My TIVO box and TV are connected with an HDMI cable and were working fine for many months, until one morning I switched on the TV and there was no picture or sound. I pressed a few buttons and all of the TIVO menus appeared, I could then hear the TV channels but there was still no TV picture.
An engineer came out and he swapped over the TIVO box but this didn't change anything, other than losing all of my recordings.
I have turned everything off and on again - no change.
I plugged the TIVO box into another TV and everything was fine. So I thought my main TV might be the problem. To test this I have plugged another HDMI device into my main TV and it works fine. So it seems that the TIVO box is fine and the TV is fine, they just don't like each other.
Fantastic. Thank you so much for answering this for me. Samsung (the make of my TV) had basically told me to go away when I got in touch with them, I will go back into battle with some more information on my side.