Sharp LC-46D64U Inverter/Backlight Repair?

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  • Kiraisuki
    Member
    • Jun 2017
    • 12
    • USA

    #1

    Sharp LC-46D64U Inverter/Backlight Repair?

    I found an old Sharp LC-46D64U LCD TV on the side of the road and decided to pick it up. It would turn on for about 30 seconds, revealing that the backlight was not functioning properly (half the screen was dark) before shutting off and blinking an error code indicating something had gone wrong with the lamps and inverters. After much troubleshooting and researching, I managed to find the maintenance manual. In it, I discovered that holding Vol+ and Ch- made the TV power on and stay on as if nothing was wrong. The backlight would still shut off after 30 seconds, and it still was half-dark, but by holding a light to the screen with a laptop plugged in, I could see an image and hear sound.

    I looked online and discovered that replacement inverters and lamps were very expensive for this TV, but the rest of it worked fine so I couldn't just dump it or part it out. So, I removed the inverters and the lamps, and replaced them with a bunch of externally-powered LED strips. The TV now functions semi-normally and is completely usable, except for three things:

    ~ The "backlight" must now be turned on separately

    ~ The TV must be turned on using Vol+ and Ch- if it loses power or is unplugged, and

    ~ due to the dimmer LEDs, you can clearly see many dark spots on the screen.

    I was wondering if it would be possible to repair the inverters of this TV and get it back in fully functioning order, and someone elsewhere said this was the place to be. There are 4 inverters on the TV, powered by two separate 12v/60v/GND 3-pin power points on the main power board. They each have a model number, RUNTKA###WJZZ where ### is 323, 324, 325, and 326. RUNTKA323 seems to be the main control inverter, as it has an LM2901 voltage comparator and an OZ9928SN CCFL backlight inverter controller, whereas the rest of the boards have only small unlabeled components. The capacitors look fine on all of the boards, but I'm no expert. I had a friend look at them, and they labeled two of the boards as bad, but they did not say why, and I cannot contact them any more. Attached are several images of the boards.

    Any help is appreciated, and feel free to ask for any information you need.
    Attached Files

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