820-2936 not backlight

[andrespi]

hello this macbook after a maintenance that i did now it does not work backlight.the macbook have image but no backlight,I also tried with a screen in good condition but the problem persists
these are some measure
f9700 its good
D9701 PIN1=12.58
D9702 PIN2=12.56
Q9706 PIN1=12.59
PIN 2=12.59
PIN3=4V
PIN 4=12.59
PIN 5=12.59
PIN 6=12.59

 

[2informaticos]

Post BKL_EN and BKL_PWM levels.

Just in case, do PRAM reset 2-3 times.

 

[andrespi]

BKL_EN=3.1 v
BKL_PWM=1.9v multimeter, BKL_PWM levels need oscilloscope?
PRAM reset 2-3 times persists problem

 

[2informaticos]

Remove R9704 and run wire from R9715 to C9704.
Check if backlight comes on.

 

[andrespi]

not backlight on, after of wire from R9715 to C9704

 

[2informaticos]

Post again BKL_EN/PWM.

 

[andrespi]

Remove R9704 and run wire from R9715 to C9704
BKL_EN=3.1
PWM=3.1

 

[2informaticos]

Post again D9701 voltages.

 

[andrespi]

D9701
PIN1=11.90
PIN2=11.89

 

[2informaticos]

Change U9701.
Be sure to get good solders.
Once the chip is removed, check traces between D9701 and U9701 pads.