Persistent Backlight Problem with Philips 65PUS6554 12 TV

@harqenzo There are now only two possibilities left. One is a bad panel (LCD driver boards) and the other possibility are the back lights. I have now had a few instances where they lit up with a tester but did not work from the power board. Check this quickly by shining a flashlight beam against the screen (in a darkened room) on a channel where you have sound. See if you can make out any shapes, silhouettes etc. If so, it is your backlight strips that need to be replaced.

A panel error usually still shows the backlight, just no video. OF course you can always try a tape-off AFTER the backlights.

Have you tested the led's with the multimeter? Remember they have a positive and negative side. Check them and if one is shorted you could bypass it with a jumper wire. There's a guy on YouTube with a video on how to do it. Personally I'd turn on the TV with the leds exposed and the screen disconnected and if they light up leave it on and see if they go out after half an hour.

The output voltage from backlight driver is 20% higher than the recommended voltage. This is VERY COMMON design of Philips tv. If u replace ALL backlight strips to brand new - then the tv will light up normal. However it may last 1 yr or less. If u reduce the backlight driver output voltage for recommended voltage - the backlight will last 7-8 yrs.

To reduce the backlight driver voltage - you need to tune the bias voltage at the BL IC - which is best left to experts.