Macbook Pro 13 no function with Ram

[gerikerschi]

Hi!

I have a Macbook Pro 13 from 2010.
Last week the macbook is fallen on the floor.
Since this time it does not boot.
I can turn on the Macbook, but after this no sound, no POS-Test and a black screen. The power led lights and the fan turns.
Apple write, that a black screen with the power light on is a problem during the POST or boot ROM failure.
When I remove both Ram, I hear one beep sound. With Ram no function.
I also use other Ram to test the Macboot, but also the same problem.
How can I find the root cause for this problem?

BR
Gerald

 

[maflynn]

How can I find the root cause for this problem?

Sounds like the fall damaged the computer, perhaps the logic board or some other component. I don't think you can find the root of the failure.

Take it to apple and see what they say and how much it will cost to repair.

 

[gerikerschi]

Thanks for the answere, but I wan't to repair the board by myself.
I have the schematic and the board view of the A1278 2010 and a good one to check the voltages.
I would like to understand where the problem is approximately on the logicboard.
I am also sure, that this is a logicboard problem.

BR
Gerald

 

[maflynn]

If that's the case, you need to check each component and see if the voltage readings are identical. I'm not sure how viable replacing surface mounted components are but good luck

 

[gerikerschi]

Problem found!

Problem found without checking all components!
I measure all test points from the schematic and I found a problem by the U1400 graphic chip.
No current on J9000 pin 2 and 3.
The LCD_IG_PWR_EN signal is missing.
So the graphic chip has an open contact.

BR
Gerald