LCD Samsung LE40B651 start loop

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • cristi16707
    New Member
    • Dec 2015
    • 6
    • Romania
    #1

    LCD Samsung LE40B651 start loop

    I have an issue with my Samsung LE40B651 LCD, and I need your help.
    Few weeks ago, when I tryed to power on from stdy,I got it in totaly blank status: no stdy LED, no sound, no backlight. Thanks to your help indication (especialy budm and tom66) I was able to fix power supply board (BN44-00264A) by replacing of UM801S(STRW6252).
    Now I have 5.3V, 13V on CNM802, CP815~390VDC,I get stdby LED, I can power on from sdtby, I get starting sound, I get backlight, but not any image. After around 5 seconds it reboot again, and again .. and so on. For more details about simptoms, please follow below video :
    https://www.youtube.com/watch?v=ufYw...ature=youtu.be

    If I pull out connector between power supply and main board, I get a stable backlight status.
    If I pull out connector between main board and Tcon, the start-up loop is still there.

    Could you give me some advices, please ? Can be a main board issue (BN40-00145A) ?
    Last edited by cristi16707; 12-15-2015, 07:00 AM.
    Tags: None
    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA
      #2
      Re: LCD Samsung LE40B651 start loop

      It does sound like you have main board problem since you are getting the backlights when the cable between the main board and the power supply board is disconnected.
      BTW, what happen if you disconnect the cable between the remote IR and the key panel button board?
      Try heating the main board with hair dryer for a few minutes to see if the symptom changes.
      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

        • cristi16707
          New Member
          • Dec 2015
          • 6
          • Romania
          #3
          Re: LCD Samsung LE40B651 start loop

          I suppose you referred to cable from attached picture. When I disconnected, nothing happen, as the TV is in stdby, but cannot power on it.
          I tried to heat the mainboard for a few minutes but not any change.
          New idea ?
          Attached Files

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA
              #4
              Re: LCD Samsung LE40B651 start loop

              Originally posted by cristi16707
              I suppose you referred to cable from attached picture. When I disconnected, nothing happen, as the TV is in stdby, but cannot power on it.
              I tried to heat the mainboard for a few minutes but not any change.
              New idea ?
              Forget to tell you to turn the TV on first then disconnect the cable, if it still does the same thing and heating the board does not make the difference, then just need to get the new working main 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

                • cristi16707
                  New Member
                  • Dec 2015
                  • 6
                  • Romania
                  #5
                  Re: LCD Samsung LE40B651 start loop

                  I disconnected IR cable, after power on, but still the same result.
                  Then I "cooked" the board but with not any result. I tried again to disconnect IR, but the same. It seems that I have bad lucky !
                  Are you sure that main board is issued ? Do you know some equivalent boards for BN40-00145A ?

                    Comment

                    • johnboy1313
                      Badcaps Legend
                      • Nov 2012
                      • 1959
                      • USA
                      #6
                      Re: LCD Samsung LE40B651 start loop

                      Originally posted by cristi16707
                      I disconnected IR cable, after power on, but still the same result.
                      Then I "cooked" the board but with not any result. I tried again to disconnect IR, but the same. It seems that I have bad lucky !
                      Are you sure that main board is issued ? Do you know some equivalent boards for BN40-00145A ?
                      BN40-0145A is the tuner part number. The main board should start with BN94. It looks like your board is actually BN94-02583U.

                        Comment

                        • cristi16707
                          New Member
                          • Dec 2015
                          • 6
                          • Romania
                          #7
                          Re: LCD Samsung LE40B651 start loop

                          Yes, you are right. I attached tuner picture.
                          As not any new idea, I'm looking for such kind of board. I keep you post about result.
                          Thank you for your support !
                          Attached Files

                            Comment

                            • cristi16707
                              New Member
                              • Dec 2015
                              • 6
                              • Romania
                              #8
                              Re: LCD Samsung LE40B651 start loop

                              After main board replacement TV works fine.
                              Many thanks to budm !

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA
                                  #9
                                  Re: LCD Samsung LE40B651 start loop

                                  Thanks for the follow-up on the repair.
                                  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

                                    Previous template Next

                                    Related Topics

                                    Collapse
                                    • Asraf Atb
                                      Help Needed: Samsung UE55MU8000 Dead - Possible Main Board Issue
                                      by Asraf Atb
                                      Hi everyone,

                                      Im looking for some advice regarding my Samsung UE55MU8000 TV with main board model BN94-11606C. The TV suddenly stopped turning on and now shows no signs of life at all not even the standby light at the bottom.

                                      Initially, I suspected an issue with the PSU, so I took it to a repair center. They tested it and confirmed that the PSU works perfectly, even on other TVs. Based on that, I started investigating the main board.

                                      I disconnected the main board from the PSU, and the backlight turned on, which seems to confirm the main board is the issue....
                                      1 Photo
                                      01-27-2025, 05:02 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...
                                      5 Photos
                                      10-28-2024, 05:06 PM
                                    • Lee M.
                                      Samsung UN75RU8000FXZA bad main board?
                                      by Lee M.
                                      When plugged in it will click and cycle the BL on and off, no pic and does not respond to remote. When I disconnect the cable from the PS board to the main board and then plug it in the BL will come on and stay on. There are only two boards in this set, the LVDS cables from the panel driver boards connect directly to the main board. Since the BL comes on and stays on I'm thinking the PS board is ok and the problem is on the main board. Should I order another main board or do I need to do more testing? thanks, Lee
                                      11-08-2023, 07:46 PM
                                    • jb_Bak
                                      Sony xbr-65x900c main board issues?
                                      by jb_Bak
                                      Hey guys great forum glad to have found it. I bought a Sony XBR 65X900C cheaply because it didn't work. No signs of life at all not even a light/led. All I hear is a brief high voltage sound when I throw the power to it.

                                      Didn't see any obvious signs of damage so right away started checking voltages. This is what I see:
                                      Power Board Connector that goes to Main board
                                      CN6401
                                      Pin 01 NC
                                      Pin 02 NC
                                      Pin 03 "BL_ON": 0V
                                      Pin 04 "N/C"
                                      Pin 05 "STBY 3.3V": 3.5V
                                      Pin 06 "GND": N/C
                                      Pin 07 "AC_OFF"...
                                      09-27-2021, 04:52 PM
                                    • JDC
                                      (SOLVED) - ONN 100012588 No Power, Then Rebooting After Main Board Change
                                      by JDC
                                      ONN 100012588
                                      Issue: No Power, Then Rebooting After Main Board Change

                                      Short answer: replace main board and power board
                                      Technical answer: replace main board and Q306 & Q307 on power board.

                                      Long answer:

                                      TV wouldn't turn on. Power switch was fine which means the main board isn't processing the power on signal. Replaced main board. TV turns on now but randomly reboots. Bad main board? EEPROM? Tried to pull main board and got a shock touching the corner of the board. That's weird. C334 (450V 10uf) capacitor is still holding a high charge....
                                      07-15-2022, 07:39 AM
                                    • Loading...
                                    • No more items.
                                    Working...