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LawrenceHare Level 1 Level 1 (5 points)

I am running a new 27" iMac and a MBP 17", both running 10.7.4. Both have Thunderbolt ports. I bought a thunderbolt cable and wish to use the iMac as an external screen for the MBP - Target Display Mode. I have connected both togther via the thunderbolt cable and used Cmd-F2, but nothing. System Information identifies the Thunderbolt ports (2 on the iMac) and nots No Devices Connected.

 

Cannot make it work.

 

Any ideas?

 

Thanks - Lawrence

  • BDAqua Level 10 Level 10 (119,720 points)

    No idea, but I wonder if the TB cable is the same as a Display port to TB cable?

  • LawrenceHare Level 1 Level 1 (5 points)

    Not sure I understand! I thought the display port was a subset of the TB port, so I could use a mini display cable between TB ports or between a TB and display port for display, but it would not get TB performance.

  • BDAqua Level 10 Level 10 (119,720 points)

    I'm not sure either, I know it's compatible at least one way, just can't find out for sure the other way.

  • captfred Level 7 Level 7 (26,265 points)

    To do Target Display mode between two Thunderbolt equipped machines, you must use a Thunderbolt cable.

  • LawrenceHare Level 1 Level 1 (5 points)

    That is what I thought. I bought a TB cable from the Apple store last weekend, I have a brand new 27" iMac and a MBP I bought late last year - both equipped with TB ports. As best as I can see, I have done everything right. I have transferred files using target disc mode, fast as blazes, not I want target display mode - but I cannot get it to work!

  • captfred Level 7 Level 7 (26,265 points)

    Just to recap the procedure..  You hook them together and on the iMac 27" keyboard you hold down Command and click F2

  • LawrenceHare Level 1 Level 1 (5 points)

    Well, I did not CLICK F2, I pressed it. Um - am I missing something?

  • captfred Level 7 Level 7 (26,265 points)

    Try  FN CMD F2     This can be reversed in the Keyboard Preference pane > Use All F1, F2, etc keys as standard function keys.

  • LawrenceHare Level 1 Level 1 (5 points)

    Bingo! Thank you... The problem was that I use a Matias Tactile Pro keyboard, I do not get on with the Apple keyboards, I like a full-throw key and the Alps keyswitches provide a good solid feed-back - I am twice as fast on the Matias as on the Apple keyboard.

     

    The reversal of the function keys and the use of the 'fn' key I know about as I have it on my MBP, so I tried reversing the F-key action in the system preferences as you suggest, but using the Matias the Cmd-F would not work either way. When you suggested the FN key I grabbed the little wireless keyboard that came with the iMac and tried FN CMD F2 and it worked.

     

    Once in five times it does not, the screen goes dark, puts a few squiggles up in the top left and sticks the cursor on the squiggles, and nothing will do anything more - until you hit FN CMD F2 again when it reverts to iMac mode. Another crack and it works fine.

     

    Another issue I hit is that the TB cable can be inserted either way around on the back of the iMac! As it is hard to see behind the thing when inserting the cable, I got the plug the wrong way around, but it inserted just fine! Nothing worked of course. I discovered this when setting up taget disc mode, which I have used before, even with this cable, and which did work. So when it did not I started looking at the cables and noted that the little curves on the socket in the back of the iMac were on the opposite side from the TB plug (it is hard to see the polarity at the back of the iMac, it is big and close to a wall and it is hard to get a good look at the sockets). I rotated the plug 180 degrees and it went back in with the same amount of pressure as before and now target disc mode DID work. I cannot insert it incorrectly on the MBP, only on the iMac. I called AppleCare and the guy said they knew of this problem.

     

    Thanks again.

     

    Lawrence

  • captfred Level 7 Level 7 (26,265 points)

    Thanks for the feedback Lawrence.  I'll remember this for future TB target display mode problems. 

  • Kenneth Cohen1 Level 1 Level 1 (65 points)

    My problem is along the same lines. I have a new Mac Mini with a Thunderbolt port, and a 2010 27 inch iMac with a Mini Display Port. I have connected them with a Thunderbolt to Thunderbolt cable, but target display mode does not work, command-F2 just produces beeps. (I started up the Mini first, then the iMac. I'm using a wired 2007 aluminum Apple keyboard connected to the iMac.

     

    At a nearby Apple store, I was told that I need to use a Mini Display Port to Mini Display Port cable for this, that a Thunderbolt cable will not work - but Apple no longer sells a Mini Display Port to Mini Display Port cable (nor can I find one anywhere else), so how am I supposed to do this?

     

    Any help will be most appreciated, I'm pretty frustrated. Thanks.

  • LawrenceHare Level 1 Level 1 (5 points)

    In my case it was the keyboard, there is something spooky about the Command-F2 that works only on a Mac keyboard, when I tried the little aluminum keyboard that came with my iMac - bingo, it worked like a charm!

     

    I use the Matias Tactile Pro keyboard on all my Macs, I really have a hard time with the aluminum ones, the keys and my fingers just do not get along, the Tactil pro have a full travel switched key and I find them vastly superior to the aluminum keyboard - they are like the keyboards that Apple USED to make - I still have one of their old keyboards - excellent. The Tactile Pro I have does not behave like the Apple keyboards so the Command-F2 does not work. That said however Matias is coming out with a new version of the Tactile Pro that DOES behave like the Apple keyboard and the Command-F2 DOES work. Needless to say I shall be getting one...

     

    Do make sure that you are using the Apple Version of the F2 key and not the "Standard F-Key" version! You may need to press the "Fn" key along with the Command-F2 or set the keyboard settings in the System Preferences for the keyboard.

     

    Cheers - Lawrence

  • Scottiemac11 Level 1 Level 1 (0 points)

    Hey Lawrence,

     

    I've read over this post and I am still not having any luck!

     

    MBP 15" 2012 > iMac 27" 2012 (both with thunderbolt) using a thunderbolt cable and pressing command+F2 won't work.

     

    I don't have a standard keyboard but I pulled up the on-screen keyboard but it still doesn't work!!

     

    Any ideas?

     

    Thanks in advance,

    Scott

  • LawrenceHare Level 1 Level 1 (5 points)

    The keyboard that came with the 27" iMac should work - did you not get one? Mine came with the small bluetooth aluminum keyboard. I checked out the cable using target disc mode to make sure the cable worked - this is how I discovered that I could insert it into the back of the iMac inverted! I could only insert it one way into the MBP - the proper way, but on the iMac it would go in either way up - and only work when inserted correctly of course.

     

    I connected the MBP and the iMac using the thunderbolt cable and started the MBP with the T key pressed so it came up in target disc mode. Then using the iMac I verified that I could see the MBP and transfer files - and, incidentally, that the transfer was blindingly fast. Then I fired up the MBP in normal mode and using the keyboard that came with my iMac I pressed Command-F2 and then fn-Command-F2 - because I had the function keys set to normal function key mode - I think. Either way, one of these keypresses worked fine.

     

    In speaking with Matias who makes the keyboard I use I learnt that the Command-F2 combination is unique in some way to the Apple keyboard and the iMac connected to it, other keyboards do not send the same signals. Matias is coming out with version 4 of the Tactile Pro that WILL send the same signal as the Apple keyboard but the version 3 I am using does not work - ONLY the Apple keyboard works. I suspect that the on-screen keyboard will also not work in the same way. Can you borrow a bluetooth keyboard from someone or from the Apple store?

     

    Lawrence

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