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A1466 820-00165-A backlight dont work

L

lincev

Member
Hello, I have searched the forum for other messages but I have not seen anything similar to my problem.

The equipment turns on and after a second the backlight does not work. With a PRAM reset now the device keeps the backlight until almost the end of the block and it disappears, it gets to the user screen and it still doesn't work. I have done several PRAM resets and I have tried another screen but the same problem..

any ideas? thanks !
 
2informaticos

2informaticos

Administrator
Staff member
Any history available?
Check BKL_EN/PWM when the problem appears.
What is backlight output voltage behavior?
 
2informaticos

2informaticos

Administrator
Staff member
Test starting in safe and also SMC bypass mode.

Backlight always present if keep the machine in boot menu?
 
L

lincev

Member
It doesn't work in safe mode at any time. And I have tried three pram resets and neither.

Before at least it worked a few seconds after the pram...
 
2informaticos

2informaticos

Administrator
Staff member
Remove R7704 and run wire from 3V3_S0 to BKL_PWM.
Confirm if you get full backlight; no adjust possible.
Then do PRAM reset 2-3 times.
Remove the wire and put back R7704; still working?
 
L

lincev

Member
hello again, I remove R7704 and run wire from C7711 (point 1 PP3V3_S0) to R7704 (point 2 BKL_PWM) but I don't get full backlight, too I try 3 times pram reset
 
L

lincev

Member
hi again, sorry but I replace L7701 and D7701 and same problem... I have 8,52v

I try 3 times pram.. arggg board ! ;D thanks
 
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