820 2915 no backlight

[Roan]

Hi, I have a no backlight 8202915 in front of me with 24.7V on the LCD backlight rails. I assume this is a voltage which should make the backlight turn on. The PWM rail to the backlight driver has 2.3V which is maybe low? I have too little experience to tell. Backlight driver faulty which makes for too little boost and just not a high enough voltage?

 

[2informaticos]

For this 15" screen, backlight voltage should be higher.
Doesn't increase using control keys?
You should note PWM level changing.

Any history available?

 

[Roan]

Happened on its own. But I can see from the partially yellowish tin that the board itself is refurbished. Also the GPU has been disabled. The costumer changed his mind and does not want to continue the repair. Thanks for the help, at least learned another thing about the PWM