User profile for user: Jerser25
Jerser25 Author
User level: Level 1
16 points

iMac facing Black Screen issue after waking from Sleep

Hi. Im using a dual monitor MAC. my Primary is a Thunderbolt Display & the Secondary is a Built-in Retina Display. Its a second hand system that I acquired months back. OS is Monterey. Processor is a 3.2 GHz QuadCore Intel i5. Graphics is AMD Radeon R9 M380 2GB.

the issue just started last week. the Primary wont come up from sleep mode. I will have to restart the computer every time to bring it to work.

I have tried to push the powerbutton of my Secondary for 15sec until it shuts down & waited for a min. before turning it on. done it several times, still the same.

Tried resetting the SCM twice already to no avail.

Thought it might be the display cable, but it looks ok. & logically, not sure if you all will agree to me, if its the cable it will not come up even if I restart it.

One thing that I have noticed, if it goes to sleep only for a short while, both screen will come up if I wake it up.

But if I let it sleep for more than 30mins, the issue with the primary will reoccur.

Please bare with me for I just started using MAC when I got this system. your suggestions will be appreciated. Thanks in advance.


[Re-Titled By Moderator]

iMac 27″, macOS 12.7

Posted on Jan 2, 2025 8:19 PM

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User profile for user: den.thed
den.thed
User level: Level 10
94,746 points

Posted on Jan 2, 2025 10:29 PM

Jerser25 wrote:

One thing that I have noticed, if it goes to sleep only for a short while, both screen will come up if I wake it up.
But if I let it sleep for more than 30mins, the issue with the primary will reoccur.


+1 This sounds like one of several issues caused by using full computer sleep mode that may never be fixed. Basically the external display connection is lost when the iMac goes into full computer sleeps mode and does not reconnect when the iMac re-wakes from full computer sleep mode.


As a test:

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the iMac On and only allow the displays to turn Off

Do not manually Sleep from the Apple Drop Down menu

Only Shut Down when away for a day or more

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User profile for user: den.thed
den.thed
User level: Level 10
94,746 points

Jan 2, 2025 10:29 PM in response to Jerser25

Jerser25 wrote:

One thing that I have noticed, if it goes to sleep only for a short while, both screen will come up if I wake it up.
But if I let it sleep for more than 30mins, the issue with the primary will reoccur.


+1 This sounds like one of several issues caused by using full computer sleep mode that may never be fixed. Basically the external display connection is lost when the iMac goes into full computer sleeps mode and does not reconnect when the iMac re-wakes from full computer sleep mode.


As a test:

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the iMac On and only allow the displays to turn Off

Do not manually Sleep from the Apple Drop Down menu

Only Shut Down when away for a day or more

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User profile for user: Jerser25
Jerser25 Author
User level: Level 1
16 points

Jan 3, 2025 9:59 AM in response to den.thed

Thanks for all the suggestions. Greatly appreciate it. I was able to do the Energy Saver setting which is ''Prevent your MAC from Automatically...". I left it that way before going to bed last night. After I got up this morning, I was able to bring up both monitors. That look to have worked out. The only drawback I think it the non-MAC mechanical RGB keyboard, which is connected with a wire to the Retina Monitor, is lit-up all the time. I guess I will have to disconnect that every time to work around it.


One thing though. This is the only thing that I can not perform. The 'Lock Screen'' option is nowhere to be found. When I try to search for it, it just directs me to Energy Saver or Security Privacy. I guess my OS version does have that.

Still, thanks again for the help. I can be relieved that I can enjoy using this setup which I just finished paying LoL!

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iMac facing Black Screen issue after waking from Sleep

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