Friday, June 25, 2010

The joys of connecting a PC to a TV

About a year ago I decided to build a small PC to run Beyond TV Link for the TV in the living room.  That's  a secondary TV for us as the main TV with the HTPC connected to it is in the family room.  I had previously had the old HTPC connected there when I upgraded it a couple of years ago, but the motherboard died and I was just getting around to replacing it.  Of course, after I built the new PC it didn't get connected to the TV right away, instead serving as a test PC for Windows 7 and a few Linux distros and it even served as a kitchen PC for a while before making it to its new home a few months ago.

The old PC was connected to the TV via the VGA port since it used an older video card (a Radeon 9800 SE) that only had VGA output.  That worked fine while it lasted so I didn't expect any issues with the new PC.  The TV, by the way is an Insignia 26" 720p LCD that's about two and a half years old now.

The new PC or "Link Box" as its referred to in the Beyond TV community used a Zotac GF9300-D-E mini-ITX motherboard that has integrated NVidia 9300 graphics and includes HDMI output.  When I originally connected it to the TV I used HDMI.  I was rather disappointed to find out that the TV didn't have a mode that eliminates overscan from the picture.  I used NVidia's correction tool to create a custom resolution that fit within the viewable area of the screen and called it good.  I wasn't terribly happy about it, but it worked and the BTV Link picture was acceptable.  The bigger issue with is is that I needed to always remember to turn the TV on and set the input before turning on the PC.  Otherwise, the output would never show up on the TV.

This was all good enough until my daughter wanted to watch a Blu-Ray movie in the living room last night and I realized I hadn't reinstalled Power DVD with the last OS refresh.  So, I went ahead and installed Power DVD and that's when the fun started.  Power DVD wouldn't run because it requires a minimum screen resolution of 1024x768 and the custom resolution I was using to make the picture fit was less than that.  I may have been able to bump that up, but then the overscan would have put the task bar completely off the screen and that wouldn't have been very user-friendly.

As an aside, why 1024x768?  The standard 720p resolution is 1280x720 and apparently that's the highest progressive resolution my TV would accept over HDMI, so is Power DVD not meant to be used with TVs instead of computer monitors?

Be that as it may, I know the TV's native resolution is 1360x768, and that resolution satisfies Power DVD's requirements.  So, I dug out the old VGA and audio cables and connected the computer to the VGA input on the TV.  At least I wouldn't need to deal with the overscan issue that way.  I was certain this would work, after all, it worked fine with the old computer.  But it didn't.

When I rebooted the computer now with VGA instead of HDMI everything looked good initially.  I saw the boot splash screen, then the Windows startup animation just fine.  When it was time for the Windows desktop to show up, though, the screen went blank.  Then the TV's "Missing Input" indicator came up.  I tried again.  Same result.

I connected a second monitor to the PC to check the resolution and settings.  Lo and behold, with the other monitor connected, the TV works fine.  It doesn't even matter if the TV or the monitor is the primary display.  Weird.  Apparently there's some sort of handshake that's not happening between the PC and the TV.  I've heard of issues like that with HDMI, but never VGA.

So, I decided to try connecting both the VGA and HDMI inputs to the TV.  At first that didn't help.  Then I set the option to clone the picture to both monitors in Windows.  Now I can use the VGA input on the TV with no overscan and it works just fine.  It doesn't even matter which order I turn on the TV and PC any more.

Of course, the downside is that  now I need to run 3 cables from the PC to the TV and waste an HDMI port, but I wasn't using it for anything anyway.

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