Partial flickering on external monitor

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Level 1

8 points

Partial flickering on external monitor

I'm using an external monitor with my 2016 MacBook Pro 15" and have noticed that a specific section of the screen will occasionally flicker and be darker than the rest of the screen for a moment. I've determined that it's not an issue with the monitor, as I've tried it on 4 different monitors and all have the same effect. I've been sending a signal to each of these monitors through USB C (not Thunderbolt 3) and have tried different ports and cables. I'm fairly certain that this is an issue with my MBP, but I have no idea what it could be.

These are photos I took of the flickers on two different monitors. The shape and location of the flickers appear to be the exact same.

MacBook Pro 15″, macOS 10.15

Posted on Sep 11, 2020 12:56 AM

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Answer 1

sterling r

Community Specialist

Sep 11, 2020 7:20 PM in response to bronzezoo

Hey bronzezoo,

If we understand, you're having an issue with the same spot flickering on an external display that is connected to your Mac. We want to help with this. It was a great idea testing with different monitors, cables and ports. This definitely helps to narrow it down. If you haven't already, take a look at the steps in the following guide for video issues: Get help with video issues on external displays connected to your Mac

Let us know how that goes.

Cheers!

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Answer 2

bronzezoo Author

Level 1

8 points

Sep 12, 2020 11:49 AM in response to rcosta887

I think you have a point. I've noticed that on all monitors, it defaults to 59.88 Hz instead of 60. This LG monitor in particular has an option for 75 Hz, but whenever I enable that the monitor alerts me that it's not the recommended setting. I can't reproduce the issue consistently, so I'll just have to wait until I see it again. I went ahead and did what you said and changed the resolution from 1440p to1080p to see if that has any effect.

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Answer 3

rcosta887

Level 4

3,604 points

Sep 12, 2020 4:34 AM in response to bronzezoo

Based on your testing I'm thinking it's an issue with the Mac trying to consistently output the signal at the resolution and refresh rate.

As a test, if you drop down the resolution does the problem go away? In display settings, if you hold down the Option key as you click on "Scaled" it will list specific resolutions you can set your external display to.

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Answer 4

bronzezoo Author

Level 1

8 points

Sep 12, 2020 11:45 AM in response to sterling r

Hi Sterling,

Thanks for the response. Your understanding of the problem is correct. I checked the website you linked, but I'm not sure any of the problems/solutions listed on that page apply to what I'm experiencing.

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Partial flickering on external monitor

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