MacBook Pro 13" 820-3115

[hamed57]

I have a macbook pro 13" with no backlight.
Everything else is working well.

My measurements:

backlight fuse: 12.55v
LVDS pin 21 and pin22: 12.54v
C9020 pin1: 12.52
C9020 pin2: 0.0

Board looks good under the microscope. I ultrasonic cleaned it and I slightly reflowed U9701.

Any hint at this point?

 

[aprendiz]

Voltage on BKL_PWM and BKL_EN???

 

[hamed57]

Voltage on BKL_PWM and BKL_EN???

BKL_PWM: 3.290v

BKL_EN: 3.100v

 

[aprendiz]

all seems to be ok but U9701 is not boosting, replace U9701, when take off the IC, confirm continuity on feedback line.....

 

[hamed57]

all seems to be ok but U9701 is not boosting, replace U9701, when take off the IC, confirm continuity on feedback line.....

I have replaced the u9701. Same result! no backlight but I have image

 

[aprendiz]

DId you confirm comtinuity on feedback line???

 

[hamed57]

DId you confirm comtinuity on feedback line???

I did it before replacing the u9701

 

[dukefawks]

Diode mode on the BKL output line? D9701 check for short? All the voltages are there so it must be in the U9701 boost circuit.