@mtomer...With any HDMI connected system, your connected devices fall onto three categories termed,
sink, sender and repeater.

The TV or monitor is the sink device, which receives the HDMI signal.
The AV receiver or processor, is an HDMI repeater device, which can send and receive HDMI signals.
Any input source device is an HDMI sender.

The HDMI sink, (TV or monitor) is the device that is most responsible for completing a successful HDCP handshake.

It is a far more complicated handshake procedure whenever any repeater device is in the mix. Some source devices originally did not support repeaters. Some of these needed a firmware update in order to accommodate them, and there still are some devices in the market that do not, like some of the cables boxes still in use.

The fact you are able to get the OSD and not the video, tells me that the issue is between the source device(s) and the 975.

Whenever a new HDMI connected device is added to any system, and you're having difficulty with handshaking, there is an established HDMI reset procedure to try.

Xenonman's procedure above (#99534) is pretty much the way to approach this. You should try disconnecting all HDMI cables at both ends and unplugging all devices from AC power. Then you can reconnect all the HDMI cables again , before reconnecting all the AC power cables.

With the new TV, are you using Hi-speed HDMI cables?