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Why is LCD TV backlight flashing?

Samsung LN-T4065F LCD TV 40"

The TV is 10 years old and has 5700 viewing hours.

The backlight is flashing on and off at a rate of about 3 times/sec. You can see a video of it here:

This used to happen periodically then go away overnight. Now it's not going away.

How can I debug if this is an inverter problem? I have a multi-meter. Or should I just buy the $17 inverter and hope for the best?

Answered! View the answer I have this problem too

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1 Answer

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The backlight inverter is damaged. Needs to be replaced. Requires soldering. You could send the board off to a board repair shop in your area or mail in

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What kind of soldering? Videos I've seen show that replacing the whole board is basically plugs/wires.


You could do that. Would be much easier


Did some multi-meter tests on the inverter. Couldn't find any problem. I'm just going to spend the $17 for the new inverter board and see if it fixes it.


Ok. Let us know if you need anything!


New inverter fixed it!


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Matt will be eternally grateful.
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