Samsung BU8500 TV screen problem white screen then flickers to black

Hi @hal_fixit

Seems as though this is a reasonably new model i.e. ~2022 is this correct?

If so then I'm not sure if the following test will work but worth a try maybe. This used to be the standard Samsung troubleshooting test on earlier models to initially determine if the problem was in the LED backlights, the power board or the mainboard

Disconnect the power to the TV, remove the back cover and then disconnect the power board - mainboard cable at the power board end only.

Reconnect the power to the TV and turn it on.

Normally if all was good the backlights would turn on and stay on. There is no display/audio as the mainboard is disconnected.

If the backlights flicker or don't turn on at all, this narrows it down to the backlights or the power board.

I can't find a decent image of the power board (BN44-00947G? I think) so I'm not sure how many backlight strips are being supplied by the power board.

The next test is to disconnect the LED backlight power cable from the board and measure the voltage on the power board backlight connector pins. Do this between the LED + pin of each feed and an Earth point (screwhead) and not between the +ve and -ve LED power feed for each strip. Check that the voltage is stable and not fluctuating to a large degree.

Looking at images of the power board there appears to be some LED reference jumper links near a connector so maybe check the voltage on it (are they LED1+ and LED1- can't tell too faint and my eyes are gone anyway). Also check for any info on the board pertaining to voltage levels as they may give some idea. Be safety aware as it may be between 150V-280V DC

Be safety aware in general as there is exposed lethal AC voltage on the power board