LED Strip test points and testing?

Collapse
X
Collapse
+ More Options
Posts
 
  • Time
  • Show
Clear All
new posts
  • lmcancu
    Senior Member
    • Oct 2009
    • 158

    #1

    LED Strip test points and testing?

    Hi is there a guide in this forum on how to test the LED backlight TV strips? I purchased an LED tester on amazon, but I am a bit confused on the test points and how to test the individual LEDs? I took apart a RCA 43" TV Rlded4331b. Please see attached pictures. I understand that all the LEDs are in series, but on these strips I don't see any individual test points for each LED? Any tips or guides?
    Thanks in advance
    Attached Files
  • howardc64
    Badcaps Veteran
    • Jun 2017
    • 548
    • United States

    #2
    Re: LED Strip test points and testing?

    The 2 copper colored prints on both side of each LED lens (eg D6+ and -) are probably the anode cathodes test points of the LED. Try red tester probe on D*+ and black test probe on -

    Comment

    • lmcancu
      Senior Member
      • Oct 2009
      • 158

      #3
      Re: LED Strip test points and testing?

      Yes that's true but its quite confusing. I did figure it out and will try to explain in the photos below. This is with an LED tester, but you can also use a voltmeter on diode setting for the single LEDs.
      Edit: Actually, you can test the left-most LED without removing the diffuser. Place the negative probe on the - test point next to it, and the positive probe on the - test point of the right most LED. i.e. the circuit from the TV starts first with the LED right of the connector, and to the next 2 LEDs on the right, and the right-most LED is then connected to the left most LED, and then so on until the LED just before the connector, and then to the connector
      Attached Files
      Last edited by lmcancu; 03-20-2023, 07:41 PM.

      Comment

      • lmcancu
        Senior Member
        • Oct 2009
        • 158

        #4
        Re: LED Strip test points and testing?

        Updated with corrected diagrams
        Attached Files

        Comment

        Related Topics

        Collapse

        • thetonywarren
          TCL 43S435 NO BACKLIGHT ISSUE, LEDS TEST OK
          by thetonywarren
          I have a TCL 43S435 with no backlights. I contacted ShopJimmy and they said power supply. I got replacement power supply, but still doesnt work. I have confirmed that there is an image with flashlight test. I have also verified that the led strips work when I probe them with LED tester. Any ideas would be helpful. I am also geting a double blink on the status led when trying to turn it on......Nothing on the power supply looks suspect, and caps look ok. Where should I start to test......Thanks!...
          04-23-2025, 10:48 AM
        • 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
        • howardc64
          A1312 (27” iMac 2009-2011) A1407 (Thunderbolt Display) A1316 (Cinema Display) Display Black Screen Repair
          by howardc64
          Problem

          This is an LG edge LED lit LCD Display. The LEDs are on the bottom edge of the display. There are 2 bars (left and right) Each bar has many LEDs and a 6 pin connector. Each pin drive several LEDs thus is the highest current flow / heat junction. The weak lead free solder gradually fails with thermal expansion/contraction cycling and increases resistance. PSU will compensate up to a point, then when the current is too high, PSU just shut down the backlight causing a dark display. I have even seen one which the connector just fell off as solder points became completely detached....
          08-04-2024, 10:36 PM
        • Ukdigger
          Jvc lt-50c750 2 Seconds To Black
          by Ukdigger
          JVC LT-50C750. Power board Vestel 17IPS71

          TV shows the JVC logo for a couple of seconds and then no picture. I thought it would be the same fault I had with a JVC LT-50C550 where 3 LEDs had failed but the strips seem to test ok individually, 4 lots of 7 LEDs, middle strip has 8 LEDs and 3 connectors, half of them light up with 2 connectors 14.6v and the other half light up with different 2 connectors 14.6v. When I test the LED strips with a tester they read 90.2v and 68v. If I plug them back in and start the TV it works perfect all day until it is switched off for a period of time...
          03-31-2023, 09:06 AM
        • tmhobadcap
          TCL 65S403 Backlight LED Question
          by tmhobadcap
          I got the TV from a friend. He claims that no image but sound from the TV.
          I confirmed that when shine a flashlight on to the screen, I can see the image. And this should be backlight problem.
          I open up the TV and found a few leds failed. And now I am ordering a new set of backlight strips for it.

          But there is something that I do not understand when checking the leds. I do not have an led tester. I only use a bench power supply. I first set the voltage to 3V and current to 10mA. I could not light up the led until I increase the voltage to 12V. I understand most...
          05-25-2025, 11:03 AM
        • Loading...
        • No more items.
        Working...