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A1466 no backlight , Image is present

M

manumathew.017

Member
I have 8.5V o/p, Seems like boosting is not occurring, Changed the driver IC, The feedback is proper (Checked the continuity from D7701 second pin to A5).
I have 2.8V BKL_EN . I am ....STUCKKKKKKKKKKKKKKKKK.........................
 
2informaticos

2informaticos

Administrator
Staff member
If is not secret, can we know what board do you have on the desk???

Did you try known good LCD assembly?
BKL_PWM level?
Try 2-3 times PRAM reset, just in case.,
 
M

manumathew.017

Member
I dont have extra lcd for trial,
BKL_PWM - Its high If I am not wrong it is 2.1V.
PRAM reset didn't help
Revealing the secret Board is 820-00165A
 
2informaticos

2informaticos

Administrator
Staff member
Check R7717-22; post diode mode to ground on all them.
Also at both pins of D7701.
Post real BKL_PWM level.
 
M

manumathew.017

Member
I have resoldered the backlight chip, Now when I start there is backlight ,,,,
When I reboot no backlight. Once starts then it keeps working. Does it a software issue or I should resolder it again?
 
M

manumathew.017

Member
I have resoldered properly... Now the backlight is working ..... Only one issue...

There is 16 different brightness control by pressing the F1 and F2 key (Low to High), Only on the 15th position of brightness does it's flickering. I mean brightness doesn't stay stable. It's slightly flickering.
 
M

manumathew.017

Member
Seems like back light issue solved...
Now when I press the power button sometimes it boots, sometimes it doesn't boot or no chime sound just Fan is rotating continues, Tried pram reset and Cleanme... Doesnt help
 
2informaticos

2informaticos

Administrator
Staff member
Didn't note this problem before changing U7701?
Shouldn't be caused by this change however.

CPU core comes high, PLT_RESET_L present?
 
M

manumathew.017

Member
Connected an external SSD ---> Removed the internal SSD ---> System booted properly, But after 3rd restart, it again went to that weird mode (Fan running not booting)----> Measured PPVCC_S0_CPU at weird mode= 1.808V
 
2informaticos

2informaticos

Administrator
Staff member
SMC_LID puts system to sleep, when lid is closed.
An incorrect level can cause weird issue; if fluctuates close to its threshold voltage.
 
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