3 Replies Latest reply: Jul 5, 2014 4:57 AM by jathu116
tymccarty Level 1 (0 points)

I have a little bit older 20" iMac (purchased around 5 years ago), model number A1174.  Processor is 2 GHz Intel Core Duo with 2 GB 667 MHz DDR2 SDRAM.  Using Mac OS X Snow Leopard (version 10.6.8).


Our church purchased the TripleHead2Go Digital Edition to run with ProPresenter.  We installed the Matrox PowerDesk software and when it said to plug the TripleHead2Go into the USB port it immediately shut off the computer.  After disconnecting and reconnecting the iMac's power supply, we were able to reboot the computer with the TripleHead2Go already plugged into the USB connection.


From the iMac we are using a Mini DVI to VGA adapter to connect to the VGA port of the TripleHead2Go and then DVI to VGA adapters to connect to our displays.  We can get screen 1 to show up out of the TripleHead2Go, but nothing from screen 2 and 3.  Running the Quick Setup from the PowerDesk software states that "one or more monitors (or displays) aren't connected.  Hitting the Detect button does not help and there is a check box for "Only use two displays (1 and 3).


Connecting the TripleHead2Go to my PC works fine.


Is it possible that my USB port doesn't have the power needed to make the TripleHead2Go function properly or is there something else on the iMac that needs to be done?  I am normally a PC guy, but handle Macs on occasion too.  I found that Matrox has a USB Power Adapter Kit for $40 and wondered if that might do the trick.


Thanks for any help!



iMac, Mac OS X (10.6.8)
  • tymccarty Level 1 (0 points)

    Problem solved.  Part of the problem was a bad DVI to VGA adapter on one of the outputs of the TH2Go.  Other problem was not setting the correct resolution for the TH2Go (2400 X 600) and needing to think of it as one monitor split into 3 sections instead of thinking of it as 3 separate monitors.  Also had to get used to how the iMac handles setting up resolutions on separate displays (resolution window appearing on each display).  The message I was getting from the PowerDesk software, "One or more monitors (or displays) aren't connected", also added to the confusion.

  • walterwatzlav Level 1 (0 points)

    hi there, i'm struggeling with the same issue (apart from that i am on a macbook pro). if you have a spare sec and if you don't mind could you give me some more details? i understand i have to devide the global resolution settings into the 2/3 monitors which i am using? any advice is much appreciated!

  • jathu116 Level 1 (0 points)

    I have a similar issue here. I biught triplehead2go Digital edition and bought tmacbook pro vga adpater. Only 1 screen is showing up, screen 2 and three is not showing up as flickering pitch black screen. I can see some areas of the display but pitch black could this be resolution problem or vga adapter problem. What could be the issue here???