Seiki TV - No Backlight

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • daveytee999
    New Member
    • Sep 2021
    • 5
    • United Kingdom

    #1

    Seiki TV - No Backlight

    Think I'm jinxed - since I joined this forum another TV of mine has gone kaputt!

    It's a Seiki - no backlight. Screen is on and works (can see when shining a torch on it).
    Have had the Tv apart and not sure I understand the voltages I'm getting - when tv in standby getting 35 volts DC on the 2 connectors that go to the back light which doesn't make sense to me. When TV switched on it goes up to between 48 and 58 volts.
    All caps and other components look normal, all diodes seem to check out, not tested the caps 'cos I think I have to take them off the pcb to test (is that right?)
    What I don't understand is why both backlights would fail at the same time (as there's 2 connectors) - I guess they are wired in series which explains the high voltages but for both sets to go at the same time seems strange.
    Can take the whole thing apart and get to the led strips if necessary but wanted confirmation that it's highly likely to be the strips that are at fault first.
    Is there a resistance test I can do on the connectors to test this?

    TIA.
  • neilc6
    Badcaps Legend
    • Nov 2015
    • 1550
    • Canada

    #2
    Re: Seiki TV - No Backlight

    Backlight issues are almost always the backlights themselves. Very difficult to find new strips for these white label models like RCA.

    https://techhometravel.com/lg-ln-ser...ed-backlights/

    Comment

    • SMDFlea
      Super Moderator
      • Jan 2018
      • 20613
      • UK

      #3
      Re: Seiki TV - No Backlight

      Originally posted by daveytee999
      Think I'm jinxed - since I joined this forum another TV of mine has gone kaputt!
      Post the model number please

      https://www.badcaps.net/forum/showthread.php?t=24661
      All donations to badcaps are welcome, click on this link to donate. Thanks to all supporters

      Comment

      Related Topics

      Collapse

      • Tynan Dill
        Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
        by Tynan Dill
        I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

        Upon bringing it home and plugging it up, it showed a standby light.

        I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

        The screen seems to blackout and stay black, but with a flashlight I can see the display.

        With my Playstation 4 connected via HDMI, and running a game I can hear sound.

        Assuming...
        11-22-2024, 01:46 PM
      • triplefour
        UN65TU700DF picture and sound but no backlight. BL tests ok but repl. PSU didnt fix!
        by triplefour
        this tv is throwing me for a loop. do samsung tvs no longer have the backlight self test feature built into the power supply?
        i tested the backlight with my LED tester and it lights up both strips. one of them reads 100v and the other reads 63.7v.
        unplugged mainboard from power supply but left backlight plugged in, and then plugged psu wall power in. expected to see backlights light up but see nothing.
        according to how ive diagnosed in the past, this would almost always be a bad power supply. replacement power supply was cheap like 20$ from ebay. but still i get not even...
        09-13-2023, 10:43 PM
      • Yanleb
        Vizio M70-D3 4K with dark spots backlight issue
        by Yanleb
        I have a Vizio M70-D3 4K with a dark spots backlight issue. It is using the Y8387248A backlight driver board.

        On this model each of the 64 transistor powers 2 LEDs. Using my TKDMR TD3H backlight tester I've determined that the backlight LED strips were the issue, and the backlight driver board was just fine. Some LED pairs required 5.9 volt at 155mA, some required 9.5 volt and some were completely open.

        I've removed the LCD panel and once the LED strips were exposed I've tested them again by connecting my LED tester directly on the test pads. To my surprise all, I've...
        03-22-2022, 01:06 AM
      • DanPoka
        Guide me through repairing a Dell p2210f LCD ccfl backlight monitor
        by DanPoka
        I bought this p2210f dell monitor to fix. Schematic is the same as p2210.
        Behaviour is that monitors comes on but then backlight switches off almost instantly. If I look with flashlight I can still find the "No signal message". So definitely a backlight issue. Trying to advance the issue I proved that the protection circuit is switching off the backlight by shorting out C3 and resistor to disable the INL chip then re enable by removing the short.
        This is where it gets interesting. When I disassembled the monitor to solder leads on c3 capacitor I noticed the backlight flickered...
        02-15-2025, 05:05 AM
      • Comp_Pro
        No Backlight Macbook A1990 820-01041
        by Comp_Pro
        Hello all,

        Am trying to figure out this backlight issue with this A1990 Macbook Pro.

        Tests performed:

        There is no backlight even with a good screen.
        Backlight IC is receiving the correct support voltages.
        Fuse F8400 ok
        Current sense resistor R8400 ok
        Backlight IC is receiving 3.3V on enable pin.
        Backlight IC receiving voltage from PPBUS_G3H, aprox 12.5V.
        Backlight IC receiving 5V from PP5V_G3S
        Backlight IC BKLT_SCL and BKLT_SDA both measure 0.545V diode mode to ground
        I2C_BKLT_SCL and I2C_BKLT_SDA both measure...
        05-06-2024, 10:23 PM
      • Loading...
      • No more items.
      Working...