820-3332-A No Backlight

[tlough75]

Ok, So I have an 820-3332-A that has no backlight. Image it confirmed with flashlight. F9700 is not blown. I checked BLK_EN and it is at 2.8V. Could use a little guidance on where to check next.

 

[2informaticos]

Any history available?
Post exact voltage at pin 1 of J9000 and pin 2 of U9701.

Did you try known good compatible LCD assembly?
Also do few times PRAM reset.
Post diode mode to ground on both pins of D9701.

 

[JohnB8812]

And also resolder U8900 after fixed

 

[tlough75]

Ok, So I discovered the LCD cable was damaged so I replaced it. No change. went to measure F9700 and it was popped. Replaced that and we now have back light restored. Now I gotta tackle the issue of not seeing the keyboard or trackpad. Any Ideas on that? BTW a little history on this machine. No reports of liquid damage though I am sure it has been dropped once or more, the back corner of the machine is ever so slightly bent. board looks really clean though I have not removed it.

 

[2informaticos]

KB/TP not working before and once entered OSX too?
I recommend to try known good TP flex as first stept; is the most common failure.
Next step, try good TP board.

 

[tlough75]

ok, thanks! I will try that. as far as I know, the T-Pad and KB were not working before and once I get into OSX. But the "power" button works.

 

[2informaticos]

Power button "remains" on the MLB.
The rest of keys go to PCH through trackpad cicuitry.

 

[tlough75]

Gotcha, thank you.