Just received a replacement ("new") Cisco ISB 7500 DVR. After installing, I have sound but no picture. I can change from channel to channel, and can view the menu, but other than the on-screen choices of the menu, no picture. Installation simple, using ony HDMI to connect to TV. Worked fine (i.e., had picture and sound) until 2 days ago when the prior Cisco froze.
cooblake - The HDMI interface is not just a physical connection. It communicates data from the TV to the STB. The TV tells the STB - I am not a recording device. If the STB does not get this message it may prevent the picture. Since this communication is accomplished by different groups applying the HDMI standard, it is an opportunity for a mismatch.
I believe another symptom is that the U-verse menus and promo channels display a picture.
To determine if this is what is causing your problem remove the HDMI connector from the STB side & use component cables.
You may be able to prevent it by turning on the TV first. To try that, first reboot the STB to clear any possibility of it applying an existing HDMI memory.
*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.