Hi, I'm Nathan.Sorry to hear that you're having trouble with this but I'll do my best to help you.
Are you connecting the main dvr (roamio) unit or the tivo mini box to this panasonic?
Yes that is correct, you want to use the breakout cable, and it needs to be plugged into the AV (not component) port.
You also need to have then the red/white/yellow on the tv, and the tv needs to be set (using the tv/video or input button) set to the av/video input mode.
Which ports did you use? If you use video 1 ports for example, the red/white/yellow rca cables, then you set the input mode to video1
Can you, temporarily, hook the roamio up to another (newer) tv, go into the settings menu, then set the output format on the tivo to 480p,
then back to the panasonic on the av breakout
No problem, take your time.
If no change, I'd like to have you try testing another device on the tv as well, like a dvd player or vcr, so we can make sure the av ports on the tv are even functional in the first place.
HI Dave, sorry I missed you earlier.
You could hook the dvd to another tv to make sure it is working, but if the tivo works elsewhere too, and neither are working on the panasonic, that indicates a hardware fault in the panasonic.
Not at all surprising to see base on age, that tv is well over doulbe its service life at this point.
Do you have anything with a coax output on it (like an old cable box, vcr, etc)? If so, can you try that and see if you can get any signal through the panasonic on channel 3 or 4?
Do you need more help with this, Dave?