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Display backlighting does not work

I have a penryn (early 2008) 2.5 ghz 15" MacBook Pro that I was replacing the rear bezel on. Very simple and straightforward stuff, but now my display backlighting doesn't work, making it nearly impossible to display anything. Nothing seems to be wrong with my assembly, and I'm at a loss as to what could be wrong. Obviously it was something I did, as it operated perfectly before.

Does anyone have any experience with this problem, or have any ideas of things to check?

<Edit>

My LED driver board does not have any outward signs of damage, and I don't think I touched it at all with my spudger, but seeing as its the LED driver board and its in a rather exposed spot, I'm inclined to suspect it. Is there any other trouble spots I should be thinking about?

Answer this question I have this problem too

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The inverter cable seems fine, insulation is intact, all connectors are secure and free from damage, I also replaced the LED driver board. No change in status, the display still has no backlighting. no bright white background on startup (which if I remember right, should be bright regardless of brightness setting). after booting up my brightness is set at max.

obviously its a possibility that it could be the display itself, is there a way to check that short of putting the display in another A1260 MBP?

Could it be on the end of the left I/O board (seems logical possibility as the inverter cable plugs in there)

My multi meter is not small enough, but I will try to check the inverter cable, even though it seems to be in perfect shape.

Thanks for the help, any further advice would be helpful.

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6 Answers

Most Helpful Answer

Check the inverter cable carefully from the logic board to the LCD for proper connection and security. Begin at step 14. Ralph

MacBook Pro 15" Core 2 Duo Models A1226 and A1260 Rear Display Bezel Replacement

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Looking at the teardown I'm inclined to agree with you. If the inverter cable is secure it may be the LED driver board. Ralph

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The inverter cable is most definitely secure, and replacement of the LED driver board has led to no change. An IT friend of mine and I got our heads together and looked at some possibilities, and decided that the culprit is probably the CCFL. I should know one way or another tomorrow.

-Gabe

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I just went through this same problem myself, and it ended up being a faulty left I/O board. I'm not sure why that would have failed, as all I did was disconnect the LED driver board cable from it, then reconnect after I put it back together, but I got a replacement I/O board off eBay and my backlight is back at last.

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Funny, I'm having an almost identical problem. I was replacing the LCD on a MacBook Pro 15" 2.2 ghz machine. The new LCD worked fine - or actually, it took a restart together with resetting PRAM for the backlight to work. I used it for a number of days with the new screen perched a bit precariously outside the bezel. After the screen accidentally tipped and disconnected from the display cable it no longer is backlit, though still displays the image ok. The old, broken screen also fails to be backlit. I was hoping resetting PRAM would help this time, too, but it hasn't. The inverter board is not evidently damaged: the two connections are secure to the inverter board and to the motherboard, and a replacement inverter board has failed to solve the problem for either screen. An external monitor works fine, suggesting no issues with the graphics card. My guess is that it's *not* the CCFL, because both screens show the same problem.

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Just an idea, I have just had the same problem after changing the screen display itself, picture yes but no backlight.Pram reset didnt help and its only one connector.Try flipping back the protective white sheet of plastic on the back of the screen which covers the circuit board.Choose the area which exposes the small connector. This one contains the leads to the bulb itself.Flip it open and close it again.this seemed to solve the problem and the backlight came on. Just an idea.

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I seem to have the same problem..after replacing the screen with a wrong one there is no backlight anymore. I have now received the right lcd which works ,(picture is good held against light source)

So I think that the wrong screen must have shot the power on the i/o board.I am only meassuring around 2 volts at the led inverter/regulator board.Does anyone know how much power the led board runs off.

I have just received a new batch of inverters but still no backlight. I have just ordered an i/o board.

This repair job is starting to worry me.

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I got the same problem as many of you when we replace the screen in the Mac Book Pro A1226.

I just replace the screen on my Mac Book A1226 Santa Rosa, I installed the same model and serie of my old screen and I got the same problem. The backlight of the screen is not working. With a flash light, I can see that the operating system is working in my comp and it goes into the internet but the imagen is too dark arround only for 15% of backlight.

I can guess that the led driver board is the problem but I do not want to star buying things that could not be. Just want to wait to see if anyone solve this problem to help us to resolve the same problem we had.

Helpfully, someone will solve the problem soon and share the information with us of what he/she did to solve the problem.

thanks.

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gabemasiulis will be eternally grateful.
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