Detects Display But Blank

[Carlo]

Originally Posted by darnelld

Hi Christian,

Thanks for the reply. I am using an apple 24" HD cinema display (displayport not thunderbolt). I connect the monitor to the display port on the Mac and it works fine. When I then unplug it and use the USB diamond card the display is blank. I use a dvi -2- mini displayport cable to connect through a KVM switch (which also works if I go through the computer port) then to the display.

The only variable left is the diamond device.

Well that's a DisplayPort only display. The USB adapter you are using is DVI, and with a simple DVI to miniDP cable you cannot create a DP signal from a DVI one. Those cables are used if you have a DisplayPort Mac and you want to drive a DVI display: most DisplayPort outputs (not inputs!) also include DVI and VGA signals.
You are in the same situation as anyone with a pre-DP MacBook Pro trying to connect to the 24" Cinema Display: you would need a DVI to DP adapter that's going to cost more than your USB to DVI adapter.

That is the only solution I can see at the moment.
Needless to say, the other issues described in this thread look to be very different.