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[Solved] Toshiba 40l1333b - SSL400_05DA - backlight problem

dfear 07 Nov 2018 20:13 828 2
  • #1
    dfear
    Level 3  
    I have a Toshiba 40l1333b with a backlight problem.

    Problem:
    The backlights don't light up.

    Screen: Lta400hm23
    LED Driver board: Ssl400 0d5a- Rev 1.0
    Back light LED Strip connector board: SSL400_WP01 REV:0.0

    Firstly I replaced the driver board, but that didn't fix the problem.

    with the replacement driver board connected, I tested the led strips with an LED tester and all the leds light up.

    I tested the leds using test points VOUT and IS (which are on the led driver board).

    Also i have checked the continuity from the led driver board to the led strips, and continuity is OK.
    I think there is a fault with the led driver board. I have attached two photos of the led driver board. The photo with just black test shows what the voltages should be at various points (i found these voltages from a photo I found on a forum). The second photo ( with the green text) show the results of testing the replacement driver board.

    ---------------------------------------------------------------------------------
    Any clues which component on the led driver board in faulty?
    ----------------------------------------------------------------------------------

    Update: I replaced the SN358 op-amp with with a LM358, but it made no difference.


    Here is a number of photos with varying test results
    -----------------------------------------------------------
    correct voltages on SSL400_05DA
    [url=http://testing.dfear.co.uk/toshiba_40l1333b/151120-IMG_20151120_221823.v2-1.black%20text.png]

    results of testing original SSL400_05DA (from the tv)
    [url=http://testing.dfear.co.uk/toshiba_40l1333b/151120-IMG_20151120_221823.v2-1.black%20text.original%20board%20-%20test%20results.png]

    results of testing replacement SSL400_05DA
    [url=http://testing.dfear.co.uk/toshiba_40l1333b/151120-IMG_20151120_221823.v2-1.black%20text.replacement%20board%20-%20test%20results.png]

    results of testing SN358, TR10E and CN001 - original SSL400_05DA
    [url=http://testing.dfear.co.uk/toshiba_40l1333b/original%20-%20ic%20results.png]

    results of testing SN358, TR10E and CN001 - replacement SSL400_05DA
    [url=http://testing.dfear.co.uk/toshiba_40l1333b/replacement%20-%20ic%20results.png]
  • #2
    dfear
    Level 3  
    I have fixed the backlight problem on this TV.

    The problem was the crappy connectors that connect the led strip pairs together.

    Solution:
    I have soldered solid copper wire jumpers between the pairs of led strips. Only one connection was faulty but I put copper jumper wires between all of the led strip pairs, on both the positive and negative connections.

    FYI:
    The voltage on the LED tester (after the repair), when putting the probes on the IS and V_OUT test points on SSL400_05DA, was 124V.

    FYI:
    I used the solid copper wire from 1.0mm2 twin and earth electrical cable to make the jumper links.

    Toshiba 40l1333b - SSL400_05DA - backlight problem
  • #3
    dfear
    Level 3  
    I have fixed the backlight problem on this TV.

    The problem was the crappy connectors that connect the led strip pairs together.

    Solution:
    I have soldered solid copper wire jumpers between the pairs of led strips. Only one connection was faulty but I put copper jumper wires between all of the led strip pairs, on both the positive and negative connections.

    FYI:
    The voltage on the LED tester (after the repair), when putting the probes on the IS and V_OUT test points on SSL400_05DA, was 124V.

    FYI:
    I used the solid copper wire from 1.0mm2 twin and earth electrical cable to make the jumper links.

    Toshiba 40l1333b - SSL400_05DA - backlight problem

    Dodano po 6 [minuty]:

    I have fixed the backlight broken on this TV.

    The problem was the crappy connectors that connect the led strip pairs together.

    Solution:
    I have soldered solid copper wire jumpers between the pairs of led strips. Only one connection was faulty but I put copper jumper wires between all of the led strip pairs, on both the positive and negative connections.

    FYI:
    The voltage on the LED tester (after the repair), when putting the probes on the IS and V_OUT test points on SSL400_05DA, was 124V.

    FYI:
    I used the solid copper wire from 1.0mm2 twin and earth electrical cable to make the jumper links.


    https://obrazki.elektroda.pl/7825770300_1541702334.jpg
    Toshiba 40l1333b - SSL400_05DA - backlight problem