Kawi2strokes.com Forum

I have a TCL 65" LED tv that is about 3yr old. It quit working.... sound, no pic.
I used to repair tvs for a living about 45 yr ago... they've changed!

I decided I'd see what makes these things tick and maybe repair it myself. I found that t hey are really pretty simple and all of them have a similar design. There are only 5 PC boards that contain most of the working components and those boards are available to purchase on Ebay at a fraction of the cost of a new tv. Time to give it a go!

There were only 3 of the boards that could cause my problem. I ordered the most likely... didn't fix it. Ordered the other two and that didn't fix it either. After doing some more research I discovered that my problem was the LEDs used for backlight were not functioning. There is an LED driver board that supplies power to the LEDs that are backlight and power was available from that board but no backlight.

In an LED tv there is a backlight made up of numerous LEDs that give off a white light. That light shines thru the screen panel to give a picture. In my 65" there are 84 LEDs... 12 strips of 7 each.

It is a major job to get to the LEDs for testing and/or replacement... a small screen wouldn't be too bad but a 65" is a bear. The front screen must be removed from the bezel, etc, etc.

Once I finally got it apart and checked the LEDs with a home made tester I found 27 of 84 LEDs were bad.... one complete strip of 7. I have replacements ordered.

The whole point of posting this is to let everyone know what I learned during my research. LED tvs have a manual adjustment to set BACKLIGHT. It ranges from 0-100%. Mine was set at 100% as received from factory. It is recommended by the tv repair community to reduce that setting to as low as possible in an effort to minimize the premature failure of backlight LEDs. No more than 80% is recommended. I have mine now on 60% without noticing any detrimental effects on picture.

The purpose of backlight control is to increase the brilliance of picture in a brightly lit room. Don't confuse it with brightness & contrast controls. Brightness controls the intensity of dark or blacks on the screen. Contrast controls the intensity of whites or light colors on the screen.

Hope this might save you repairing or buying a new tv when it is avoidable.

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Answers are here: http://kawatriple.com/

Cool stuff eh Dale?
Thanks for the post.

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Bad decisions make the best stories.

Cool info thanks!

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This is true. Where I grew up the hills were so steep and long, when your ball rolled down the hill you just said "screw it"...

Good info to have.

Huh, interesting. I have a large LCD monitor I just replaced because it was 'dull' from new, but the picture is good. I bet its that, will see if I can find the backlight adjustment, inside the case I guess.

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.

If I'm not mistaken, this is an LCD screen backlit with LEDs, which is an improvement over the old fluorescent backlit version.

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If it surges, that's normal, upshift.

Yes, Jim, that is correct.
The backlight control is a function of settings or advanced settings. It may be called something else on some models. LG calls it "Picture".
One or two of the LEDs may fail without serious problem, however, because of how they are connected, a failed LED can cause the LED driver board to shut down to prevent further damage and the screen will go black. The screen image is still there but you must use a flashlight held at the right angle to see it.

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Answers are here: http://kawatriple.com/

Yes, I've had the older fluorescent backlit type quit so I know the flashlight trick. Luckily the newer LED lit versions are more reliable than the tiny, delicate fluorescent tubes.

I have a few champagne bottles of trappist ale that's now over a year old. You think you might be there this year?

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If it surges, that's normal, upshift.

Good stuff...thanks for the info......but after all you did, TV's being so cheap these days, wouldn't it have been better to just go buy a new TV !


Nahhh...I replaced a light in mine for about 40 bucks. It took a couple days to get the part and maybe 30 minutes to replace.

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Busy doing more riding than wrenching.......

Dale!

Are you being anal? :roll

Why and how things work?


Umm-i tink i no someone i kno.


cliff

p.s.
my $ is on a broken circuit trace on a board with the 65"