[SOLVED]820-2915 no backlight

[Dozer]

hi,

i am just working on that board

have video with lamp behind the lcd but no backlight.

i already figured out that the pwm signal is 0V and without R9704 and 3.3 V direct on U9701 Pin 4 i get nice backlight

so i thought (R9704 both sides is 0V) the GMUX is the prolem

i reballed the GMUX but still the same problems

is here the GMUX bad ? or what signals has to come in for a good PWM output?

is the GPU involved?

 

[dukefawks]

PRAM reset?? Else the MUS is bad. And next month the GPU will die.

 

[Dozer]

thanks for your answer

so the PRAM reset is without change

i will goibg forward to replace the mux. is it possible to take any from any 2915?

 

[Dozer]

so, gmux is replaced and Duke, thanks, backlight is back !! yippii