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

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Why doesn't my screen light

Hi there guys, long time lurker first time poster here. I have just purchased a used MacBook Pro 13" Mid 2010 MC375LL 2.66 GHz Logic Board 661-5560 820-2879-B. As the heatsink bracket is different from the 2.26ghz models i purchased one of them as well. Okay... My Macbook Pro 13 was a late 2009 version until I purchased the above Logicboard. I am a PC technition and mainly deal with Desktops and notebooks so i am very comfortable working on pretty much anything.

I have installed the replacement Logic board 2.66 into the 2009 unibody with the heatsink. Everything was a walk in the park. As i have gone to boot it up, all i get is startup sound and the darkscreen, now i can see the login info. The green shift key light works. but nothing... Now i thought the screen might be gone as well, so i removed another screen off a working Macbook pro 13 (Late 2009) and plugged it into this model. I am still experiencing the same problem. I have already done a PRAM and SMC reset. Guys... what could be the problem? Does the unibody need to be replaced for 2010 version as well. Please help me with this dilemma!!!!!



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The LVDS/data video cable is the same for the models you speak of. The voltage for the LED backlight runs up it. There is what Apple calls a LED driver board, that does not contain the LED driver, it amounts to a 5v switch that allows the voltage from the LVDS cable to be used by the LED backlight - since it really doesn't carry any current I'd say it has 100 year life span. The actual LED driver is on the logic board. Most of the problems with the backlight on these stems from the logic board. You should see 12v - 24v (depending on the brightness setting) off the diode where the arrow says measure backlight voltage. If you see no voltage there check for continuity on the fuse, which is labeled. The fuse is very small, a 0402 package, 1mm in length. If the problem isn't there or one of the cables you are dead in the water without the right test equipment.

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Thanks for that ABCellars, will check it and get back to you....


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