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MacBook A1278 Screen intermittently dark

My MacBook A1278 Screen intermittently goes dark. I can see that the display is still working with a flashlight. If I press the brightness buttons I can see that the increase/decrease bar is working.

- This model does not have an inverter as it is LED lit

- Because I can see the display working, I assume that the logic board and drivers are good.

- I am guessing that the intermittent part eliminates a problem with the WLED fuse on the on the logic board not supplying power to the LED, and perhaps the LED itself.

So???

LVDS cable??

Other possibility??

If cable, is this replaceable?

Answered! View the answer I have this problem too

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The LCD its self is likely OK here. The logic board has the power circuity for the LED backlight and it could need repair.

But, first lets see if the data cable is OK. Does the backlight wink on and off when you tilt the lid or press on the display? If it does then you likely have a bad cable. Review this IFIXIT guide Replacing MacBook Unibody Model A1278 LCD Panel In this case we need to get to the cable on the LCD and logic board to replace it

From the Apps store download Temperature Gauge or some other like monitoring program. With it running see what the temp of the display is when the backlight goes out. Then try lowering the screen brightness does the backlight stay working longer and is the temp lower? If it is then you may have a bad display (the LED backlight part of it).

If it winks out with no movement at any brightness then your problem is on the logic board and you will need to review the backlight power circuit. You likely have a cold solder joint on one of the power FET's.

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Wow! What thoughtful, detailed, and considered advice Dan! I doubt I could get better even if I paid for it.

You have listened to all the parts of my question, then,

given me a flow chart for proceeding with diagnostics, then,

handed me the tools and references I need...............

Even if I never get to the bottom of the problem, your answer makes me feel like Lois Lane being pick out of the air by Superman just before she was about to hit the ground! My mac may yet get another chance at life!..............

The troubled Macbook in question is unavailable to me for the next three or more weeks, but with this advice, I can hardly wait to get back at it.......... Thank you so much Dan.

http://www.wallpapergate.com/wallpaper18...

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Very cute reply! Never thought I would be confused for Superman! ;-} Let us know how it goes when you get a chance to fix your system. Good Luck!

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In step 9 of the LCD display iFixit report for the A1278, I removed and then used tuner cleaner spray on the cable connector and the cable end going from the motherboard to inverter/display cable. It seems to have fixed the issue. Sure beat tearing the display apart!

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Be careful here! Tuner cleaners have oils in them. Don't spray it use a Q-Tip (cotton swab) to apply after moist'ing it with the spray only on the contacts (a little goes a long way here). The oil attracts dust and can cause signal errors in micro electronics as the signals are much lower that what the old transistor or vacuum tube radios had. So you don't want it going all over the place.

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might be the sleep sensor problems...just check the connection...!

id tried this link,and fixed (just the connection loose)

MacBook Unibody Model A1278 Hard Drive Bracket with Sleep Sensor Replacement

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Kent Green will be eternally grateful.
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