976 Shuts Down in Tuner Mode

Just as the title says.... exactly 15 minutes after on, it shuts down. I power back up, back to tuner and good for another 15 minutes. Outlaw requests for a ticket don't pan out. Any ideas?

I know this may sound odd, but what else is connected to your 976 (via HDMI)? My appleTV would shut off my 976 through HDMI-CEC after some time when it was no longer the active source. Other displays and sources can behave the same way.

I haven't used the tuner in my 976 in the over three years I've owned it. But the specific input source shouldn't be any different from another. Is this the only source it will shut down with? Arbitrageur is right, but if that was the case, the HDMI control would affect the 976 when switched to any input.

I was thinking along the lines that it could be the TV shutting down everything after 15 minutes with no video signal detected (from the tuner input). Lots of dependencies in the theory that only the OP can fill in.