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Sound but no picture

Nothing has changed, but suddenly the TV has sound but no picture - no menus, nothing. Model is Aquos LC-40CFG4041K.

We've taken the back off, and there appears to be a wire that's a bit damaged, I'm wondering if anyone can tell us what it's called so we can get a new one?

Also, feel free to squeak up if you spot anything else that looks wrong!

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@sazu I have old people vision and can’t quite make out where the wire connects too. It looks like what I would expect to go to the backlight array but can’t be sure. Can you point to the connectors on your images? Also, what damage do you see. One of the wires could be cut.

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Hi Sazu,

I'm not sure I'm seeing the damage you're referring to in the first two pictures. If you're talking about the gap between the two wires on the right and the four on the left, that shouldn't be an issue unless there's something else that's not apparent in your pictures.

One of the most frequent causes of no picture issues is a backlight failure; the LEDs behind the LCD panel provide a light source that's filtered by the LCD into a picture, so when the backlights go out, the screen looks black, but that's just because there's no light coming through. You can check if that's the issue by holding a bright light up close to the screen and seeing if you can make out an image that way. If there is a picture, then it's only the backlight that's not working, and that's fixable.

I've most often seen backlights fail because individual LEDs fail and once enough of them go out, the controller will then refuse to power the screen as it sees the voltage being wrong. If that happens, the cure is to replace the backlight strips, at which point the control board will read the correct power and light up the screen again. If you're handy with a soldering iron, it is possible to replace individual LEDs, but the problem is that being all the same age, as some of them fail, that'll be followed by more of them going out so you'll be in a repeating cycle of, open the TV, fix the dead LEDs, put it back together, then a few weeks or months down the road do it all again, so it's best to just replace them all once enough fail that they won't light up any longer.

There may be further diagnosis that can be done once you've determined if the backlight is at fault that other contributors can help with, but as your first step get out a flashlight and see if there's a picture present or not. Come back and post what you find and we'll figure out what your next step should be.

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@sazu like my esteemed colleague above already stated, it is possible that this is a backlight issue. Easiest test (pretty much as above as well) would be to verify that you have no image on all inputs. If it remains dark, unplug it (and everything you have connected to your TV like cable box, sat box, coax, whatever is connected even HDMI cables) and push the power button for about one minute, then plug in one input source (preferably a local one like DVD/BR/Game Console etc.) and then plug the TV back in. See if that resets your TV.

If it remains dark, in a darkened use a flashlight and angle it against the screen with the TV at a channel where you can hear the sound See if you can make out shadows or shapes. If you do, then it is your backlight that has failed. If you do not see anything, unplug your set and remove the back. Looks like your boards are pretty clean but a couple of sharper images of both boards could be helpful. Check all the wiring and unplug the wires (even the flat ribbon cables) and plug them back in to make sure they are properly seated. It is possible that this is either a power board issue or a T-con board issue. On the T-con board, which is the board top right in your second pictures, to the right side of connector CN1 you should find a component labeled F100. that is a fuse. Use a multimeter and check that fuse for continuity and with your TV on (THIS IS A HOT TEST so do not touch anything with your fingers) measure the voltage on the fuse. You should get 12VDC on it. Remember it is DC so set your meter accordingly. Black to ground and red probe to either side of the component. Let us know what you get on that.

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Sazu A zal eeuwig dankbaar zijn.
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