I've had my Samsung LE46C750 TV for about 10 months now and I've recently started having an issue where it can't find the signal from any HDMI cable. I've got a PS3 connected to HDMI 1 and an Xbox 360 in HDMI 2. Periodically, I will switch the TV on only to find that it can't find the signal from either console. For example, if it's on HDMI 1 with the PS3 switched off, the screen just displays the message 'Check signal cable'. When I switch the PS3 on, instead of getting the PS3's display, the message just changes to 'No signal - Check connected device's power, cable connection, and source selection' - as if it's detecting that something's there, but isn't getting any data from it. Likewise, if I press 'Source' on the remote and look at the list of channels, HDMI 1 will be in the bottom, greyed out section when the PS3 is off. Switch the PS3 on and it moves to the top, white section, so it's obviously detecting that the PS3 is there, but there's no display. And exactly the same happens with the Xbox 360. There's also a Wii connected to the component input, and a PS2 in Scart 1, but they work absolutely fine at all times and seem to have no bearing on this issue at all. The only way I've found to fix it is to unplug both HDMI cables, power off the TV at the mains for 30 seconds or so, then reconnect the cables (or at least just the one for the console I want to use at the time) and power on. Then everything works normally for a while, but the problem recurs at least once a day. This started happening about 4-6 weeks. My TV previously had a completely different problem, where any analogue signal (from the tuner, scart or AV sockets) was not displayed correctly - it was constantly waving/wobbly. This seemed to be a loose connection, as wiggling a scart cable or tapping the back of the TV would fix it temporarily. I recently got fed up with that (mainly due to wanting to play some PS2 games) and replaced the main board. After replacing the board, I checked for firmware updates and found that 3014 was out, so I installed that. So I'm not sure whether it was caused by the new main board or the new firmware. There has since been another firmware update, 3015, which I've installed, but it hasn't fixed the problem. The new main board is otherwise working fine, so I'm going to attempt to downgrade the firmware and see if that helps. Does anyone know what could be causing this? Is this a handshake issue? What could I do to work out the cause and attempt to fix it?