Monitor (M27U) turning black randomly

Ryan F · February 23

I have my Gigabyte M27U connected to my 16" MacBook Pro 2021 with a single USB-C cable carrying display, keyboard/mouse passthrough, and ~18W passthrough charging. At seemingly random times (I cannot figure out a pattern, sometimes within minutes of plugging it in, sometimes after hours), one of two things happens: 1) The M27U will go black, however it does not disconnect. The charging/keyboard/mouse passthrough still works and I can still move the mouse over to that area, I just can't see it. So the computer thinks there is still a second display. 2) The connection completely cuts out and disconnected everything, then reconnects on its own and is back up and running shortly after.

This happened with the original and the replacement Newegg sent me after I complained about this issue, so I don't think it's a broken unit. This is extremely disappointing because I love the monitor otherwise.

Here is some troubleshooting I have tried:

- This issue still happens when the USB-C cable is connected to any port on the laptop.

- This issue doesn't happen when I use any other type of display connector (HDMI, DisplayPort).

- When I connect video separately and just use USB-C for keyboard/mouse/charging, the USB-C connection still cuts out randomly but video does not.

- It does not seem like this issue happens when connected to a windows computer, although there is no way to confirm this for sure (I just had it connected for a while and it didn't happen).

I cannot update the firmware because it seems like that requires the OSD sidekick, which exists for the M27Q and the M28U on Gigabyte's site but not the M27U??

Does anyone have any idea what could be causing this and if there is anything I can do about it? And if not, do you think the same problem would happen with the M28U? I am thinking about switching it out for that one.

Biohazard777 · February 23

12 minutes ago, Ryan F said:

...
- This issue doesn't happen when I use any other type of display connector (HDMI, DisplayPort).

- When I connect video separately and just use USB-C for keyboard/mouse/charging, the USB-C connection still cuts out randomly but video does not.

...
Does anyone have any idea what could be causing this and if there is anything I can do about it?

I haven't had any issues with M27Q and M1 Mac Mini.
Granted it is a different monitor model and I'm not using passthrough charging in my setup.
But I did fork over 40-50$ (can't remember exactly) for a 0.8m Apple Thunderbolt 3 (USB-C) Cable ,

after reading many Reddit posts how it is a pure lottery with other cables.

Ryan F · March 26

On 2/23/2024 at 3:28 PM, Biohazard777 said:

I'm not using passthrough charging in my setup.

This inspired me to try not using passthrough charging and instead plugging in external power but having everything else still go through the monitor and it has been working beautifully ever since, not a single issue! I have no idea what the problem was, whether it was the cable or a software bug between Apple silicon computers and this specific monitor or something else, but it seems it is caused by passthrough charging, and external power solves it. Not a big loss because I would have had to set up external charging anyway if I ever wanted more than 18W. Thank you very much, I am so glad I don't have to return this monitor!