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Samsung 40" TV - no picture - LED reacts on RC

The screen of my Samsung 40” TV stays black when I turn it on.

The red standby LED does react when buttons on the remote are pressed.

I opened the TV and I don’t see any clear damage (e.g. burn marks, leaky capacitors).

Model: UE40K5579SU

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MB: BN41-02534B

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PSU: L40E1_KDY

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When I turn it on with the back cover removed, the backlight is off.

When I disconnect the main board from the power board the backlight turns on.


Any ideas what might be the cause and/or should be replaced?

Other tips for fixing the issue?

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crwdns2944067:02crwdne2944067:0:

Hi @wlf ,

Might seem odd, but try shining a torch at an angle close to the screen to see if there is an image or not when the TV is on.

I realize that the backlights work but maybe the mainboard isn't telling the power board to turn them on.

Also having no audio is not a good sign.

It appears to be a mainboard problem or perhaps a software problem.

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There is no image on the screen with the torch test.

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Hi @wlf

No audio and no video but the backlights work OK indicates a mainboard problem or perhaps a firmware problem although the TV reacts to the remote control.

It shouldn't be a tcon problem either because there is no audio and the tcon would only affect the video

You could try re-installing the firmware (go to Downloads) and check if that resolves the problem. There is a document in the downloads area that shows how to do this.

It may work as the USB port is checked early in the power on procedure to see if there is any update file present and if not it continues turning on.

Don’t know for sure but I’m think that perhaps this area of the firmware might be safeguarded so as to enable reloads in case of corrupted firmware.

IMPORTANT - please ensure that the full model number of the TV is exactly the same as the link I posted because if the incorrect firmware is loaded it will brick the TV and then the only way to fix it is either a new eeprom with the correct firmware installed or a new compatible mainboard. Perhaps do your own search online for Samsung (insert full model number) support and check what you get.

Otherwise if the firmware reload option doesn’t work you may have to replace the mainboard. Try sourcing the replacement from a supplier that offers refunds for only a small restocking fee so as to minimize the cost to you if it is not the problem

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