820 2523b no backlight

Modder1

New member
f9800 12.6V
r9808 pin1 12.61 pin2 12.24
R9802 pin1 12.61 pin 2 12.24
R9809 pin 1 12.07 pin2 12.61

Q9806 Pin 1=0V
pin2=0V
pin3=12.24
pin4=12.6
pin5=0V
pin6=0v

L9701=0V pin 1 and 2
u9701 pin23=0V
 

Repairable

Active member
random measurements?

does it chime,?
have you got fan spin?
liquid damage?

known good screen and kabel?
can you see apple logo when putting a light on the back of the screen?
 

Modder1

New member
I am not sure what you mean when you say "random measurements"
It does chime
No fan spin when board is out of casing, unsure if it spins when in case
No liquid damage
Yes good screen and cable
Yes I see apple logo
 

dukefawks

Administrator
Check pin 2 and 5 of Q9807 again. I don't believe both of them are low. Screen needs to be connected of course!
 

Modder1

New member
just the screen and the magsafe plugged in I get 0V on both pin 2 and 5 of Q9807
I am using a schematic that says 850-2523 not 850-2523b if this is my issue
 

Modder1

New member
4.7 kilohm on pin 5 of Q9807 in diode mode
1.35 milliohm on pin 2 of Q9807 in diode mode
0.44V on pin 5 of Q8907 in resistance mode
0.43V on pin 2 of Q9807 in resistance mode
 
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