TV doesn't automatically show signal from Windows Media Center

Question

I have Windows Media Center running on Win7 RTM with a GIGABYTE GA-MA78GM-S2H motherboard. The integrated video card is an ATI Radeon HD 3200.

It's connected to a Sony Bravia KDL-46XBR4 tv via HDMI cable.

When I turn both on at the same time, I get great sound and video.

The issue is that when I leave the computer on and turn off the TV, the TV does not display the video or audio signal when I turn the TV back on.

• The computer is set to never turn of the display.
• I've tried different HDMI cables - I have two, a brand-name and a no-name cable.
• I've tried different HDMI input ports - all have the same behavior.
• I've tried cycling the TV to switch to different inputs and back, no dice
• I've tried Ctrl+Alt+Delete - no dice.
• I can confirm that the computer is running by connecting via remote desktop.

Only two things seem to work:

• shutdown and startup
• sleeping the computer and starting up.

Neither of those "solutions" work well, as I'm looking for a pure couch potato solution.

Answer 1

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.

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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...

Answer 2

Looks like the EDID is the problem. When you turn your TV off, the EDID of your computer video source is lost (since it is in memory in the TV).

According to wikipedia:

Extended display identification data (EDID) is a data structure provided by a computer display to describe its capabilities to a graphics card. It is what enables a modern personal computer to know what kind of monitor is connected. EDID is defined by a standard published by the Video Electronics Standards Association (VESA). The EDID includes manufacturer name and serial number, product type, phosphor or filter type, timings supported by the display, display size, luminance data and (for digital displays only) pixel mapping data.

The EDID is often stored in the monitor in a memory device called a serial PROM (programmable read-only memory) or EEPROM (electrically erasable PROM) and is accessible via the I²C bus at address 0x501.

When you turn your TV off, this ID is lost and causes the 'agreement' between the PC and TV to be lost as well. There are devices that can store this ID, such as this (note: I have no experience with these devices).

Answer 3

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.

Answer 4

As I noted in my reply to Omar

My display is blank when I turn on my HDTV connected to Media Center

Sometimes the "three finger salute" can fix this.

Answer 5

I have had a similar issue with my Apple TV. It has to do with HDMI handshaking. The TV "wakes up" but doesn't immediately notice that there is a signal. It seems to be different from device to device. I had to switch my Apple TV to component when I bought a new cable box. The cable box never has any HDMI issues.

If I'm correct, you should also see signal appearing after cycling the TV input a few times (like from HDM1 to HDMI2 to Component, etc, until you get back to your Media Center HDMI input again).

Answer 6

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?

Answer 7

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.

Answer 8

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.