TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • triplefour
    Badcaps Legend
    • May 2014
    • 1747
    • USA

    #1

    TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

    Blank Backlit Screen w/ sound verified via DVD on HDMi 3
    no change to display when disconnect tcon
    no change to display when disconnect panel cables (both sides, one at a time, etc-)
    can faintly see a vertical dividing line splitting the panel even in half. super faint tho.
    also can faintly see a black cloud in the center of the screen. a darker area.
    color of screen is backlit black screen which basically looks gray
    12v present at TCON fuse
    other voltages on LVDS cable (TCON side) are missing. only see 2 pins with voltage .69v and .60v
    values dont change when disconnecting panel cables or when there is no siganl present (unplug DVD from hdmi3)
    Standby light continually flashes in the pattern 2 quick flashes, 1 second pause, repeat
    tv has "speaking menus" enabled
    suspect MB for not sending voltage to LVDS cable but cant rule out panel defect as well.
    or maybe tv thinks im blind so why bother display picture???
    any help is much appreciated!
    thanks
    Attached Files
    Don't fear the repair...
  • triplefour
    Badcaps Legend
    • May 2014
    • 1747
    • USA

    #2
    Re: TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

    anyone have any tips? should i just assume the MB is bad since i dont see voltages (besides the 12v) going to TCON?
    Don't fear the repair...

    Comment

    • tmhobadcap
      Senior Member
      • Apr 2019
      • 146
      • CANADA

      #3
      Have you tried checking on the backlight leds?
      I have the same tv with a few leds failed. Then there is no picture on the screen but sound.

      Comment

      • tiki66
        Member
        • Jul 2016
        • 37
        • Croatia

        #4
        Originally posted by triplefour
        Re: TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

        anyone have any tips? should i just assume the MB is bad since i dont see voltages (besides the 12v) going to TCON?
        MB only sends 12V to t-con and then t-con "creates" other voltages. Check for HAVDD, AVDD, VGL, VGH and other voltages on t-con, first with one side of screen connected then with other side of the screen connected. Are there any?

        Comment

        Related Topics

        Collapse

        • Ryan.man
          Macbook 2017 with touchbar (A1706) won't turn on after removing the screen
          by Ryan.man
          Hello everybody! Posting this in hopes somebody has some expertise that leads to a clear path of troubleshooting that saves me a lot of time!

          My macbook has the flex cable problem, the one that prevents the screen turning on. Ive been dealing with this for the last 3 years. Last year it went dead and I managed to fix it following youtube tutorials. But my fix wasnt the best, the problem returned a month later. This week, it went dead again. I again tried to fix it.

          This time the original cable broke too close to the screen, it can't be fixed without tearing the screen...
          02-04-2025, 12:23 PM
        • triplefour
          General question about LVDS voltages. Blank Backlit Screen.
          by triplefour
          im trying to understand how mainboards send data to tcons and tcons send data to panel boards and how panel boards control the panel itself.

          but starting at the beginning: if i have a tv with symptom: blank backlit screen, i want to verify if the mainboard is functioning properly first. its easy to see if its sending 12v to the tcon...but im pretty foggy on what the other lines of the LVDS connector should have on them.
          and also should they have the same voltages on them regardless of if the t-con is connected?
          and also how do you probe these pins easily? they are...
          12-18-2022, 02:45 AM
        • Chrissygizmo
          Panasonic TX-48CX350B backlights but white screen , blank screen
          by Chrissygizmo
          Hi all, I’ve got a problem I hope someone can help me fixi.
          I have a Panasonic TX-48CX350B tv , it powers up ok but the screen is blank, the backlights are working, there’s nothing else though, no picture or sound. I’m not sure what the fault is called whether it’s BLANK/ BLACK/ or WHITE SCREEN I’ve actually came across this before on a similar tv but just ended up scrapping it, I will upload pictures of the boards etc , if anyone could help me I would really appreciate it...
          01-11-2025, 03:18 PM
        • Kalman27
          Lenovo IdeaPad Slim 5 14IAH8 - Type 83BF OLED Blank screen
          by Kalman27
          We have a Lenovo IdeaPad Slim 5 14IAH8 - Type 83BF for repair. The original issue the OLED screen is blank.

          We have replaced the OLED screen with the exact model, also we replaced the LCD cable, but no luck.

          I think there is something with the motherboard. I don't really have experience with OLED screens so far, so not sure how it should work. I have seen some laptop comes with a separate controller board, but this model does not.

          Also, there is an error in Windows device manager - This device cannot start (Code 10) - Intel(R) Serial IO I2C Host Controller...
          06-17-2025, 05:52 AM
        • Spoonicks
          ASUS VH238T blank screen with backlight
          by Spoonicks
          Hello,

          I am having a problem with a ASUS VH238T.
          The monitor started by just going blank, but the integrated speakers, and the backlight worked. The OSD didn't pop up, neither did the messages of DVI No Signal, nor the Asus logo.
          Turning off the monitor, and turning it back on made no difference. But leaving the monitor off for a few hours returned the monitor back to normal. The problem will eventually return after a couple of hours.

          Today, it started exhibiting another symptom: the display started showing a white image, that didn't take the whole screen....
          07-04-2023, 01:29 PM
        • Loading...
        • No more items.
        Working...