[SOLVED]820-3437-b no backlight

[Gannons3]

I have a macbook air with no backlight, I get a picture but no backlight, i have no idea where to even start measuring for problems on this thing. There has been no liquid damage on this board at all. thanks for any help you can give

 

[dukefawks]

Read the sticky topic on this first and report some measurements.

 

[Gannons3]

I get 0v on pin 2 of r7731 the bkl_en line. i do get a picture

 

[Gannons3]

f7700 is good

 

[Gannons3]

.582 in diode mode from pin 2 r7731 to ground

 

[dukefawks]

Voltage on L7701?

 

[Gannons3]

basically 0

 

[dukefawks]

EDP_BKLT_EN coming high? SMC_LID high?

 

[Gannons3]

3.34 on edp_bklt_en
3.47 on smc_lid

 

[dukefawks]

Voltages on Q7706?

 

[Gannons3]

0 on pin 6
0 on pin 5
0 on 4
0 on 3
0 on 2
0 on 1

 

[Gannons3]

never mind, im an idiot the fuse must be bad, im getting over 8v on pin 1 of f7700 and 0 on pin 2

 

[Gannons3]

Yup replaced f7700 and i now have backlight. Thanks for the help!