Flicker on Decklink duo 2

Hello,

i have a decklink duo 2 on a ASRock Z87 Extreme4 Board with a i7-4790.
The DD2 Card is in the PCI-E 4Slots and the Bios says it runs with 16Lanes.

Windows 10 recognizes the card.

For a test I use a canon Camera with HDMI-Out and a HDMI-SDI Converter.

The Issue:
The pictures on the PC is black but every 2 Seconds the pictures of the camera flashes for a half second.

Where is the Problem?

Hello,
I have a similar issue with the DUO 2 connected to a Gigabyte B85M-D3H.

As I get a stable signal with a capture card of another Brand it can't be related to cables or the Converter, doesn't it?

Either port of the Duo 2 brings me a signal of the camera but it flickers every now and then.

Help is greatly appreciated.

Marc