I'm hoping you guys can help me out here. I recently built a HTPC (home theatre PC) for a friend and he was going to use his HDTV as the monitor. I didn't think anything of it since I hear about this working with lots of systems of this type, but when we hooked his up the picture is horridly blurry even at the lowest resolution (720p I think.) I'm great with computers but I know only what I need to know about tv's any help here would be appreciated. thanks.

Here's the thing, some HDTV's (LCD), only display resolutions like 1366 x 768, or what's called 720p (or 1080i for that matter). PCs usually don't display so well with those odd resolutions. Very likely, what your friend's seeing is due to this problem. The closest PC resolution comes to 720p is 1280 x 720, which kind of off scale in a 1366 x 768 screen. Also a lot of the "cheaper" HDTVs, don't allow you to adjust resolutions either, so end up hopelessly stuck with those resolutions.

The truth is HDTV is not a good computer display, even they are both LCDs and looks "similar" from outside. That's why PC monitors are still the best display for, what else, PCs.

thanks for the info, that's not what I was hoping to hear. it's not an LCD display though, it's a CRT, one of the lower grade HDTV's. to be specific it's a Toshiba 30hf85 30"widescreen. I've been searching around and haven't been able to find any help on the problem nor any information about it being a bad choice for a HTPC monitor so I'm really at a loss here.

CRT TV is even worse as computer monitor. What video cable you use to connect the PC to the TV?

that's what I figured as well, trying to talk him into an LCD since he's been wanting to upgrade anyway. using a DVI to HDMI adapter cable. the DVI on the computer is HDMI compatible according to the manufacturer so I don't think that's the problem either.

You can get decent results out of most LCD HDTVs. As the good Doctor pointed out, though, you definitely need to make sure the card is driving the TV at its native resolution. You may also need to fiddle with the settings on the TV. What connector are you using? VGA? DVI? HDMI? Personally I've had the best luck with VGA on my 40" 720P set...

Edit - just saw your reply. Try VGA if you can. What kind of video card is in the HTPC?

some good lcd tvs even have a dedicated computer port via dvi (but most new ones have the comp port on a vga plug which is stupid when they go on to have two HDMI ports)

I have expeianced both, my older lcd had a dvi comp port and it worked alot better than using HDMI just because the tv knew it was a comp and more options were avaliable at tv level(overscan and underscan not an issue) its moot point though as most setting can be changed at comp driver level

Have you tried 1920x1080? I used to have a 27" crt also but I used a component video cable to connect it, while it worked and the picture was great the tv would overscan. Keep on recommending a new tv

I'd try as many different resolutions AND refresh rates as possible within the range of the HDTV. You may find a non-standard match that provides a much better image, but may cut off some of the picture content at the edges, or you may end up with black borders around all sides of the image. In other words, you may have to sacrifice content or aesthetics for image quality. It's strictly trial and error at this point.

thanks for your input everybody. I've got him sold on a new tv and I'll make sure he lets me know so I can check it out. LCD's I know so I shouldn't have a problem there. if anybody has any more info to try and get it working with his current tv it would be much appreciated because it'll still be a while until he can get a new tv. I've already tried all the resolutions that are offered. the native resolution for the tv is 1080i I'm not sure what that would be in actual resolution sizes. it's running off of the onboard MCP chip it's an nforce 7100 which is about as good as most 256 graphics cards that can run HD displays from what I've been reading so I don't think graphics are the problem, feel free to disagree with me though.

On this computer I'm using an Acer 20" display. When the refresh rate is set to 70Hz, the display exhibits very fuzzy characters and there's a pattern to the fuzziness (e.g. every horizontal 4cm or so there's an even more fuzzy "line" of characters top-to-bottom on the screen) Note: the fuzziness is still there when displaying only graphics, but it's much easier to see when you project a regular pattern of data and your eye/brain 'knows' what it 'should' look like.

When I switch to 75Hz, the display shows the same information absolutely crystal clear over the entire display screen.

I'm hypothesizing either a display amplifer filter design or parts problem, or a video card clock instability or interference at certain settings.

It could be a cable impedance/stub issue, but I've used different cables (one very high quality) with the same results. It might even be a signal reflection issue at a connector/adapter interface at specific frequencies.


edit to add-the detailed fuzziness discussion

For some onboard video chip, you do need to select display type from BIOS. Depending on your BIOS, you can choose from TV / LCD, or even between cable type like Composite / VGA. One of my comp is like that.

thanks dr. peaceful, I didn't think to look in bios, I'll try that.