Question：I have a Dell Studio Hybrid PC running Windows Vista Home Premium attached to a Samsung LN52A750 LCD HDTV via HDMI. If I switch the TV away from the PC input and back, I lose the video signal... but only when Windows Media Center is running full screen.
This works fine:
- Turn the TV on.
- Switch to the PC input on the TV.
- Turn the PC on.
- Fire up Windows Media Center.
- Turn the PC off.
- Turn the TV off (or switch to a different input).
This also works fine:
- Turn the TV on.
- Switch to the PC input on the TV.
- Turn the PC on.
- Fire up Windows Media Center.
- Minimize Windows Media Center.
- Switch the TV to a different input but leave the PC on.
- Switch the TV back to the PC - you still see the PC's desktop.
- Turn the TV on.
- Switch to the PC input on the TV.
- Turn the PC on.
- Fire up Windows Media Center.
- Switch the TV to a different input but leave the PC on with Windows Media Center running full screen .
- Try to switch the TV back to the PC - no picture or sound is on the screen and the PC has to be fully rebooted to get sound/video back.
I came across this problem recently (after switching from a VGA/DVI connection to HDMI). I first came across it when the PC would go to sleep - the video signal would shut off and the TV would stop seeing the PC signal even once the PC woke up. I read a little online and thought this was something folks refer to as an "EDID handshake" problem. I thought just not letting the computer sleep (and not shutting off the video from the PC) would fix it, but I ran into another issue. Sort of a twist.
I was showing some friends how Media Center worked, I switched to the PC, showed them Windows Media Center, switched to a different input, then switched back to the PC (because I forgot to show something). The blue Media Center background appeared for a split second and the signal was instantly lost. I had to totally reboot to get the signal back.
I retried the experiment - fired up Media Center, switched the TV away from the PC, then switched it right back - same result. Signal lost, hard reboot.
I don't know how I stumbled upon it, but at one point I did the experiment with a twist. I fired up the computer, started Media Center, and minimized it. Then I switched the TV away from the PC and back... and the signal was still there. I did it again, and again, the signal was there. Turned the TV off and back on - signal still there. Then I maximized Media Center, switched the TV away from the PC, and when I came back... NO SIGNAL.
So: With Media Center full screen the signal gets lost, but when Media Center is minimized the signal stays.
I started thinking about how my recent use of the Media Center differed from previous times. Normally I use the Media Center, watch a movie or whatever, and then switch and do something else. I don't switch back and forth from the PC to something else and back. And every time I'd switched to the PC and it'd kept the signal, the screen saver had been on - the "Bubbles" screen saver.
Something I'd noticed with the "Bubbles" screen saver is that it sometimes brings the Windows task bar to the foreground so it appears "on top of" the full screen Windows Media Center. I usually switch the TV to the PC input before "waking the computer up" and getting the screen saver to go away.
Now I'm wondering if the lost signal has something to do with Windows Media Center. I [think I] know a little about how Windows works and the concept of running different "desktops." I wrote a screen saver a long time ago in unmanaged C++ and I remember there was some crazy stuff you had to do when writing a "windowless" application (like Media Center - there's no border around it when it goes full screen) and doing "overlays" like the "Bubbles" screen saver. I'm wondering if it has something to do with the standard Windows desktop working correctly but the Windows Media Center app full-screen "desktop" not working right.
I tried another experiment where I kept WMC full screen, let the TV lose the signal, and hit Win+D to minimize it and show the desktop. Then I switched the TV back. No luck - once the signal was lost, it was lost for good.
I have since been researching various answers. I read that setting the ACPI suspend mode to S3 would fix it, but it doesn't. I tried setting up a hotkey tied to a script that would change the display resolution to 640x480 and then change it back because I read that changing the resolution would refresh the signal - that didn't work.
Basically, I've found no alternative except to keep WMC minimized when it's not in use.
I'm going to try setting the "Bubbles" screen saver to 1 minute or something and see if that will at least let me switch the inputs on the TV after a minute of inactivity. Still, it'd be nice to know if there's some setting I'm missing.
Answer 1：I have a Dell Studio Hybrid PC running Windows Vista Home Premium attached to a Samsung LN52A750 LCD HDTV via HDMI. If I switch the TV away from the PC input and back, I lose the video signal... but only when Windows Media Center is running full screen.
This works fine:
- Turn the TV on.
- Switch to the PC input on the TV.
- Turn the PC on.
- Fire up Windows Media Center.
- Turn the PC off.
- Turn the TV off (or switch to a different input).
This also works fine:
- Turn the TV on.
- Switch to the PC input on the TV.
- Turn the PC on.
- Fire up Windows Media Center.
- Minimize Windows Media Center.
- Switch the TV to a different input but leave the PC on.
- Switch the TV back to the PC - you still see the PC's desktop.
- Turn the TV on.
- Switch to the PC input on the TV.
- Turn the PC on.
- Fire up Windows Media Center.
- Switch the TV to a different input but leave the PC on with Windows Media Center running full screen .
- Try to switch the TV back to the PC - no picture or sound is on the screen and the PC has to be fully rebooted to get sound/video back.
I came across this problem recently (after switching from a VGA/DVI connection to HDMI). I first came across it when the PC would go to sleep - the video signal would shut off and the TV would stop seeing the PC signal even once the PC woke up. I read a little online and thought this was something folks refer to as an "EDID handshake" problem. I thought just not letting the computer sleep (and not shutting off the video from the PC) would fix it, but I ran into another issue. Sort of a twist.
I was showing some friends how Media Center worked, I switched to the PC, showed them Windows Media Center, switched to a different input, then switched back to the PC (because I forgot to show something). The blue Media Center background appeared for a split second and the signal was instantly lost. I had to totally reboot to get the signal back.
I retried the experiment - fired up Media Center, switched the TV away from the PC, then switched it right back - same result. Signal lost, hard reboot.
I don't know how I stumbled upon it, but at one point I did the experiment with a twist. I fired up the computer, started Media Center, and minimized it. Then I switched the TV away from the PC and back... and the signal was still there. I did it again, and again, the signal was there. Turned the TV off and back on - signal still there. Then I maximized Media Center, switched the TV away from the PC, and when I came back... NO SIGNAL.
So: With Media Center full screen the signal gets lost, but when Media Center is minimized the signal stays.
I started thinking about how my recent use of the Media Center differed from previous times. Normally I use the Media Center, watch a movie or whatever, and then switch and do something else. I don't switch back and forth from the PC to something else and back. And every time I'd switched to the PC and it'd kept the signal, the screen saver had been on - the "Bubbles" screen saver.
Something I'd noticed with the "Bubbles" screen saver is that it sometimes brings the Windows task bar to the foreground so it appears "on top of" the full screen Windows Media Center. I usually switch the TV to the PC input before "waking the computer up" and getting the screen saver to go away.
Now I'm wondering if the lost signal has something to do with Windows Media Center. I [think I] know a little about how Windows works and the concept of running different "desktops." I wrote a screen saver a long time ago in unmanaged C++ and I remember there was some crazy stuff you had to do when writing a "windowless" application (like Media Center - there's no border around it when it goes full screen) and doing "overlays" like the "Bubbles" screen saver. I'm wondering if it has something to do with the standard Windows desktop working correctly but the Windows Media Center app full-screen "desktop" not working right.
I tried another experiment where I kept WMC full screen, let the TV lose the signal, and hit Win+D to minimize it and show the desktop. Then I switched the TV back. No luck - once the signal was lost, it was lost for good.
I have since been researching various answers. I read that setting the ACPI suspend mode to S3 would fix it, but it doesn't. I tried setting up a hotkey tied to a script that would change the display resolution to 640x480 and then change it back because I read that changing the resolution would refresh the signal - that didn't work.
Basically, I've found no alternative except to keep WMC minimized when it's not in use.
I'm going to try setting the "Bubbles" screen saver to 1 minute or something and see if that will at least let me switch the inputs on the TV after a minute of inactivity. Still, it'd be nice to know if there's some setting I'm missing.
Answer 2：
Hello Travis,
Thank you for posting. In my experience, I've seen a lot of HDMI issues with some brands of TVs (Samsung and Visio mostly). I can offer one other possible solution for you. You can try to totally disconnect the HDMI cable and then reconnect it to both PC and TV. It should have the same effect as restarting your computer.
Please let me know how it works out. I'm really interested in your results.
Zack
Microsoft Answers Support Engineer Visit our Microsoft Answers Feedback Forum and let us know what you think.
Answer 3：Sorry it's taken a while to get back; I wanted to try a bunch of stuff and see if I could solve it. So far, no luck.
Unplugging/replugging the cable doesn't work. Once the signal is lost, it's lost for good. You have to reboot. I also tried switching the cable around (swapping ends - plug the end from the TV into the computer and vice versa) but that didn't change anything, either. (I didn't think it would, but I read on some forums that it did something for someone and figured it couldn't hurt to try.)
I tried connecting the computer to the TV twice - via both the HDMI connection and a DVI connection - and setting the HDMI connection as the primary monitor and the DVI connection as the secondary. I read on another forum that it could wake the TV up if you switch to the DVI connection and back to the HDMI connection. That didn't do anything but mess up my display settings.
I've tried getting the HDMI failure to happen during other programs running and Media Center isn't running - Internet Explorer, command prompt, etc. - but it only happens when Media Center is running full screen. It even seems to be fine if Media Center is running in a window. The only time I've seen a problem is with Media Center running full screen.
So, since the whole point of the PC right now is to boot up and go right into Media Center, the only solution I've found is to keep the computer from ever going to sleep and to keep the Bubbles screen saver running starting at 1 minute. As long as I don't switch away from Media Center and back before the screen saver has started, I won't lose the signal. I've run it for almost a month straight, never losing signal, with the Bubbles screen saver.
The fact that Bubbles saves me from losing the signal is why I was thinking about the different desktop modes of Windows. Again, I could be just spouting random words that have nothing to do with anything, but that's the first thought in my head.
Something else I noticed while experimenting (which I also noticed originally, but still seems kinda fishy to me) - if I switch away from Media Center and switch back before Bubbles starts up, Media Center actually appears for just a fraction of a second and then disappears , replaced by a black screen and the TV telling me it can't find a signal. I don't know if what I was seeing was something shown to me out of some sort of video buffer on the TV or if the computer really was broadcasting the image of Media Center and then the TV, during some sort of handshake, disabled the video or something.
I've not had any HDMI problems connecting my Xbox 360 or my Playstation 3 to the same TV - just the Dell Studio Hybrid - so while it may be that Samsung TVs have HDMI issues, the Xbox 360 and PS3 teams seem to have figured out the way around it. That leads me to believe, perhaps incorrectly, that a driver or software update might be able to fix this issue.
Let me know if there's something else I might be able to try, short of upgrading to Windows 7 or something. (Happy to try stuff out, just not looking to do something that can't be rolled back via System Restore.)
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