Black screen but with sound and ambilight working

Hi,

Don’t know your model, but is the Ambilight only on two sides or three?

The Ambilight only uses a few LED strips (one each side and not sure but maybe on top or bottom as well), but it seems as there could be a screen LED backlight problem, either with the backlights themselves or in the power board. Less likely is that the problem is in the mainboard which signals the power board to turn the backlights on and off as the Ambilight is working, there are images on the screen, even though they are faint and that there is audio as well so it seems to be mostly operating correctly.

Here’s the service manual for the TV which may help. It has the schematic diagram of the LED driver circuit (see p.34 of 52) so that the section of the power board powering the LEDs can be inspected and the voltages tested etc. If the voltages to the LEDs are OK then the LED backlights / backlight array would have to be accessed and tested to find the problem. This would involve disassembling the screen.

Be safety aware when testing in the back of a TV with the power connected, as there is exposed lethal voltage on the power board near to where you are testing.