
          Re: sharp lc-40sh340k Baclight Ptoblem.

          2 seconds to black seems like a capacitor issue?

            Comment

            • Mikeyboy2007
              Badcaps Veteran
              • Mar 2013
              • 745
              • Scotland
              #4
              Re: sharp lc-40sh340k Baclight Ptoblem.

              nomoresonys i already replaced psu with a known working one and what fuses will i check ? would it be a fuse though if the backlight is going on for even 2 seconds ?

                Comment

                • nomoresonys
                  Badcaps Legend
                  • Jan 2013
                  • 12331
                  • U.S.
                  #5
                  Re: sharp lc-40sh340k Baclight Ptoblem.

                  post some good clear pics., of all the boards and one of the whole back and how theyre connected, a pic. is worth a thousand words.

                    Comment

                    • nomoresonys
                      Badcaps Legend
                      • Jan 2013
                      • 12331
                      • U.S.
                      #6
                      Re: sharp lc-40sh340k Baclight Ptoblem.

                      you might have gotten a bad inverter from ebay, it may be a lamp issue.

                        Comment

                        • nomoresonys
                          Badcaps Legend
                          • Jan 2013
                          • 12331
                          • U.S.
                          #7
                          Re: sharp lc-40sh340k Baclight Ptoblem.

                          did you grab a service manual?

                            Comment

                            • nomoresonys
                              Badcaps Legend
                              • Jan 2013
                              • 12331
                              • U.S.
                              #8
                              Re: sharp lc-40sh340k Baclight Ptoblem.

                              http://www.toms-service-manuals.com/...h=Submit+Query this should help, pretty good info on troubleshooting.
                              Last edited by nomoresonys; 12-28-2014, 01:27 PM.

                                Comment

                                • Mikeyboy2007
                                  Badcaps Veteran
                                  • Mar 2013
                                  • 745
                                  • Scotland
                                  #9
                                  Re: sharp lc-40sh340k Baclight Ptoblem.

                                  are these any helpfull ? and not sure what im looking for in the service manual ?
                                  Attached Files

                                  if you find these attachements useful please consider making a small donation to the site

                                    Comment

                                    • budm
                                      Badcaps Legend
                                      • Feb 2010
                                      • 40746
                                      • USA
                                      #10
                                      Re: sharp lc-40sh340k Baclight Ptoblem.

                                      It will only take one bad lamp to cause the inverter to shutdown.
                                      You can first verify that the 24VDC is still present on the inverter board and also the bl_on is also present.
                                      Some time you can bypass the detection time out on the PWM IC of the inverter circuit but you will need to get the spec of the IC.
                                      You may have to take the panel apart to inspect the lamp but it is delicate works.
                                      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

                                        • Mikeyboy2007
                                          Badcaps Veteran
                                          • Mar 2013
                                          • 745
                                          • Scotland
                                          #11
                                          Re: sharp lc-40sh340k Baclight Ptoblem.

                                          ive taken a few samsung panels apart to change CCFL tubes. i will check 24v and BL_ON and get back to you thanks

                                            Comment

                                            Previous template Next

                                            Related Topics

                                            Collapse
                                            • JFarm
                                              Sharp Aquos LC-46E77UN inverter testing
                                              by JFarm
                                              I picked this TV out of a trash pile. When I plug it in I can hear the relay on the power supply “click” almost immediately, and then 7 seconds later there is another “click” and the power/OPC LEDs start to flash: two pulses on the power LED, one on the OPC LED. I didn't notice any sign of life from the backlight, but more on that below.....

                                              The service manual () says this is a “DET_10V error: UR10V or A9V is not applied”, but after checking several voltages I believe the power unit is tripping off due to an overload as soon as the backlight tries to come on; this kills...
                                              03-21-2021, 11:10 AM
                                            • organman
                                              Sharp LC-60LE633U Inverter output voltages
                                              by organman
                                              Greetings, I have a Sharp LC-60LE633U when powered up only the V light comes on. I have checked the LED strips and they all light up. When the LED's are plugged into the PS board I get an output voltage of 74v DC. If I unplug the LED's the output voltage on the PS is 184v DC. Does this indicate a weak PS?
                                              Thanks...
                                              03-22-2023, 06:47 PM
                                            • eccerr0r
                                              inverter H tree driver imbalance in an AC inverter
                                              by eccerr0r
                                              My cheap crappy 1KW grid tie inverter (GTI) seems to keep blowing IGBTs. When I first got it, it had two failed IGBTs. It used four 60N100's (TO264). I bought 5 from a dubious source (fleabay) and replaced just the two that were dead. The GTI worked for almost two years but recently one of the two that I replaced failed. Since I had three spares, I replaced the dead one. Then a few weeks later it failed again. Weird. Well since I bought dubious China-sourced IGBTs from fleabay it could very well just be a mixture of fakes. I replaced it, but then a day later it failed again! I put in the last...
                                              11-16-2025, 12:34 PM
                                            • organman
                                              Sharp LV-60LE633U inverter output voltages
                                              by organman
                                              Greetings, I have a Sharp LC-60LE633U when powered up only the V light comes on. I have checked the LED strips and they all light up. When the LED's are plugged into the PS board I get an output voltage of 74v DC. If I unplug the LED's the output voltage on the PS is 184v DC. Does this indicate a weak PS?
                                              Thanks
                                              03-13-2023, 06:48 PM
                                            • x_orange90_x
                                              Vizio E55-E1 bad backlights or bad inverter?
                                              by x_orange90_x
                                              I just got this tv today and it appeared to have no backlight on. After taking off the rear cover and checking again in the dark I can see that MAYBE one quadrant is lit.. But still it's quite dim. I was going to check the LEDs with my tester, and I found LED 1 and LED 2 + pins on the wire from the inverter, but I couldn't identify a ground. Nonetheless I tried using a mounting screw on the inverter board and also the chassis as ground but regardless my tester reads 300 which is what it reads when there is no voltage draw.

                                              I don't know how exactly to test the inverter itself. Is it...
                                              01-29-2025, 09:24 PM
                                            • Loading...
                                            • No more items.
                                            Working...