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skel_73

macrumors member
Original poster
Feb 12, 2002
38
18
Toronto
I just got my new MacBook Pro with Touchbar. Maxed out, souped-up. It is replacing my 2012 Retina MacBook Pro.

My old set up was to connect 2 Dell monitors (a Dell U2715H and a slightly older one) to the MacBook using 1 connection through an OWC Thunderbolt hub (display port connection) and the other straight into the MacBook Thunderbolt port with a Displayport cable. No issues, worked flawlessly.

With this new machine, I bought 2 Thunderbolt 3 (USB-C) to Thunderbolt 2 adapters, so that I could connect the monitors.

Nothing is working well.

With the Dell U2715H, the computer will expand the desktop as if the monitor is there, but the monitor will not sense a signal and will remain black. If I turn everything on and off 5 or 6 times, eventually it will show the image.

With the other monitor, it will work only if I connect it through the OWC hub. So the adapters were expensive and were bough solely to support my ability to use the 2 monitors, and they are not working.

Apple's Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter will NOT support a Displayport connection to a monitor, unless (weirdly) it is run through a hub like the OWN Thunderbolt 2 hub. And even then, you may have to turn everything on and off multiple time to get the screen to show.

This laptop cost a lot of money and I need it for productivity. External monitor support via Displayport should be something that works rock solid out of the box.

Anyone else out there figured out a fix for this?
 

xraydoc

Contributor
Oct 9, 2005
10,835
5,305
192.168.1.1
You made the mistake of trying to use Apple's TB3 to TB2 adapter for monitors. It specifies it doesn't support DisplayPort video. There are USB-C to DisplayPort video cables, however.
 

Pencilnink

macrumors member
Oct 5, 2016
48
17
I just got my new MacBook Pro with Touchbar. Maxed out, souped-up. It is replacing my 2012 Retina MacBook Pro.

My old set up was to connect 2 Dell monitors (a Dell U2715H and a slightly older one) to the MacBook using 1 connection through an OWC Thunderbolt hub (display port connection) and the other straight into the MacBook Thunderbolt port with a Displayport cable. No issues, worked flawlessly.

With this new machine, I bought 2 Thunderbolt 3 (USB-C) to Thunderbolt 2 adapters, so that I could connect the monitors.

Nothing is working well.

With the Dell U2715H, the computer will expand the desktop as if the monitor is there, but the monitor will not sense a signal and will remain black. If I turn everything on and off 5 or 6 times, eventually it will show the image.

With the other monitor, it will work only if I connect it through the OWC hub. So the adapters were expensive and were bough solely to support my ability to use the 2 monitors, and they are not working.

Apple's Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter will NOT support a Displayport connection to a monitor, unless (weirdly) it is run through a hub like the OWN Thunderbolt 2 hub. And even then, you may have to turn everything on and off multiple time to get the screen to show.

This laptop cost a lot of money and I need it for productivity. External monitor support via Displayport should be something that works rock solid out of the box.

Anyone else out there figured out a fix for this?

I made the same mistake and bought the Thunderbolt 3 to Thunderbolt 2 adapter assuming it would work with DisplayPort.

Unfortunately that doesn't work so I bought a USB-c to display port adapter on Amazon from Cable Matters and it works perfect.

Your DELL U2715H has DisplayPort Out, why not daisy chain both externals and save your thunderbolt 3 ports for other accessories?
 

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skel_73

macrumors member
Original poster
Feb 12, 2002
38
18
Toronto
I made the same mistake and bought the Thunderbolt 3 to Thunderbolt 2 adapter assuming it would work with DisplayPort.

Unfortunately that doesn't work so I bought a USB-c to display port adapter on Amazon from Cable Matters and it works perfect.

Your DELL U2715H has DisplayPort Out, why not daisy chain both externals and save your thunderbolt 3 ports for other accessories?


I tried daisy-chaining and for some reason could not get it to work. That would have been the perfect solution. The other monitor is the Dell U2711.
[doublepost=1479735031][/doublepost]Thanks for all the replies, much appreciated.
 

Pencilnink

macrumors member
Oct 5, 2016
48
17
I tried daisy-chaining and for some reason could not get it to work. That would have been the perfect solution. The other monitor is the Dell U2711.
[doublepost=1479735031][/doublepost]Thanks for all the replies, much appreciated.

Ah i think it didn't work because the Dell U2711 doesn't support DisplayPort 1.2.
 

up324

macrumors newbie
Jan 5, 2018
1
0
Nope, the MBP with MacOS specifically doesn't support Displayport MST Daisy-chaining. All the hardware does (Windows bootcamp on the MBP can do it), but Mac OS doesn't.
 
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