imac 27 inch 2013 connect to mac pro target display, black screen

Question

imac 27 inch 2013 connect to mac pro target display, black screen

Im trying to connect my brand new 2013 MacPro (3.5 GHz 6 core)to my imac 27 inch 2013 (os x yosemite version 10.10.5) using a thunderbolt cable - but when i press command -F2, it just goes to a black screen. after a while the MacPro asked is I want to set up the new mac but then my esc key and command F5 keys dont work so i just sit on a black screen.. Then when I get out of Target Display it comes back to my normal screen with the brightness at 1 bar.

Any suggestions? iv been trying to figure this out for 2 days now.

Posted on Oct 4, 2016 12:45 AM

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Answer 1

lllaass

Level 10

210,519 points

Oct 4, 2016 1:39 AM in response to jarred stedman

Have you tried:

If Command-F2 doesn't work

If your iMac doesn't switch to Target Display Mode when you press Command-F2, check these things:

Make sure the iMac you're trying to use as a display supports Target Display Mode.
Make sure you're pressing Command-F2 on the keyboard that's connected to the iMac you want to use as a display.
In Keyboard System Preferences, if the checkbox is enabled for Use all F1, F2, etc. keys as standard functions keys, the key combination changes to Command-Fn-F2.
Make sure your Mini DisplayPort or Thunderbolt cable is connected to both computers.
If you're currently logged in on the iMac you want to use as a display, try logging out to return to the login window. Then press Command-F2 again.
Some older Apple keyboards and third-party keyboards might not allow Command-F2 to toggle display modes. If this happens, use the keyboard that came with your iMac to toggle Target Display Mode on and off.
If your iMac is currently started up in Windows, it won't enter Target Display Mode. Target Display Mode isn't supported in Boot Camp.

You are using a Thunderbolt cable, right?

A mini displayport cable will plug into a Thunderbolt port since they look the same. Does your cable plug have a lighting bolt icon n the plug ends?

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Answer 2

Oct 4, 2016 2:50 AM in response to lllaass

Hi Illaass

thanks for writing.. I have read the info page a few times now so I have checked off and double checked off all of those options above a few times.

And yelp, i bough a new thunderbolt cable from the mac store today - but still no good.

The Imac is kicking into Target Display Mode, but then the MacPro isn't sending the signal to the display or something.. And each time I turn on TDM, the MacPro starts talking about how to enable voiceover mode.

Any other ideas ?

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Answer 3

lllaass

Level 10

210,519 points

Oct 4, 2016 6:48 AM in response to jarred stedman

For the Mac Pro:

- Try resetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

https://support.apple.com/en-us/HT201295

About NVRAM and PRAM

For the iMac only reset the SMC

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