no display even after changing item Q9400

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A few weeks ago, my Macbook pro(A1212) stopped displaying. It only showed a white screen, but you could get the display via an external monitor. A friend looked at it and we discovered a burnt Mosfet (SI3443DV) which was item Q9400 on the motherboard. He went and changed it but it only displayed for less than 5 minutes and it went back to the white screen. would you please advice on what to do since i am not in a financial position to take it for repairs at the apple store?

P.s The component is pointed out on the image above.


Answered! View the answer I have this problem too

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Could you post a picture of the board and point out the component that you replaced. This would help us figure out the problem allot better.


Hi john, i uploaded an image with a pointer to the component on the original question. Thanks for your help.



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It sounds to me like the new one has burnt out as well. Was it orientated the correct way? I know that Mosfets are used as power protection and load switches. It is very possible that burned out because it is acting as power management and builds up allot of heat. I think it would be interesting to open the computer back up and take a look.

Hope this helps,

John H. Laney

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Joe will be eternally grateful.
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