scuwp: Micro-loss of signal is a known TiVo issue and I am sure there have been other threads on this. There are display output settings in the TiVo (somewhere under settings>video>display or similar off the top of my head) You need to ensure that the TiVo video output matches what the TV can handle (or the amp pass-through) from memory most on-line comments suggest that one of the "hybrid" settings works best. There is about 6 to choose from and try out.
Thanks for the suggestion, I have tried both fixed and Hybrid settings with the same result.
The fixed 1080i setting it was on when it started doing this is the same one it has been on for over a year prior without any signal loss. I definitely seems to be something that has developed.
Another forum suggested that it might be a HDCP handshake issue and I have taken the steps suggested in that thread to no avail. Something is definitely bugging the HDMI signal causing it to reconnect.
Could another device in my setup be intermittantly spiking the TV's media box causing the TV to re-establish the connection? I can't recall whether this started before or after I got my Blu Ray player at the end of last year. I will disconnect that from the TV for a few days and see if that has any effect.
The TiVo has no interupted signal as I can skip back and play the few seconds I missed during the black out.
Alternatively I could buy a replacement at $360 from TCom and move this one to the bedroom and use the wireless adapter finally.