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Old 06-22-2015, 03:39 PM   #1
Join Date: Jun 2015
City & State: England
My Country: UK
I'm a: Knowledge Seeker
Posts: 60
Default Apple MacBook Pro 820-2530

Hi everyone,
I'm needing some guidance tracking down this fault.
The logic board starts up with fan spinning full speed, and originally I thought it was just a backlight problem as there's no input voltage on the backlight driver chip as well as no enable voltage - Although there is 12v at the fuse F9800.

However when I shine a light at the back of the screen there doesn't seem to be any video there either. Also there's no chime when it starts.

I have the schematic and matching boardview file, and using this I seem to have all the correct power rails apart from the missing power at U9701.

This rail reads around 400k ohms when measured to ground so I'm not sure if that would count as short? I'm also not sure if a short on this rail would stop the video and the chime??

Any help GREATLY appreciated !
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