Macbook Air m2 connected to external monitor but no input signals on the monitor

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Macbook Air m2 connected to external monitor but no input signals on the monitor

Hi, would anyone be able to help me resolve this issue please?

This has happened to me a few times and since the last time, I have not been able to use my external monitor screen on my Macbook Air M2. I could connect to the external monitor via a USB-C to HDMI cable, and my laptop actually detects and identifies the external monitor as connected, like shown in the pictures. However, as you could see, the monitor still says "Input Signal Not Found".

I know that there is nothing wrong with the cable connections or the monitor itself because they work perfectly with my windows laptop. What is wrong with the Macbook Air M2?

Kind regards,

Vannis

MacBook Air, macOS 14.4

Posted on Mar 17, 2024 4:38 AM

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Answer 1

Top-ranking reply

wilydave

Level 1

12 points

Jun 1, 2024 6:00 PM in response to Vannisastantin

Hi Vannis (and all) –

(The issue I had was M3 Mac using USBC-to-USBC to a Dell Ultrasharp monitor which also served as my hub for camera, keyboard and mouse).

I had similar issue with my M3 Mac after upgrading to Sonoma. I'm not sure if the upgrade had anything to do with it or if just unplugging and replugging the USBC monitor messed it up. Anyway, after looking all over the place, checking all the cables, trying different laptops (which by the way worked)... I bought a new shorter USBC cable that was especially for DisplayPort (DP Alt Mode).

As you probably know, not all cables are created equal. Apparently, Mx laptops are particularly sensitive when it comes to the cable. Everything I've seen says try to keep it to 1 m in length and make sure it can handle DP Alt Mode. Once I attached the new cable, it worked fine again. I wish Apple and the major monitor makers would publish better guidance on best cables to use, and how to troubleshoot this.

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Answer 2

Mar 17, 2024 5:02 AM in response to Vannisastantin

Does the monitor have multiple HDMI inputs? If it does, and a different one (than the one's that's connected) is selected, that could be causing the problem.

What is that monitor's resolution? I see that its name is HP M24f FHD. That suggests 1920x1080, as does this page on HP's site .

What is the rating on that cable? You're going to need at least a High Speed HDMI cable for 1920x1080@60Hz. Standard / Category 1 HDMI tables might only be good for a 1080i (interlaced) or 720p television set.

https://www.cablematters.com/Blog/HDMI/HDMI-cable-types-the-ultimate-guide

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Answer 3

Mar 17, 2024 5:33 AM in response to Servant of Cats

Hi,

No the monitor only has one HDMI input.

Yes the resolution is 1920x1080, I am not sure of the rating of the cable, but I am sure the cable is not the problem. Because by plugging the cable in my Lenovo Yoga laptop, it works perfectly, and the same cable has been working well on my Macbook Air M2 for the past half year until recently I used the external monitor for the new Lenovo Yoga. When I unplugged it from Lenovo Yoga and plugged it in on Macbook, it stopped working properly.

Kind regards,

Vannis

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Macbook Air m2 connected to external monitor but no input signals on the monitor

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