Technician question: black screen occasionally works after airplay (not always)

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Technician question: black screen occasionally works after airplay (not always)

So here's my question. Some time ago my 2012 Macbook Pro developed the "black screen issue." Meaning, the screen is black and the rest of the computer works. (The HDMI display ports don't output though).

I have done everything under the sun to troubleshoot this, followed every internet support rabbit hole, called Apple Care, and nothing worked. The one thing I have not done is update the OS.

I was able to work around it by getting into voiceover and airplaying it to Roku through the displays icon on the top menu bar. (Commands below for anyone who needs it).

However, here's the question:

I have noticed after months and months of this, it will intermittently and suddenly work. Right now it's playing and it's just fine. It was airplaying, and it crashed, and when I rebooted, screen came on as if it were never broken. Then next time it's closed, reboots, sometimes sleeps etc, black screen. It may be black for 6 months, then randomly comes on. Then goes out the next time.

There does not seem to be any way to replicate this, it just does it for the heck of it. The mac wants what the mac wants. Moving the screen/laptop doesn't matter. (Although it's worth mentioning that the screen does need to be propped since it's not tight anymore and goes too far back. But that doesn't seem to be the issue here).

Technicians: what kind of a problem does that point to? Just curious.

(I"ve given up troubleshooting, have tried everything short of replacing actual hardware and upgrading Mojave).

Thoughts? Thx in advance.

--Added note: The screen was just working. I plugged in the HDMI dsplay to test it. It worked momentarily, then both screens went black, and now the macbook screen is black again. I am airplaying it again which is working fine.

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DIRECTIONS FOR AIRPLAYING WHEN MAC HAS A BLACK SCREEN

Call Apple accessibilty support,

have them help you to navigate to turn on voiceover (also, turn OFF verbosity or it will drive you insane)

make sure the displays menu in the top bar shows your airplay options (i.e. your Roku)

Have them help you set up commands. Mine are:

Cmd- F5 to turn voiceover on

(Ctl Tab until voiceover tells you that you are on Finder)

Ctl-opt - MM (Menu extras)

Ctl - opt - right arrow : Navigate to the right until you hear it say "displays menu"

Ctl - opt - spacebar to select the displays menu

Ctl - opt - down arrow until you get to your desired airplay (Mine is Roku streaming stick)

Ctl - opt - spacebar to select

You should now see your display on the external TV.

Cmd - F5 to turn voiceover off

This has worked fine and allowed me to continue to use my old macbook. I hope this helps someone out there.

Posted on Aug 9, 2023 10:16 AM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

140,255 points

Sep 15, 2023 8:11 AM in response to Editgrrl1

You have it mostly right, but not the conclusions.

When you connect an external display OR run Google Chrome, the maximum graphics power of the (more capable) Discrete Graphics processor is used for ALL hardware-accelerated displays -- except if you want an AirPlay display, which can only be provided by specialized compression hardware in the Integrated intel graphics processor.

Your symptoms suggest that Integrated Graphics may be perfectly fine.

The Discrete graphics is NOT working fine.

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as an aside, there was a work-around for certain models, if you could decide to NEVER connect a hardware-accelerated external display or use Chrome, you could patch out the Discrete graphics processor, and you could continue to use the damaged Mac for most purposes. One side effect was that with the Discrete processor patched out, your Mac would never wake from sleep, so you must also avoid sleeping your Mac.

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Answer 2

Sep 13, 2023 8:47 AM in response to Editgrrl1

AirPlay paradoxically uses features built into the integrated intel graphics chip, and is not available otherwise.

AirPlay captures the screen, strongly compresses the data, and sends out occasional screen-update bursts, rather than the traditional 60 Hz brute force repainting of the entire screen. AirPlay has never been suitable for Full-motion Video at peak resolutions and top refresh rates.

Since it uses a completely separate mechanism, you are finding it is often working while the fully hardware-accelerated Discrete graphics chip is flaky.

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Answer 3

Sep 16, 2023 3:47 PM in response to Editgrrl1

Your discrete Graphics chip is flaky.

You can't reliably use Chrome (because it immediately demands the HIGHEST graphics available.)

You can't reliably use an external display (because connecting one immediately sets all displays to use Discrete graphics chip.)

if you want to do those things, your screens will go black and stop working form time-to-time.

You should be thinking about a more capable computer.

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Answer 4

Aug 11, 2023 6:42 AM in response to Editgrrl1

supporting an external display sets your Mac to use ONLY the Discrete GPU, the one that is flaky.

leroydouglas diagnosis is spot-on.

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Answer 5

Aug 9, 2023 1:13 PM in response to Editgrrl1

Editgrrl1 wrote:

So here's my question. Some time ago my 2012 Macbook Pro developed the "black screen issue." Meaning, the screen is black and the rest of the computer works. (The HDMI display ports don't output though).

If an external monitor does not work you can suspect GPU failure.

see vintage and obsolete:

Obtaining service for your Apple product after an expired warranty - Apple Support

Obtaining service for your Apple product after an expired ...

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Answer 6

Editgrrl1 Author

Level 1

21 points

Aug 10, 2023 3:05 PM in response to leroydouglas

Thank you. I am assuming that would hold true even though the external worked briefly when the screen went on? Only for about 30 seconds though, then they both went off.

Is that 100% what could be wrong or are there other things that might cause simiilar symptoms? For instance, some corruption in the settings somewhere that might be reset somehow? Thank you

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Answer 7

Editgrrl1 Author

Level 1

21 points

Sep 13, 2023 7:50 AM in response to Editgrrl1

I am airplaying right now, and it says that the Intel Graphcs 4000 is in use. (The laptop screen is black)

Intel HD Graphics 4000:

Chipset Model: Intel HD Graphics 4000

Type: GPU

Bus: Built-In

VRAM (Dynamic, Max): 1536 MB

Vendor: Intel

Device ID: 0x0166

Revision ID: 0x0009

Automatic Graphics Switching: Supported

gMux Version: 3.2.19 [3.2.8]

Metal: Supported, feature set macOS GPUFamily1 v4

Displays:

Color LCD:

Display Type: Built-In Retina LCD

Resolution: 2880 x 1800 Retina

Framebuffer Depth: 24-Bit Color (ARGB8888)

Main Display: Yes

Mirror: On

Mirror Status: Master Mirror

Online: Yes

Rotation: Supported

Automatically Adjust Brightness: No

Roku Streaming Stick :

Resolution: 1440 x 900 (Widescreen eXtended Graphics Array Plus)

UI Looks like: 1440 x 900 @ 60 Hz

Framebuffer Depth: 24-Bit Color (ARGB8888)

Mirror Status: Mirroring

Automatically Adjust Brightness: No

Virtual Device: Yes

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Answer 8

Editgrrl1 Author

Level 1

21 points

Sep 13, 2023 7:39 AM in response to Grant Bennet-Alder

Thank you,

Is there anything I can do other than flat-out replacement of it? That's the added graphics card, right? Can I work around it somehow? With the other graphics processor? To at least get the main screen working without the external display, so I can use it wthout airplaying?

Also something I don't understand is why the (laptop) screen woudl randomly work., then not. Except "flaky" makes sense as an explanation. If the graphics card for the external display is bad, does this mean my other one is bad also? Would they both go at once?

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Answer 9

Editgrrl1 Author

Level 1

21 points

Sep 14, 2023 8:35 PM in response to Grant Bennet-Alder

Thank you for that. I have a question. So am I understanding correctly that it has two graphics processors?

1) is integrated, this Graphics 4000, and

2) is additional (discrete?) my nvidia card?

I probably have this completely wrong so forgive me.

Then, the airplay is working off the integrated?

So the integrated is bad, giving me the black screen, but not bad enough that airplay won't work? And "flaky," meaning it decides to just wake up once in awhile?

And #2 card is bad as well, since it won't go to an external monitor?

So both are shot? What would cause them both to die at the same time?

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Answer 10

Editgrrl1 Author

Level 1

21 points

Sep 15, 2023 11:31 AM in response to Grant Bennet-Alder

Interesting.

So earlier it woudln't airplay. I hard-rebooted it. Now the screen works. I am writing this in Chrome.

Will see what happens when I go to CNN or something else that uses a lot of resources, like Accuweather.

Here's the card info if it matters.

NVIDIA GeForce GT 650M:

Chipset Model: NVIDIA GeForce GT 650M

Type: GPU

Bus: PCIe

PCIe Lane Width: x8

VRAM (Total): 1 GB

Vendor: NVIDIA (0x10de)

Device ID: 0x0fd5

Revision ID: 0x00a2

ROM Revision: 3688

Automatic Graphics Switching: Supported

gMux Version: 3.2.19 [3.2.8]

Metal: Supported, feature set macOS GPUFamily1 v4

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Answer 11

Editgrrl1 Author

Level 1

21 points

Sep 16, 2023 2:21 PM in response to Editgrrl1

Ok all. Thanks for your help. So here's what's happening now.

When i hard-reboot it with the power key, the laptop screen comes on and works. Then occasionally goes black during certain tasks.

Is it possibly my graphics cards are ok, and maybe the drivers are messed up? How would I reset this to test? Thank you

Here's what went before:

I didn't see gfxcardstatus in the menu bar, so reinstalled it (then it showed it twice).

At first I was unable to select "integrated." (grayed out).

Then I was able to, but it went black. (Crashed and shut down? Don't recall)

Would not airplay after that. However, that's when rebooting it started making the screen work.

Now it airplays fine.

It has gone back to black a couple of times while using Chrome and once while opening an email in Firefox. It's working fine right now as I'm writing this.

It did crash (shut down? not sure) while closing Photoshop, although it ran it fine and only crashed when quitting.

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Answer 12

Editgrrl1 Author

Level 1

21 points

Oct 6, 2023 4:49 PM in response to Editgrrl1

THank you so much everyone. It looks like I inadvertantly marked my own post as best answer! Must have been very tired. Am not sure how to undo that.

Anyway, so appreciative of all of your answers and explanations. At least now I understand what the problem is. I've been able to reboot and sometimes get a screen for a few minutes but mostly ahve to airplay.

I actually do have a more capable computer but this has been an important second. I might have to look at having it repaired. Other than this one problem it's been pretty decent.

Thanks again

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Answer 13

Editgrrl1 Author

Level 1

21 points

Oct 6, 2023 4:44 PM in response to Editgrrl1

Oops! Didn't mean to mark this!

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Technician question: black screen occasionally works after airplay (not always)

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