Hisense 40K360MN dim picture like in power saving mode

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  • nortnil
    Member
    • Jul 2008
    • 40

    #1

    Hisense 40K360MN dim picture like in power saving mode

    Hisene 40k360MN.

    I am getting a dim picture. The TV will boot, and the panel will be full brightness for a split second before going dim. It is like it is in a power saving mode (picture below). I have seen the panel kick on all the way for a minute or two so I am guessing it is a power issue either from not enough power or something telling it to go into a power saving mode.

    I have factory reset the TV, and adjusted all of the settings in the menu to see if something was a problem there. No luck on that end.

    I did see a pin labeled "dimming in the power cord coming from the power supply to the main board. It is giving about 5.40v when powered on.

    Visually I don't see any caps that look bad or any scorching on the power supply or the main board.

    Below is a picture of the dim display and what the TV looks like with the back removed.

    If anyone has any advice of what to try next, I would definitely appreciate it.













    If you need better angles or close ups of certain areas let me know. Thank you.
    Attached Files
    Last edited by nortnil; 03-03-2015, 06:49 PM. Reason: added close ups of power supply and main board
  • CapLeaker
    Leaking Member
    • Dec 2014
    • 8030
    • Canada

    #2
    Re: Hisense 40K360MN dim picture like in power saving mode

    So you are saying the backlight brightness is going low? What happens if you take the dimming pin out of the plug? TV should run on full backlight then. Another thought... did you do a factory default on the set yet?
    Last edited by CapLeaker; 03-03-2015, 08:13 PM.

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #3
      Re: Hisense 40K360MN dim picture like in power saving mode

      Can you put the list of the pin names of those connector?
      "I did see a pin labeled "dimming in the power cord coming from the power supply to the main board. It is giving about 5.40v when powered on." Did it go down after that or it stays at 5.40V? BTW, please check you meter's batteries, they may be low so it shows the reading higher than what it should be, the dimming max is 5V (5V = MAX brightness).
      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

      • nortnil
        Member
        • Jul 2008
        • 40

        #4
        Re: Hisense 40K360MN dim picture like in power saving mode

        Originally posted by CapLeaker
        So you are saying the backlight brightness is going low? What happens if you take the dimming pin out of the plug? TV should run on full backlight then. Another thought... did you do a factory default on the set yet?
        Yes, when the TV turns on for a split second it is at full brightness. Then the backlight drops down like it is in sleep mode. When I go to the image settings turning brightness and backlight all the way up do nothing.

        The top right of the screen is also very dark. It looks like that LED is out entirely.

        I just tried disconnecting the dimming pin and no picture would display.
        Last edited by nortnil; 03-03-2015, 09:10 PM.

        Comment

        • CapLeaker
          Leaking Member
          • Dec 2014
          • 8030
          • Canada

          #5
          Re: Hisense 40K360MN dim picture like in power saving mode

          Ok... can you measure voltages on all the pins on the power supply with name of the pins beside it and post it?

          Comment

          • nortnil
            Member
            • Jul 2008
            • 40

            #6
            Re: Hisense 40K360MN dim picture like in power saving mode

            Originally posted by budm
            Can you put the list of the pin names of those connector?
            "I did see a pin labeled "dimming in the power cord coming from the power supply to the main board. It is giving about 5.40v when powered on." Did it go down after that or it stays at 5.40V? BTW, please check you meter's batteries, they may be low so it shows the reading higher than what it should be, the dimming max is 5V (5V = MAX brightness).
            You are right on the batteries. I will have to get a new one and post back with an update. In the meantime below are close ups of the connectors.

            Power supply side


            Main board side


            I don't know if you need to know what cable matches what pin on each side, but just in case:
            Power Supply to Logic Board
            STB - Purple - On/Off
            12V - Blue - Left 12VS
            12V - Green - Right 12VS
            SW - Yellow - BL
            PWM - Orange - Dimming
            GND - Red - Left GND
            GND - Brown - Right GND

            The last GND and the two 14V pins on the logic board are blank.

            Originally posted by CapLeaker
            Ok... can you measure voltages on all the pins on the power supply with name of the pins beside it and post it?
            I will have to get back to you on this tomorrow when I get a new battery for my volt meter.
            Attached Files
            Last edited by nortnil; 03-03-2015, 08:57 PM.

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: Hisense 40K360MN dim picture like in power saving mode

              "PWM - Orange - Dimming" OK it uses PWM dimming signal (10% pulse width = min brightness, 90% pulse width = max brightness), it is not using variable DC Analog dimming signal 0~5VDC.
              If you check with DC meter and the pulse width is at 50%, then the meter should show 2.5V (50% of 5V).
              So you need to check again what you have at that pin, if you remove that PWM dimming wire then then you should see full brightness.
              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

              • nortnil
                Member
                • Jul 2008
                • 40

                #8
                Re: Hisense 40K360MN dim picture like in power saving mode

                Originally posted by budm
                "PWM - Orange - Dimming" OK it uses PWM dimming signal (10% pulse width = min brightness, 90% pulse width = max brightness), it is not using variable DC Analog dimming signal 0~5VDC.
                If you check with DC meter and the pulse width is at 50%, then the meter should show 2.5V (50% of 5V).
                So you need to check again what you have at that pin, if you remove that PWM dimming wire then then you should see full brightness.
                I just replaced the battery in my meter and rechecked the voltages:
                STB 4.96V
                12V 12.08V
                12V 12.08V
                SW 3.37V
                PWM 3.96

                When I disconnect the PWM cable from the molex connect and power on the TV, I don't get any backlight at all.

                There is also another cable coming off of the power supply going into the LCD panel frame. Does this have anything to do with the backlight?

                Pins are labeled (voltages to the right):
                V1P 0V
                V1N -2.06V
                V2P -2.06V
                V2N 0V

                Picture of the second connector to the right of the main connector:
                Attached Files
                Last edited by nortnil; 03-04-2015, 05:22 PM.

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #9
                  Re: Hisense 40K360MN dim picture like in power saving mode

                  "There is also another cable coming off of the power supply going into the LCD panel frame. Does this have anything to do with the backlight?

                  Pins are labeled (voltages to the right):
                  V1P 0V
                  V1N -2.06V
                  V2P -2.06V
                  V2N 0V"
                  That connector (with BLUE, BLACK, RED, AND WHITE) is for the LED strings inside the panel.
                  Are the Voltage readings on those using chassis as the GND ref for the meter/ If it is, the LED driver Voltage booster circuit is not working.
                  If it is working you should see >100VDC (measured right at the two legs of the caps) on filter caps C869, 859, 853, 909.
                  So see if the Voltage does jump up high when power switch is activated and stays high or if it jumps up high and then drops down.
                  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

                  • nortnil
                    Member
                    • Jul 2008
                    • 40

                    #10
                    Re: Hisense 40K360MN dim picture like in power saving mode

                    Originally posted by budm
                    That connector (with BLUE, BLACK, RED, AND WHITE) is for the LED strings inside the panel.
                    Are the Voltage readings on those using chassis as the GND ref for the meter/ If it is, the LED driver Voltage booster circuit is not working.
                    If it is working you should see >100VDC (measured right at the two legs of the caps) on filter caps C869, 859, 853, 909.
                    So see if the Voltage does jump up high when power switch is activated and stays high or if it jumps up high and then drops down.
                    Thank you for being so helpful.

                    I made a mistake with my meter and gave you bad information on the LED string connector. I didn't realize the power coming out was so high, and I had my meter set too low causing erroneous readings.

                    After correcting that I get these readings using the chassis as the GND
                    V1P 324VCD
                    V1N 0VCD
                    V2P 0VCD
                    V2N -139VCD

                    Do those look closer to where they should be?

                    As far as the caps the Voltage does jump high when power is activated and stay high.

                    I measured all of them using chassis as GND and then again across the pins themselves. All of them had the same value using chassis as GND and the negative lead as GND except for C869. It gave me 0VCD when using the chassis as GND

                    C896 138VCD (0VCD when using chassis)
                    C859 163VCD
                    C853 163VCD
                    C909 324VCD

                    I am still pretty green when it comes to taking readings and troubleshooting. If I am using the wrong terms or it sounds like I am doing something wrong, please let me know what I need to do to get you the right information.

                    Thanks again
                    Last edited by nortnil; 03-04-2015, 06:50 PM.

                    Comment

                    • nortnil
                      Member
                      • Jul 2008
                      • 40

                      #11
                      Re: Hisense 40K360MN dim picture like in power saving mode

                      I forgot to mention that during the power on for the split second the backlight is at full brightness C869, 859, and 853 all dropped to around 140VCD. I didn't notice a change on C909.

                      Comment

                      • budm
                        Badcaps Legend
                        • Feb 2010
                        • 40746
                        • USA

                        #12
                        Re: Hisense 40K360MN dim picture like in power saving mode

                        "C909 324VCD" That indicating you have open connection or LED/s in the string.
                        Similar problem to this one:
                        https://www.badcaps.net/forum/showthread.php?t=44541
                        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

                        • nortnil
                          Member
                          • Jul 2008
                          • 40

                          #13
                          Re: Hisense 40K360MN dim picture like in power saving mode

                          Okay so that means it shouldn't be anything on the power supply then? I take it my next step is to try to disassemble the panel itself and see if there is anything I can do on the LED string?

                          Comment

                          • budm
                            Badcaps Legend
                            • Feb 2010
                            • 40746
                            • USA

                            #14
                            Re: Hisense 40K360MN dim picture like in power saving mode

                            Originally posted by nortnil
                            Okay so that means it shouldn't be anything on the power supply then? I take it my next step is to try to disassemble the panel itself and see if there is anything I can do on the LED string?
                            Correct. Can you also post good clear the pictures of the bottom side of the board for me? I would like to see if the LED strings are connected in series or it has power supply per string.
                            The hard part will taking the panel apart without damaging the LCD Glass panel.
                            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

                            • nortnil
                              Member
                              • Jul 2008
                              • 40

                              #15
                              Re: Hisense 40K360MN dim picture like in power saving mode

                              Will the 4th picture in my 1st post work? When you open it in a new window and zoom in it is pretty high resolution. If there is a certain area you need me to focus on I can try to get you isolated pictures tomorrow.

                              Or did you mean of the LED board when I get the panel open?

                              Comment

                              • nortnil
                                Member
                                • Jul 2008
                                • 40

                                #16
                                Re: Hisense 40K360MN dim picture like in power saving mode

                                Deleted - duplicate
                                Last edited by nortnil; 03-04-2015, 10:48 PM.

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA

                                  #17
                                  Re: Hisense 40K360MN dim picture like in power saving mode

                                  Bigger pictures (bottom side) of that area of the connector with RED/BLACK/BLUE/WHITE for the LED strings.
                                  Last edited by budm; 03-05-2015, 12:57 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

                                  • nortnil
                                    Member
                                    • Jul 2008
                                    • 40

                                    #18
                                    Re: Hisense 40K360MN dim picture like in power saving mode

                                    Will this picture work?

                                    That was the closest I could get for everything to still be in focus. If you need something closer I can try to take segments and stitch them together for you. Just let me know.

                                    I was also wondering about C869 having 0VCD when I measured using the chassis as ground. Is that normal, or could it indicate there is a fault breaking it's connection to ground?
                                    Attached Files

                                    Comment

                                    • budm
                                      Badcaps Legend
                                      • Feb 2010
                                      • 40746
                                      • USA

                                      #19
                                      Re: Hisense 40K360MN dim picture like in power saving mode

                                      " I was also wondering about C869 having 0VCD when I measured using the chassis as ground. Is that normal, or could it indicate there is a fault breaking it's connection to ground?" That is why I need really good pictures to trace out the connections.
                                      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

                                      • nortnil
                                        Member
                                        • Jul 2008
                                        • 40

                                        #20
                                        Re: Hisense 40K360MN dim picture like in power saving mode

                                        Does that one work? It is 50 inches across at full resolution.

                                        Comment

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