We installed a simple system about a year ago that consisted of a Denon AVR-689 - Cox STB - Sony DVD - Samsung LCD. The equipment was on the opposite side of the room , so we ran a 50' HDMI cable to the display ( same cable we use all of the time). Everything was fine until last we the customer called and was having video issues and had called the cable company. The cable guy came over and bypassed the Denon and connected straight to the STB and it worked fine.

We went by and did some troubleshooting and concluded that the HDMI on the Denon was not working so we ordered an AVR-791.Today we delivered and installed the new AVR and everything seemed to be working fine except when you change inputs you would see some white pixelation on screen and then it would disappear within a few seconds. After about 15-20 minutes we lost signal and not it seems that the new AVR is doing exactly the same as the old one.We bypassed it and the 50" HDMI straight to the tv works fine with cable and dvd. We also tested a new HDMI across the floor with no luck. It seems as if something is taking out the HDMI protion of the AVR's. All devices ( including the tv) were power cycled several times and we are using the same manufacturers 3' HDMI as interconnects. Any ideas or has anyone experienced similar issues?