TV doesn't automatically show signal from Windows Media Center

"This problem seems to affect many people (as per search engines) with the most suspected/mentioned cause being insufficient drivers from ATI (NVIDIA apparently has updated its drivers for related issues successfully, while ATI tried that too, but some users still seem to have the same issue afterwards).

Consequently you might try to find updated drivers for your video card, but you should probably try the following workaround first to confirm the direction: several users are having success with a little program called hdmiOn. You could try this too by assigning a Windows shortcut key to run hdmiOn.exe whenever you lose the signal.

For more details and/or different solutions you may find e.g. this thread helpful (rather lengthy though), which is addressing a similar issue and resolution experiments.

Update:

With hdmiOn fortunately providing a workaround now, theDude19 seems to be spot on regarding the actual cause being loss of Extended display identification data (EDID), as hdmiOn.exe is exactly enforcing a resend of EDID by simply turning the monitor off and on again.

Given the simplicity of this fix one would indeed think this to be the responsibility of the video driver, however, as usual, the handshake between the involved hard- and software entities might be insufficient on all sides..."

"I think you need to diagnose the problem a little more. You need to find out if media center is blanking the screen or if windows power saving is, or if it's showing the screen but the TV isn't picking up that input right away.

I'd double check the output with a display on another port, and check the sleep settings in windows power saving and media center.

I can add that I've never quite had media center sleeping and coming back with the ""power"" button.. I generally just let it timeout and it wakes up with the green button."

"I believe it's a problem with HDMI - as far as I know, the computer doesn't output an HDMI signal, but a DVI one (which is subset of HDMI) when the TV tries to hand-shake, there's nothing there (handshaking isn't required for DVI).

Does your TV have a DVI port? If so have you tried using that?"

"Not a solution but a possible work around -

After you have turned the tv and back on, is it possible to unplug the HDMI cable from the tv and plug it back in?

Hopefully it will re-do the handshake :S

Again, just a idea off the top of my head as a workaround, hopefully it will work."

"I have the same problem. This post seems to offer the solution:

No Signal After Turning TV Off and Back On

I will try it over the weekend, but it echoes the issue raised by th3dude and provides a solution."