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Vizio E500i-A0 backlight on 1/2 second off 2 seconds

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    #1

    Vizio E500i-A0 backlight on 1/2 second off 2 seconds

    My Vizio E500i-A0 TV has a power supply fluctuating an output of 124VDC-129VDC to the back lights (LEDs 1 and LEDs 2) with or without the back lights connected to the power supply/driver unit (0500-061400280) output.
    I do not see a working standby light on the TV(do not know where to test for it's power)
    The blue indicator light comes on when the TV is powered on and fades to off after a second or two. The TV has audio, the picuture/etc will flash on for about 1/2 second then go black for 2 seconds.
    The panel display is by LG [LC500DUG-(JF)(R1)]
    The main board is LAQKNTBP3500360
    No apparent burnout/etc on either board.
    I cannot identify the voltage regulators on the boards
    I have a current limiting power supply (max output 50VDC/2A) and wonder if I can test LED strings 1 and 2 separately.
    Need a schematic/diagram for the boards and your advice.
    I am thinking I should change both boards but need to test the backlights to verify they all work without complete disassembly if possible.
    Tags: None
    #2
    Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

    Need some pictures of boards. I don't think you have enough voltage to check led's
    I assume no responsibility for any stupid suggestions I might post.

    Comment

      #3
      Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

      Here's a shopjimmy test leds for your set.

      https://www.youtube.com/watch?v=UxR8-xztdGs
      Willing to help but I'm no expert.

      Comment

        #4
        Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

        Trying to figure out how to upload a pic. Hope this works...

        Comment

          #5
          Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

          Okay I'll attempt this again. Pics were took with my phone...may need to get my camera out and figure how to get the pic to my laptop.. Real new at this upload stuff.
          Attached Files
          Last edited by j0etee1; 03-03-2017, 12:47 PM.

          Comment

            #6
            Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

            Originally posted by dick_barton View Post
            Here's a shopjimmy test leds for your set.

            https://www.youtube.com/watch?v=UxR8-xztdGs
            great video.. Thanks

            Comment

              #7
              Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

              here are possibly better pic of the boards. Can anyone assit me?
              powerboard is 0500-0614-0280
              main board is 3650-0112-0150
              serial number is LAQKNTBP3500360
              panel display is by LG LC500DUG-(JF) (R1)
              TV Model is E500i-A0
              got sound and got pic when back light LEDs flash on
              back light LEDs FLASH on 1/2 second off 2 seconds then repeats
              no standby led
              blue LED comes on when powered then fades out in a second
              124VDC-129VDC fluctuating voltage at output to LEDs connected or disconnected.
              Attached Files

              Comment

                #8
                Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                1) There is no standby LED on this series of TVs.

                2) I believe that you have a bad LED in your backlight and the TV takes its time to flag the error. What happens after the 2 second black period?

                Comment

                  #9
                  Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                  The on 1/2 second and off 2 second sequence repeats over and over. What concerns me is that the output VDC to the LED backlights fluctuates from 124-129 VDC with or without the LEds being connected to the PSU.

                  Comment

                    #10
                    Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                    Originally posted by SLK001 View Post
                    1) There is no standby LED on this series of TVs.

                    2) I believe that you have a bad LED in your backlight and the TV takes its time to flag the error. What happens after the 2 second black period?
                    ShopJimmy has an LED test set avaiable. Do you think it will test the LED strings without total disassembly?

                    Comment

                      #11
                      Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                      I have led tester. Very handy. It will test one at a time or whole string.
                      I assume no responsibility for any stupid suggestions I might post.

                      Comment

                        #12
                        Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                        Originally posted by j0etee1 View Post
                        ShopJimmy has an LED test set avaiable. Do you think it will test the LED strings without total disassembly?
                        There are LED testers out there, but I don't know anything about the SJ model. They should run around $50.

                        Comment

                          #13
                          Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                          Got my tester on ebay for $36. Real happy with it.
                          I assume no responsibility for any stupid suggestions I might post.

                          Comment

                            #14
                            Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                            Thanks so much to all responders. I just ordered an LED tester.. expect to receive it around the tenth of March. I m thinking the comment about an led being out is the issue; however, I do not want to attempt to tear down the panel until I know for certain.

                            Comment

                              #15
                              Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                              when using LED tester to check each LED string you should observe the Voltage reading since LED with shorted out one or more LED will still light up.
                              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

                                #16
                                Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                                Originally posted by budm View Post
                                when using LED tester to check each LED string you should observe the Voltage reading since LED with shorted out one or more LED will still light up.

                                I certainly will do that.. by the way..you have an impressive collection of pics and info on your link.

                                Thanks for the feedback

                                Comment

                                  #17
                                  Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                                  Hello techs
                                  Today,I received the back-light/LED tester(model GJ2C). With the back-light strings one and two disconnected from the PSU/Driver board and the TV on I can see the menu on the screen with each string tested independent of the other.. LED string one stabilizes at 95.6 volts as does LED string two; although it takes a minute or less. With the test set removed and LED strings plugged into the PSU/Driver board I see fluctuating 124-129 VDC and when the LED strings unplugged I see the same fluctuating 124-129 VDC. I know that the LED strings consist of 30 beads each with three LEDs in a string (if they are actually as seen on ebay/etc). Think it is the driver board section? Maybe a cap or two? please advise... hope I don't have to disassemble the display.

                                  Comment

                                    #18
                                    Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                                    There is further information at the following thread.

                                    https://www.badcaps.net/forum/showth...light=E500i-A0

                                    I'm thinking that with the tester showing that the second string of leds light up slowly compared to the first string may well be indicating there is a problem with one of those leds in that string. It hasn't failed completely but I suspect since it's taking longer than it should to light (and therefore the current to pass through the string) the protection circuit may be taking over. Just a thought.

                                    Can you reduce the backlight to minimum and see if the leds stay on.
                                    Willing to help but I'm no expert.

                                    Comment

                                      #19
                                      Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                                      The LEDS on both strings take about the same amount of time to stabilize to the 95.6 volts. The user manual of the tester purchased indicates that the voltage will gradually rise until it stabilizes. The second test with the tester took about 3 to 5 seconds to stabilize on both strings at 95.6 vdc. (95.6 vdc\30 beads = 3.187 vdc/bead and 3.187vdc/3 leds/bead =1.062volts per LED. Does that figure correctly? I do not know what type of LED is used in the Back Light strings

                                      If I recall correctly, there was about a 0.6vdc drop on the LEDs we used in electronic labs with 1 milli amp to keep them on. As all can tell I'm reluctant to attempt disassembly of a 50 inch display - having never done it before. I'm tempted to purchase a PSU/LED driver board; but, after reading the Link you sent and noting that the output voltage was fluctuating on his board too, I'm confused. I did not see a response that informed on what the member did to resolve the issue... b/light strings or psu/driver board replacement.

                                      Comment

                                        #20
                                        Re: Vizio E500i-A0 backlight on 1/2 second off 2 seconds

                                        The trouble is that thread never got updated so we dont know what the fix was but a quick read of the voltages he posted it does look like led issue on his set your leds are the same voltage and take roughly as you say time to stabailize if this was my set i would try another psu/led board first if it dose not solve the issue you can re sell it on. Taking a 50in lcd apart is going to be a risk i would rule a psu fault out first myself.

                                        Comment

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