Mac Mini 2018 - dual monitor woes

GreatOldOne

macrumors member
Original poster
Jul 6, 2005
95
6
Herding Nerfs
I finally replaced my wheezing mid 2011 mini with a shiny new 2018 model. Just base spec, figured the speed bump between the old and new would be plenty for what it’s used for.

Anyway, all those new thunderbolt 3 / USB-C ports means that all of my external drives can now get plugged in without a hub, keyboard & mouse in the USB 3 ports and a monitor on HDMI... leaving one thunderbolt free. So, with that in mind, I purchased two identical Acer monitors (K222HQL). These have an HDMI, a DVI and a VGA port each.

So, monitor one, HDMI to HDMI. No problems, works like a charm.
Monitor two, not so much. I’ve tried a thunderbolt to HDMI adaptor (2 copies of the same make and model) in conjunction with a variety of HDMI cables, on both monitors. Every time I get a picture, of the correct size & resolution etc.. except it’s Pink. I’ve also tried a thunderbolt to HDMI, which I suspect is just the same sort of thing as the adaptors, just with a cable rather than female HDMI socket. Same thing.

Bothe monitors work ok on Native HDMI from the mini. They also work fine on The DVI to DisplayPort cables that connect them to my work laptop dock (which needs to use the DVI).

I’ve googled this, and seen other issues related to it on other thunderbolt 3 equipped macs, and mostly the advice seems to be check the cables, but they’re all solidly connected. And with all the “check it with this monitor and this cable combination” ive done, I think I can rule out issues with the monitors & cables. I’ve also attempted to reset the nv ram, but I don’t think I have successfully.

I suppose I could have had really bad luck and got three duff parts brand new from amazon. But it seems unlikely.

Anyway, can anyone suggest anything else?

These are the cables I’ve purchased:
https://www.amazon.co.uk/gp/product/B07CQM2ZSZ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B075V68NVR/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Do I need to get myself an “official” adaptor from Apple at a price that’s almost as much as one of the monitors iteslf? Are there any settings I can look at in the display panel in system settings? Specialmonitor profiles to, prevent the pinkness?

Thanks in advance,

Jason

[edit to add pics]
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Last edited:

inmnbob

macrumors regular
Aug 6, 2014
230
82
Chicago and Twin Cities
I think it could be the TB cables. I was using one I bought fro Amazon with my new monitor and it was causing problems and not operating as smooth as it should and messed the mouse up too. I tried the Apple TB cable and all was fixed. The Amazon cable said it was TB verified so?
 

GreatOldOne

macrumors member
Original poster
Jul 6, 2005
95
6
Herding Nerfs
Thanks. Yes, all the cables I’ve bought so far have been from Amazon and claim to be thunderbolt 3 compliant / usb 3.1. The adapters have already had a return started. Looks like the other cable will be joining them.

I’ll look into the RGB issue as well.

Puzzling that the monitor doesn’t show up on the device tree though. It shows my ancient usb to serial converter I use on my UPS. Why not the monitor? :rolleyes::)
 

Coyote2006

macrumors 6502a
Apr 16, 2006
501
229
I never save money on cheap high-end cables or adapters. I always buy them from apple. These few $ more are worth to prevent all of the problems that might/will occur. Just my experience ...
 

G4DPII

macrumors 6502
Jun 8, 2015
268
322
The pink screen is nothing to do with Cables. It's a known flaw in the OS. has been present for years. Had it on my 2014 mini from day 1.

Apple just can't be arsed to sort it out. Like so many of the niggles that are present.
 

Coyote2006

macrumors 6502a
Apr 16, 2006
501
229
So it's not possible to connect two non Thunderbolt 3 monitors to an Mac Mini due to OS problems that are 4 years old?
 

GreatOldOne

macrumors member
Original poster
Jul 6, 2005
95
6
Herding Nerfs

ct2193

macrumors newbie
Jan 15, 2009
2
0
Chicago
I do IT for a company who uses a lot of Mac computers, many of which utilize multiple monitors. One of our graphics people was recently upgraded to a 2018 Mac Mini and the experience has been miserable.

Given the constant need for multiple displays, SDCARD slot, and even a headphone jack closer the the front of the desk, we THOUGHT we would simply set them up with a USB-C dock that claims to support both Mac and multiple simultaneous displays.

While not every laptop user needs multiple displays, many of them benefit from everything else a dock does, such as a single cable for both power and connectivity. Needless to say, we've been able to justify purchasing multiple docks for our testing.

5 docks later, none of them properly support multiple monitors.
Multiple sets of USB-C / TB3 to HDMI cables later and none of them properly support multiple displays either.
We even tried a different matching pair of monitors with both the cables and the docks.

What we experience:
- Set up the workstation (2018 Mac Mini) with multiple displays.
- Initially, it works. Until you reboot.
- Sometimes the second display comes up (10 seconds later than the first one)
- Sometimes the second display never comes on. Never detects in the Mac via displays nor in About This Mac. And reboot does not work after it fails the first time.
- Unplugging both monitors and swapping them (either at the mac or at the back of the monitor) yields only the one monitor showing up. It's like it bans the second hardware ID.
- And of course, the Mac RANDOMLY chooses which monitor is #1 vs #2, despite various methods to force this. (None require editing any files)
- Mac OS 10.15 Catalina handles multiple displays (TB2 not TB3) without issue on a 2013 Mac Pro.
- Moving the cables to other USB-C ports does not change the scenario. And reversing the cables does not appear to favor either monitor over the other, like a bad monitor / bad cable should.
 
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