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

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LCD not working after replacing thermal paste.

I recently changed the thermal paste on the heat sink by going through instructions stated in this website. I cleaned everything on the processor and GPU and applied the new arctic thermal paste. However, after I put up everything together and powered it up, the LCD didnt work. The apple logo on the front panel is not lighting up either. The external works fine. Checked all the connectors and everything is hooked up as it is supposed to be. I am not sure if it is the graphic card or something else but the LCD is not getting power. Please suggest something.

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Chosen Solution

The backlight fuse is the IC with a white P or a white dot on it. Check continuity with a multimeter.

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I was able to locate one IC with a white Dot on it. Do you think that could be it?

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Also- What type of multimeter could be used? 12v or something else?

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If you have the macbook white unibody 2009/2010 2,26ghz or 2.4ghz yes the backlight fuse has a white dot on the top of it and is located to the upper left side of the LVDS socket. You can use any multimeter that can check continuity or resistance. Select the mode specified on the pict and put the red and black probs on each side of the fuse. Power off the machine and disconnect the AC adapter and the battery before taking the reading with the multimeter.

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Most Helpful Answer

Are you able to shine a flashlight through the lid (poor mans backlight)? If you can see an image then you know the backlight circuit is having problems. IF you don't then you need to focus on the display cable connection then check it again.

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Firstly, I really appreciate you taking time and helping me solve the problem. As you suggested - When i shined the light I was able to see the icons. I double checked the cables and everything is connected. So what does this mean if I am seeing the image/graphics on the LCD?

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Thats good news that means the GPU and the display are working. So you'll need to look at what is causing the backlight from working.

Try resetting the SMC TN on resetting SMC. Also check your display settings and the function keys to increase the backlight.

Also try running Apple Hardware Test (AHT) to see if anything shows up.

There are a few fuses that could have popped. These are SMT devices which are a bit tricky in replacing.

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Dan- As per your suggestion I reset SMC and i got some luck. Now the laptop is connected to an external monitor and I can see the display listed in system preferences (I wasnt able to see this earlier, before the reset). I increased the brightness and nothing changed. Ran the AHT and found no issues. Do you think it is something related to the fuse or it is the display cable?

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At this point I do think the fuse has blown. How are your soldering skills? This is a delicate soldering job SMT devices are not easy to solder and you don't want to damage anything else here.

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I have no prior soldering experience. I think I might need somebody to repair it for me. Do you think Apple can repair this or I should find someone else?

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aman0607 will be eternally grateful.
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