I have a Panasonic Viera LCD TV and a Virgin Media tivo box. When I turn the TV on in the morning, the colours are inverted, like a film negative. This happened once ages ago, but now its happening every morning. Replacing the HDMI cable makes no difference. Cycling power to the TV fixes it, but so does cycling power to the tivo, so I'm not sure which device is faulty?

Do you leave the TiVo box on or in standby when not in use? If you leave it in standby which do you turn on first, box or TV?

I'm just wondering if there is a HDMI handshaking issue? If you leave the box on all the time and just switch the TV off the handshaking might screw up. Switching either device off and back on might just kick it into working OK. So you could experiment with putting the TiVo into standby then try switching the TV on first then the TiVo and if that has no effect try switching the TiVo on first then the TV.

If neither has any effect then you can only really work out which is at fault by substitution.

First simple test is to use a different HDMI port on the TV if it has one free. The try some other device on the same HDMI port as the TiVo if you have anything like a DVD/Blu-Ray player.

Less easy to achieve perhaps is trying a different TV with the TiVo box. But not really any easy way to work out which device is playing silly games. The real bummer is where both devices work perfectly OK when connected to something else but simply don't like playing nicely with each other!

If the problem is still present after you have eliminated all cables and connections, a search suggests it could be something more serious, it could be either the Video or Tcon board.

How to tell which board is faulty - If you get the same effect on the menu screen it's the Tcon board, if the menu is normal it's the Video board.

I'd look to eliminate the Tivo box as the culprit by starting the TV using its own tuner if possible - if it still happens then, you're looking at a problem with the set itself. And as Deacon1972 has said, the T-con board has been identified as the culprit when other posters have reported similar symptoms.

Which set is it and how old? Generally Panasonic's are very reliable.

That sounds like the easiest thing to try, next time it happens I'll switch over to the internal freeview tuner.

It's 6 years old, not sure what the model number is without digging out the manual, but it's a 32 inch.

Based on your description it sounds as if the problem is to do with the HDMI handshake and how the Tivo and the TV talk to each other about the colour format that should be used. If you have a Blu-ray player you'll see an option in the set-up menus to change the HDMI colour format from RGB to YCbCr or Auto. The first tow formats are fixed, and they force a BD player to output one colour format regardless of the encoding on the disc. Auto simply reads the colour encoding format on a disc and follows suit. However the output of the source device is set a TV should be able to 'read' the signal and recognise which is the correct processing mode to apply.

I'm not sure if a Tivo has the same sort of output options, but it would be worthwhile switching off any HDMI communication on the TV (Viera Link) and then making sure the firmware is up-to-date on both the TV and the Tivo. BTW, Tivo doesn't have CEC AFAIK.

OK, this morning I turned the TV on from standby (the tivo box had been on all night) and the colours were inverted again, so I tried a few of your suggestions. The TV's own on screen menu was fine, the blu ray player on HDMI1 was fine, and when I switched back to the tivo box on HDMI2 it was fine too, so I'm guessing changing inputs then changing back again forced a new handshake?

Yep, it did