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Early 2011 model, A1278 / 2.3 GHz i5 or 2.7 GHz i7 processor.

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Screen backlight shuts off intermittently

I know there are tons of questions/answers on this forum relating to this topic, but after reading through most of them, the symptoms don't fully line up with mine. My apologies if this is covered elsewhere, I'm hoping someone can lead me in the right position.

Yesterday, my screen shut off out of nowhere. Keyboard was still lit. The computer was still running because I was listening to music and that didn't stop. When I held a flashlight to the back of the monitor/apple, I can see my whole desktop. I can even navigate around and restart the computer if I have enough patience.

On occasion, closing the laptop and reopening it, will bring the screen back up.

Wiggling the screen back and forth, does nothing. It's not flickering like there's a short in the cable.

Restarting the computer doesn't seem to bring the screen back to life.

I just took the bottom cover of the laptop off. I pressed on most of the connectors/shoes to make sure that everything was seated properly. Once I put the case back together and opened the lid, the screen worked for about 30 minutes before going out again.

If anyone can lead me to a post that answers or helps diagnose this problem, I would be so greatly appreciated. Thank you in advance.

Answer this question I have this problem too

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One additionally thought... I am on 10.12.6

Is there an issue going around where the power management of the screen gets in the way of the back light coming back up?

I have gone into my settings and disabled the screen being dimmed or put to sleep. It's been up and running now for almost 1 hour.

I have tried moving the screen open and almost closed, open and almost closed, and I can't get the screen to now black out.

OS problem or coincidence?

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5 Answers

Most Helpful Answer

Unplug the battery indicator and see if it has the same issue. This has the hall effect sensor on it, which detects when the screen is closed.

If this is faulty, or has minor corrosion, it can randomly drop the voltage of SMC_LID_L, which will cause the screen to lose backlight, since it thinks the lid is shut.

If it is working fine with this disconnected, replace it.

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Hey Reece, I do appreciate the comment. Unfortunately, this didn't work. I disconnected the battery indictor tab with sensor, and when powering the computer back up, the screen lit up but ended up going black while logging into the system.

I did a hard shut down. Closed the screen, reopened the screen, rebooted and so far it's working. I'm trying to troubleshoot it now with the screen at certain angles for prolonged periods of time, with the laptop stationary. Maybe there is a short in a cable and with the screen at certain angles, it's losing connection?

On another note, my battery is completely shot. Without power supply, it may only last 1 hour. I recently installed Tech Tool 9.5.1 and it's constantly giving me battery errors. This screen issue begun around the same time frame that I installed Tech Tool. Do you think there is any correlation between the screen going dark, the battery being completely shot, and Tech Tool? The battery has been shot for at least a year though with no issues until now.

Thanks for any additional help you may have.

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I have the same exact symptoms on my mid 2014 mbp 13”. Did you fix your problem yet?

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Not an answer, sorry Zak. Just another looking for one.

I have a secondhand 2015 macbook pro. Every now and again, randomly about once a month or once every two months, the screen will go black while working on it. I’ve found that if I lift the whole thing off the table, and gently wave it, it will come back on to the log in screen. I just type my passcode and I’m back in.

Sometimes, just setting it back on the table causes it to switch off again.

The seller had had a complete Apple screen replacement just before selling it. The screen and topcase was pristine, but there were a few scratches on the bottom of the case. So I believed him. And he later provided written evidence of the official repair.

Could the Apple techs have put something back loose when they fixed it? I’ve tried resetting the nvram etc as advised by Apple.

Apart from this random, infrequent, and impossible to replicate on demand, issue I love the machine. I’d be grateful for any help or for a link to an already posted answer.

Cheers

Steve

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I would try looking at the LVDS cable and the port on the logic board.

Failing this it you have a multimeter then you can locate the backlight chipset and test that.

You should be able to find a schematic on the web somewhere now.

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I think I’ve discovered the cause of my problem and it’s a bit embarrassing. I have a brown faux leather sleeve with magnetic closure. When I set the Mac on that, sometimes, if it’s lined up wrongly then the magnets tell the Mac that the lid has closed and they switch off the screen!

This won’t be the same issue with everyone, but I guess there’ll be other donkeys out there like me, who were causing the problem themselves, unknowingly. If I was an apple tech I’d be asking if there was anything magnetic around which could be the issue. So, I hope my experience helps some people out there.

Cheers

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Zak Jordan will be eternally grateful.
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