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Mid 2009 Model A1278 / 2.26 or 2.53 GHz Core 2 Duo processor EMC 2326

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Backlight defective, external display works. Change motherboard?

While replacing a defective HD with a new SSD I must have done something wrong (maybe hit a fuse...).

The laptop still works and I can use it attached to an external display but the internal display has no more backlight (the backlit keyboard still works). The LCD is not defective because I can still see an image on it very faint when I shine a torchlight on the screen.

I brought it into my local Apple shop and they want to replace the motherboard (big cost!!!) but I saw some threads on replacing the fuse ore wled driver. This requires knowledge of the motherboard and where to look for these pieces. I will not attempt to do this myself but maybe with the right information I could get a specialized shop to do the task. Any help with schemes or tip is welcome.

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Erik, that might be a possibility. what are the last three digits of your computer? Do you have a number on the motherboard? It will help us to identify your computer and logicboard properly and possibly find what you are looking for. Also post some high res images on here so that we can may be point those components out to you.

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Erik, here is what I got with the limited information available. The fuse is a 2 AMP-32V 0402-HF SMD fuse, and something like this should work for your board. The WLED driver is a LP8543 made by TI. the datasheet is available right here. Mouser.com as well as Digikey.com should have both parts available. Hope this helps,good luck.

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Hey Oldturkey, thanks for the info, I will open up my laptop again to check if I can see any damage to any of these pieces...would you happen to know how to check if these are defective? (with a resistance meter?)

Thanks,

Erik

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You can check the fuse with a multimeter for continuity. If you have no continuity you know that it has failed. The IC will be lot tougher. You need to check with the data sheet to see which pins you should check. I would suggest to start to check pin 22 and pin 23. On 23 you should have 5.5V to 22V and 22 1.65V to 5.5V. Follow the datasheet for further testing. Make sure you do not shorten out any of the pins when you measure with a meter probe.

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Erik will be eternally grateful.
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