What board controls the input, my input comes up HDMi and the screen stays black as the HDMI disappears.

The problem is the main board, you may look at the stick on the main board to find the part number (usually as BN96-XXXX), you may find a used one from EBay.

Try connecting directly instaed of through the switch box.

Check power supply capacitors.

Hi Rory,
I hope you have chosen the correct input source ie. RF, AV1, AV2, PC or HDMI to which you have connected the cable. Despite choosing the correct input source if the TV says no signal means it is not reading the signal. In that case the main board is defective. A good technician who knows component level repairing can repair the main board. Otherwise you will have to replace it.

TRY connecting thru your composite connections to see if that works, also try a new HDMI cable. if it works thru composite & not the HDMI input then you have either a source issue or a bad MAIN/IO PCB

for some reason it is not seeing you cable signal. you will need to make sure you have it set up for cable and not air. check your input options, like tv/av/hdmi/ ect hope this helps

Buy another HDMI cable.Try another HDMI cable with another HDMI hub on the tv port.If u still have the same problems,mean the whole main tv Tuner signal board have problems and the caused.Tries websites like Shopjimmy.com,Ebay.com to buy a whole new refurbish tv Tuner signal board for the replacement.

Do you get a picture at all? Its just not HD? The TVs ability to show HD depends on the source, it will not convert an SD picture into HD without the proper source. If you have no signal, make sure your using the correct input on the TV.

Easy, You plug either the HDMI cable into one of the HDMI inputs and then plug it into the XBOX 360. If you are using either the component or composite cables then plug them into the proper color coded input.

its the cable itself comming into the house.