Issue: 2018 Mac mini - Problem getting third monitor to work

[Moolani]

Just got my new 2018 Mac mini (i7, 16GB, 512GB) to replace my 2012 Mac mini Quad which was starting to show its age. I have 3 old Dell U2312HM (Ultrasharp 1080p monitors, VGA/DVI/DP) which I want to keep - was really looking forward to finally being able to use three monitors as the old Mini could only use two.

Hooked two up with USB-C to DisplayPort cables, worked beautifully. But I can't get the last one to work at all. Since the monitor doesn't have a HDMI input, I have tried a HDMI -> DVI, HDMI -> Displayport and even a HDMI -> VGA cable - none of them work. Tried the HDMI port on all three monitors, still no luck. Then I did some research and found out about HDMI 2.0 vs 1.4 incompatibility, HDMI and DP not being bi-directional, or even HDCP being possible causes.

To rule out the HDMI port on the Mini, I did try hooking the Mini to a TV through just HDMI - works fine with a 6' cable, but didn't work with a 25' cable.

Any ideas? Would hate to have to replace my monitors since they work fine and I like the triple monitor set up. Thanks!

 

[FreakinEurekan]

So, even with just one display attached you can't get it to work with HDMI? I don't have a 2018 mini yet and don't have that exact Dell monitor. But in general, I have used this cable with multiple 2014 Minis and multiple displays: Link: http://a.co/d/jdq4JdE

 

[DesertSurfer]

This isn't going to help (sorry) but I'm having the opposite problem. My Asus PB278Q 27" works fine with my 2018 mini (same config as OP) using HDMI, but not with USB C to Display Port. It's the same Display Port input I used with my 2012 mini, so I'm puzzled. I would like to use Display port for this monitor so I can use HDMI for my TV. Any ideas?

 

[F-Train]

This isn't going to help (sorry) but I'm having the opposite problem. My Asus PB278Q 27" works fine with my 2018 mini (same config as OP) using HDMI, but not with USB C to Display Port. It's the same Display Port input I used with my 2012 mini, so I'm puzzled. I would like to use Display port for this monitor so I can use HDMI for my TV. Any ideas?

You don't mention how you are going from USB-C to DisplayPort, so I don't know if this will help. From the DisplayPort site, at https://www.displayport.org/faq/#tab-displayport-over-usb-c:

What is the best way to connect a DisplayPort over USB-C video Source device to a display that uses a standard DisplayPort receptacle?
It is preferable to use a USB-C to DisplayPort adapter cable, and it is best to use a DP certified adapter cable. This cable has a USB-C plug on one end, and a DisplayPort plug on the other end (either a mini-DP or standard DP plug). The DisplayPort over USB-C Standard was designed to accommodate such adapter cable. While there are USB-C to DisplayPort receptacle adapters on the market which enable the use of a standard DisplayPort cable (one with a DisplayPort plug on both ends), use of such adapter is not recommended because it may result in poor picture quality, intermittent operation, or no video display.
​

 

[FreakinEurekan]

This isn't going to help (sorry) but I'm having the opposite problem. My Asus PB278Q 27" works fine with my 2018 mini (same config as OP) using HDMI, but not with USB C to Display Port. It's the same Display Port input I used with my 2012 mini, so I'm puzzled. I would like to use Display port for this monitor so I can use HDMI for my TV. Any ideas?

I agree with F-Train, don't try to use an "Adapter". A single cable, USB-C to DisplayPort should take care of it such as https://www.apple.com/shop/product/HLR62ZM/A/

 

[DesertSurfer]

You don't mention how you are going from USB-C to DisplayPort, so I don't know if this will help. From the DisplayPort site, at https://www.displayport.org/faq/#tab-displayport-over-usb-c:

What is the best way to connect a DisplayPort over USB-C video Source device to a display that uses a standard DisplayPort receptacle?
It is preferable to use a USB-C to DisplayPort adapter cable, and it is best to use a DP certified adapter cable. This cable has a USB-C plug on one end, and a DisplayPort plug on the other end (either a mini-DP or standard DP plug). The DisplayPort over USB-C Standard was designed to accommodate such adapter cable. While there are USB-C to DisplayPort receptacle adapters on the market which enable the use of a standard DisplayPort cable (one with a DisplayPort plug on both ends), use of such adapter is not recommended because it may result in poor picture quality, intermittent operation, or no video display.
​

Thanks. This is the cable I used to connect the 2018 mini to my Asus monitor:

https://www.amazon.com/gp/product/B075V27G2R?ref_=pe_1811570_136791410_E_Asin_Title

I thought it would work, but no luck. I rechecked the port on the monitor by hooking up my 2012 mini with it's old mini display port to display port cable, and it works fine, so the monitor and the port are ok. Either it's the USB C to Display Port cable (which I'm returning), or it's something with the mini. I tried two of the USB C/Thunderbolt ports, didn't work with either. Rebooted with only the USB C to Display Port cable attached, and there was no signal to the monitor. When I reconnected the HDMI cable it worked fine.

 

[FreakinEurekan]

Theoretically that cable looks fine, but it's not certified (Moshi is). I've had a lot of issues with cheap DisplayPort cables causing me ALL kinds of trouble, once I decided to only buy "Certified" my problems magically disappeared. I'd send it back and get one with DP certification.

 

[DesertSurfer]

Theoretically that cable looks fine, but it's not certified (Moshi is). I've had a lot of issues with cheap DisplayPort cables causing me ALL kinds of trouble, once I decided to only buy "Certified" my problems magically disappeared. I'd send it back and get one with DP certification.

That is my next move. I was hoping not to spend $50 on a cable, but a cheap one doesn't save anything if it doesn't work! I will report back once I have the Moshi cable, which may not be until next week.

 

[F-Train]

That is my next move. I was hoping not to spend $50 on a cable, but a cheap one doesn't save anything if it doesn't work! I will report back once I have the Moshi cable, which may not be until next week.

What did the DisplayPort FAQ say? Oh, yeah:

"it is best to use a DP certified adapter cable"
​

Of course, they do have kind of a vested interest. Let's hope this fancy-shmancey Moshi cable works

If you order from Moshi direct, you get about a $2.50 credit on checkout, no tax and free shipping. Yes, there's a reason I know. I swallowed hard.

 

[rmdeluca]

Just got my new 2018 Mac mini (i7, 16GB, 512GB) to replace my 2012 Mac mini Quad which was starting to show its age. I have 3 old Dell U2312HM (Ultrasharp 1080p monitors, VGA/DVI/DP) which I want to keep - was really looking forward to finally being able to use three monitors as the old Mini could only use two.

Hooked two up with USB-C to DisplayPort cables, worked beautifully. But I can't get the last one to work at all. Since the monitor doesn't have a HDMI input, I have tried a HDMI -> DVI, HDMI -> Displayport and even a HDMI -> VGA cable - none of them work. Tried the HDMI port on all three monitors, still no luck. Then I did some research and found out about HDMI 2.0 vs 1.4 incompatibility, HDMI and DP not being bi-directional, or even HDCP being possible causes.

To rule out the HDMI port on the Mini, I did try hooking the Mini to a TV through just HDMI - works fine with a 6' cable, but didn't work with a 25' cable.

Any ideas? Would hate to have to replace my monitors since they work fine and I like the triple monitor set up. Thanks!

Part of the problem you're having is the 2018 Mini only has three DP links, but one of them is dedicated to the HDMI port. So you need to get your third video signal from the HDMI port. Although dual-mode DP outputs can convert to HDMI with a plain adapter, the reverse is not possible because HDMI signaling is not the same as DP and HDMI isn't designed to do this.

I see two options:

1) Try an active HDMI to DP converter (not adapter) that actually converts the HDMI to DP, such as:

https://www.amazon.com/StarTech-com-HDMI-DisplayPort-Converter-Adapter/dp/B0144NS4Z6

2) Get an eGPU and drive all three monitors from it. For instance:

https://www.amazon.com/Sonnet-Breakaway-Bundle-Sapphire-GPU-350W-TB3DEK/dp/B077K8KNDS

I'm highly confident #2 will work (and is still cheaper than getting all new monitors). #1 is a maybe, but much more likely to work than using an HDMI to DP or HDMI to DVI-D adapter. I'm not surprised that HDMI to VGA didn't work because the HDMI port in the Mini almost certainly doesn't have support for analog displays (it would need a RAMDAC).

 

[DesertSurfer]

Part of the problem you're having is the 2018 Mini only has three DP links, but one of them is dedicated to the HDMI port. So you need to get your third video signal from the HDMI port.

I see two options:

1) Try an active HDMI to DP converter (not adapter) that actually converts the HDMI to DP, such as:

https://www.amazon.com/StarTech-com-HDMI-DisplayPort-Converter-Adapter/dp/B0144NS4Z6

2) Get an eGPU and drive all three monitors from it. For instance:

https://www.amazon.com/Sonnet-Breakaway-Bundle-Sapphire-GPU-350W-TB3DEK/dp/B077K8KNDS

I'm highly confident #2 will work (and is still cheaper than getting all new monitors). #1 is a maybe, but much more likely to work than using an HDMI to DP or HDMI to DVI-D adapter. I'm not surprised that HDMI to VGA didn't work because the HDMI port in the Mini almost certainly doesn't have support for analog displays (it would need a RAMDAC).

That Sonnet bundle looks good. I wonder if 350 watts is enough for a beefy Nvidia card?

 

[F-Train]

That Sonnet bundle looks good. I wonder if 350 watts is enough for a beefy Nvidia card?

You might also look at the new Sapphire enclosure and bundles. Link here: https://forums.macrumors.com/threads/external-gpu-egpu-resources.2154653/page-9#post-26871723

The street price for the enclosure (Amazon) is US$260. I haven't seen a street price for the bundles.

 

[rmdeluca]

That Sonnet bundle looks good. I wonder if 350 watts is enough for a beefy Nvidia card?

Eh, how beefy? I wouldn't put more than a GTX 1080 or RTX 2080 in that 350W enclosure. If you don't overclock, a 1080Ti would also probably work.

 

[Moolani]

Part of the problem you're having is the 2018 Mini only has three DP links, but one of them is dedicated to the HDMI port. So you need to get your third video signal from the HDMI port. Although dual-mode DP outputs can convert to HDMI with a plain adapter, the reverse is not possible because HDMI signaling is not the same as DP and HDMI isn't designed to do this.

I see two options:

1) Try an active HDMI to DP converter (not adapter) that actually converts the HDMI to DP, such as:

https://www.amazon.com/StarTech-com-HDMI-DisplayPort-Converter-Adapter/dp/B0144NS4Z6

2) Get an eGPU and drive all three monitors from it. For instance:

https://www.amazon.com/Sonnet-Breakaway-Bundle-Sapphire-GPU-350W-TB3DEK/dp/B077K8KNDS

I'm highly confident #2 will work (and is still cheaper than getting all new monitors). #1 is a maybe, but much more likely to work than using an HDMI to DP or HDMI to DVI-D adapter. I'm not surprised that HDMI to VGA didn't work because the HDMI port in the Mini almost certainly doesn't have support for analog displays (it would need a RAMDAC).

Thanks for the suggestions. After a bit more research yesterday, I ordered the following active HDMI to DP converter:

https://www.amazon.com/Cable-Matter...sr=1-6&keywords=hdmi+to+displayport+converter

I will report back once I receive it and try it out. Fingers crossed.

The irony to all this is I could just buy a cheap new monitor with a HDMI input and use that as the third monitor (I confirmed that this will work with a TV), but I really want to use three matching monitors for my set up.
[doublepost=1543958000][/doublepost]

Thanks. This is the cable I used to connect the 2018 mini to my Asus monitor:

https://www.amazon.com/gp/product/B075V27G2R?ref_=pe_1811570_136791410_E_Asin_Title

I thought it would work, but no luck. I rechecked the port on the monitor by hooking up my 2012 mini with it's old mini display port to display port cable, and it works fine, so the monitor and the port are ok. Either it's the USB C to Display Port cable (which I'm returning), or it's something with the mini. I tried two of the USB C/Thunderbolt ports, didn't work with either. Rebooted with only the USB C to Display Port cable attached, and there was no signal to the monitor. When I reconnected the HDMI cable it worked fine.

This is the USB-C cable I used, and it works fine (although the DP release tab could be a little easier to use)

https://www.amazon.com/gp/product/B01J6DT070/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

 

[Moolani]

Well, the HDMI to DisplayPort converter arrived today; I hooked it up and it worked!

Three screen bliss on a Mac mini. I have wanted that for so long.

 

[F-Train]

Well, the HDMI to DisplayPort converter arrived today; I hooked it up and it worked!

Three screen bliss on a Mac mini. I have wanted that for so long.

Is this the Moshi?

 

[Moolani]

Is this the Moshi?

No. Cable Matters.

https://www.amazon.com/Cable-Matter...s=cable+matters+hdmi+to+displayport+converter

 

[enri1357]

Thanks for the suggestions. After a bit more research yesterday, I ordered the following active HDMI to DP converter:

https://www.amazon.com/Cable-Matter...sr=1-6&keywords=hdmi+to+displayport+converter

I will report back once I receive it and try it out. Fingers crossed.

The irony to all this is I could just buy a cheap new monitor with a HDMI input and use that as the third monitor (I confirmed that this will work with a TV), but I really want to use three matching monitors for my set up.
[doublepost=1543958000][/doublepost]


This is the USB-C cable I used, and it works fine (although the DP release tab could be a little easier to use)

https://www.amazon.com/gp/product/B01J6DT070/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

Are you able to use this Cable Matter usb-c-to-dp cable to see the Apple Bootup Logo from a cold boot? (shutdown 1min, monitor off, then startup and see the apple logo) I am having problem with cold boot no signal with FileVault enabled

 

[gusping]

Are you able to use this Cable Matter usb-c-to-dp cable to see the Apple Bootup Logo from a cold boot? (shutdown 1min, monitor off, then startup and see the apple logo) I am having problem with cold boot no signal with FileVault enabled

Me too on when using usb-c to DP (LG 4k monitor). It’s a pretty widespread issue. Very annoying. Hoping a software update can fix it.

 

[enri1357]

Me too on when using usb-c to DP (LG 4k monitor). It’s a pretty widespread issue. Very annoying. Hoping a software update can fix it.

yes, extremely annoying

 

[gusping]

yes, extremely annoying

I exchanged my original mini and this second one has the same issue. So i assume it’s software related. Luckily I rarely turn off my Macs.