Samsung 49KS8000 Says No Signal When X1 hdmi routed through Sony AVR.
Set up was working fine with Panasonic Viera Plasma that Samsung replaced. Signal is fine when HDMI from cable box is directly routed to TV. Have searched forums for a solution on this but have found similar problems, but no resolution of issue.
HDMI can be tricky. The combination of source, cables, receiver, and TV can cause handshake issues due to specs not exactly meeting HDMI standards.
Your new TV is 4k and the receiver may not like the HDMI 2.0 input. Try another input on the TV.
Try a different cable too.
Worse case there is no loss of quality if you run the cable box directly to the TV with HDMI and use the digital audio output of the box for audio to the receiver. Set the receiver to Dolby. If the cable box doesn't have digital out you can use an HDMI audio extraction device to provide one.