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actionpics Level 1 (5 points)

I have a 27" Thunderbolt Apple monitor hooked up to a MBP. I would like to hook up a Dell monitor that has a DVI-D input. I would like to hook up this second monitor using a mini display port to DVI-D converter coming from the Apple 27" Thunderbolt port. Will this work? I have it hooked up that way at the moment, but the Dell monitor isn't being recognized (it is just black).

27" Thunderbolt display, Mac OS X (10.7.4)
  • X423424X Level 6 (14,215 points)

    You can only attach a TB device to a TB source.  No adapters are available.


    Confusing Mini DisplayPort with Thunderbolt


    Thus you cannot connect that TB monitor up to your Dell.


    Note to keep the terminology correct, your Dell has a DVI video output, not input.

  • actionpics Level 1 (5 points)

    I forgot to add that I can hook the Dell monitor directly to the MBP through the Thunderport and it works fine. So that rules out the cable and adapter.

  • actionpics Level 1 (5 points)

    Hum...I asked this specific question to a tech guy from an Apple Store and also a Geek from Bestbuy. They both said that it wouldn't be a problem. Is the Thunderport in the MBP different than that from the monitor? The Dell works fine by itself going through the laptop.

  • X423424X Level 6 (14,215 points)

    Read the article I linked to.  You can connect a displayport device to a TB source.  Your MBP is the TB/mini-displayport source so that is why you displayport monitor works.  That is opposite of what I stated above.  This stuff is not bi-directional.

  • actionpics Level 1 (5 points)

    I read somewhere that someone had hooked up a Thunderbolt hard drive to the monitor port and then was able to do a DVI-D second monitor connection. Why would that work?

  • X423424X Level 6 (14,215 points)

    Whether it works or not you are still viewing this in the wrong direction.  These are all a TB computer output to some other device (TB or mini-displayport or possibly to an appropriate mini-displayport adapter).  The root of the chain is always the TB-equipt computer.  You asked basically whether a non-TB-equipt computer, i.e., your Dell, could output to a TB device.  The answer is sill no.


    TB devices can be chained.  And even those have some restorictions and limitations.


    Thunderbolt ports and displays: Frequently asked questions (FAQ)

    Displays: Mini DisplayPort display must be last in a Thunderbolt chain


    What you may of heard was you could daisy chain a TB external drive to a TB display which is connected to a TB computer.  I think there are may be problems connecting a display to the TB external drive DVI or otherwise).  But even here the direction is from a TB computer output to the chain to the devices.


    If I cannot convience you by now about this then hook it up to your Dell for yourself and view the black screen.  Nothing is going to be damaged.

  • actionpics Level 1 (5 points)

    Forgive me as I'm new to Macs (about 1 week) after a lifetime in PC land. You posted a link that says Mini DisplayPort display must be last in a Thunderbolt chain. That is exactly what I'm trying to do. Macbook Pro (with Thunderbolt port) to 27" Thunderbolt display to DVI-D monitor using a mini display port to DVI-D adaptor. I understand this doesn't work, but now I'm trying to figure out why. I've found some other post on here asking the same question so at least I'm not the only one who is confused-:)

  • X423424X Level 6 (14,215 points)

    You originally said you wanted to hook a apple 27" TB display to a Dell and I said that can't be done.


    As for the daisy chaining, MBP-->TB display-->DVI display there are some limitations of chaining displays to MBP as a function of model.  That FAQ link I gave earlier has a table showing the limitations.


    Also, you never said what the resolution of that DVI monitor was.  If it is greater than 1920 x 1200 then you need a dual link DVI adapter rather than a simple single link adapter. 


    If the DVI monitor is less than 1920 x 1200 then I don't know why it wouldn't work except for possible limitations of TB itself.  Maybe only a mini-displayport monitor can be chained to a TB display (if so that applies to any sized DVI monitor -- single or dual linked).


    Note, if it is a single link DVI then if you want to add a second monitor you might consider the following:


    Newer Technology USB to DVI / HDMI / VGA HD Video Display Adapter


    In other words connect it via USB.  I have no idea what the video perfomance is pumping a video signal through a usb2 port.

  • actionpics Level 1 (5 points)

    Thanks for all of the replies! The Dell monitor (U2410) would run at 1920x1200. I was under the assumption that the Thunderbolt port in the 27" Thunderbolt display was the same as the Macbook, but that is turning out not to be the case. The last part of what you mentioned is exactly what I started looking into this morning. Performance wise all I'm really looking for is to put Photoshop toolbars on one screen (non-thunderbolt one) and then just the image I'm working on on the other. If nothing else, I'm learning a lot!

  • actionpics Level 1 (5 points)

    Small update. Ironicially I just happen to have a Seagate hard drive that has a Thunderbolt upgrade ability. I was starting to think if this setup would work (running the monitor to the Thunderbolt harddrive and using a display port to DVI connector to a second monitor) then I came across this article: -on-your-macbook-pro/#respond. This looks it might work. Anyone have experience with this type of setup?

  • X423424X Level 6 (14,215 points)

    Why do I think the guy is just lucky?  And based on the number of posts here with problems with goflex externals (their software at least) he may end up regretting paying for what may amount to being a $189 video adapter.  But it's interesting it works at all.  Wonder if the USB is also passed through.

  • actionpics Level 1 (5 points)

    There is a YouTube video I think I saw where someone else did the same confirmation, but with one of the LaCie Thunderbolt drives instead of the goflex. I think there is something different in the Thunderbolt port in the Thunderbolt display. EIther that or there is a weird software glich.


    Is there any developers have the Mountain Lion OS installed that can test the original idea of using the Thunderbolt display's port to a DVI montior connection and see if it works?

  • X423424X Level 6 (14,215 points)

    Well if there are, since ML is still not publically released, and under NDA, no one can say here one way or another.

  • actionpics Level 1 (5 points)

    Figured I'd do a little update. I already had a goflex 2TB drive that was Thunderbolt upgradeable. I was on sale at Bestbuy so I had picked one up, plus I had liked the idea of it being Thunderbolt ready. As you know from my original post I've been trying to get a DVI-D monitor hooked up as a second monitor. Going from the 27" Thunderbolt display using an adaptor to this second monitor didn't work. After reading the article that I posted above I figured what the heck I'll get the Thunderbolt adaptor for my goflex. If nothing else I just got a wicked fast external harddrive. I hooked the up the adaptor for the goflex with a Thunderbolt cable to the 27" monitor Thunderbolt port and then hooked my adaptor and DVI cable to the other montior and it fired up right away! I'm very happy now. I've got the two monitors I wanted and a Thunderbolt external drive. I know this isn't probably the cheapest (could have gone with USB to DVI adaptor route, but I'm happy.


    What this all comes down to is there is something different (software or hardware wise) with the 27" Thunderbolt display's Thunderbolt port. Would be nice if this was fixed in Mountain Lion, but in the meantime I can confirm the setup used in the article above works perfectly!

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