DVI and VGA? - Tilted Forum Project Discussion Community

Jinn · 12-11-2006, 10:57 AM

So - I've recently been having trouble with VGA and DVI. My dad bought a new computer whose video card was equipped only with two DVI plugs on the back of it. Nicely enough, it came with these dvi-male to vga female converters. I presume that they are designed to allow you to hook up a VGA (old CRT or LCD) device to the DVI ports.

And yet, no matter how many VGA cables I tried, and no matter which of the three DVI to VGA plugs I used, I couldn't get a signal on the monitor. Eventually, I just gave him my DVI cable and had him hook up DVI from LCD to DVI on Video card. It worked.

Unfortunately, on a new build for my girlfriend, she doesn't have an LCD. Her CRT only accepts VGA, and her new video card only has two DVI ports. I'm afraid that again the plugs won't work, but I'll be much more SOL without an LCD.

Anyone explain to me how these are supposed to work?

The video card is http://www.newegg.com/Product/Produc...82E16814161043

Dilbert1234567 · 12-11-2006, 07:10 PM

Make sure you connect both the converter and the monitor before you turn it on, i know on my system, you can't add the converter after the system is on.

Give that a try maybe.

Mondak · 12-12-2006, 11:08 AM

If Dilbert's suggestion doesn't do it, there are a couple other options. Some (particularly older) video card drivers don't automatically switch to VGA and you have to go into the settings of the video card and tell the card to send a VGA signal or a DVI Signal. I would think that card would have no trouble but I don't know. Poke around the settings and see what you find.

By the way - if you take a look at an LCD monitor, you should see a big difference between the DVI connection and the VGA connection. if not there are some other things wrong (like running the LCD below it's rated resolution) that are making it look not as sharp as it should.

Jinn · 12-12-2006, 12:00 PM

It seems that it's an issue of either the LCD not receiving the "wake" message when the computer boots, or the LCD not knowing I have the VGA plug (as opposed to the DVI plug) selected.

If I plug the VGA from a CRT to the VGA on the video card, the computer boots and the monitor crackles and "wakes," displaying the POST.

If I plug the VGA from a CRT into the VGA->DVI plug and then into the DVI port on the video card, the computer boots and the monitor crackles and "wakes," displaying the POST.

And yet if I plug the VGA from the LCD into the video card, nothing.
Likewise, if I plug the VGA from the LCD into the VGA->DVI plug, nothing.

There's an "input select" button on the LCD, but it seems like I can only change it when it has a signal. I tried unplugging and replugging the monitor, hoping it would "sense" that it was plugged on the VGA port, but nothin.

n0nsensical · 12-12-2006, 05:06 PM

DVI to VGA converters are basically wires. DVI-I includes digital and analog signals; the converters take the analog signals and connect them to the appropriate VGA pins. If the card isn't outputting the analog signals it won't work, but since the CRT you tried is obviously getting the signal I don't think that's the problem. You might be on the right track with the monitor settings.. I have a X850 with 2 DVI outputs and 2 monitors that only take VGA and I've never had a problem with the card.

Also, this is pretty simple, but have you tried plugging the monitor into the other output? I think my card only uses one specific output unless you've configured it to use two monitors, i.e. if you plug a single monitor into the wrong output you get nothing.

Jinn · 12-13-2006, 10:32 AM

On the x800 XL AGP, one is VGA, one is DVI. So I have to plug them to certain ones. The DVI is DVI-I, so I know the convertor should IN THEORY work.

DaElf · 12-17-2006, 01:45 AM

I have that same card except PCI-E. Sometimes I have to mess with the monitor cord or else I get "no signal" only on cold boot. I also at times see distortion from the connector getting a shotty connection. A little jiggle jaggle of the monitor cord usually fixes this. This probably isn't of any use to you but you're not the only one having to deal with messed up connectors.

12-11-2006, 10:57 AM	#1 (permalink)
Jinn Lover - Protector - Teacher Location: Seattle, WA	DVI and VGA? So - I've recently been having trouble with VGA and DVI. My dad bought a new computer whose video card was equipped only with two DVI plugs on the back of it. Nicely enough, it came with these dvi-male to vga female converters. I presume that they are designed to allow you to hook up a VGA (old CRT or LCD) device to the DVI ports. And yet, no matter how many VGA cables I tried, and no matter which of the three DVI to VGA plugs I used, I couldn't get a signal on the monitor. Eventually, I just gave him my DVI cable and had him hook up DVI from LCD to DVI on Video card. It worked. Unfortunately, on a new build for my girlfriend, she doesn't have an LCD. Her CRT only accepts VGA, and her new video card only has two DVI ports. I'm afraid that again the plugs won't work, but I'll be much more SOL without an LCD. Anyone explain to me how these are supposed to work? The video card is http://www.newegg.com/Product/Produc...82E16814161043 __________________ "I'm typing on a computer of science, which is being sent by science wires to a little science server where you can access it. I'm not typing on a computer of philosophy or religion or whatever other thing you think can be used to understand the universe because they're a poor substitute in the role of understanding the universe which exists independent from ourselves." - Willravel

12-11-2006, 07:10 PM	#2 (permalink)
Dilbert1234567 Devils Cabana Boy Location: Central Coast CA	Make sure you connect both the converter and the monitor before you turn it on, i know on my system, you can't add the converter after the system is on. Give that a try maybe. __________________ Donate Blood! "Love is not finding the perfect person, but learning to see an imperfect person perfectly." -Sam Keen

12-12-2006, 11:08 AM	#3 (permalink)
Mondak Industrialist Location: Southern California	If Dilbert's suggestion doesn't do it, there are a couple other options. Some (particularly older) video card drivers don't automatically switch to VGA and you have to go into the settings of the video card and tell the card to send a VGA signal or a DVI Signal. I would think that card would have no trouble but I don't know. Poke around the settings and see what you find. By the way - if you take a look at an LCD monitor, you should see a big difference between the DVI connection and the VGA connection. if not there are some other things wrong (like running the LCD below it's rated resolution) that are making it look not as sharp as it should. __________________ All truth passes through three stages: First it is ridiculed Second, it is violently opposed and Third, it is accepted as self-evident. ARTHUR SCHOPENHAUER (1788-1860)

12-12-2006, 12:00 PM	#4 (permalink)
Jinn Lover - Protector - Teacher Location: Seattle, WA	It seems that it's an issue of either the LCD not receiving the "wake" message when the computer boots, or the LCD not knowing I have the VGA plug (as opposed to the DVI plug) selected. If I plug the VGA from a CRT to the VGA on the video card, the computer boots and the monitor crackles and "wakes," displaying the POST. If I plug the VGA from a CRT into the VGA->DVI plug and then into the DVI port on the video card, the computer boots and the monitor crackles and "wakes," displaying the POST. And yet if I plug the VGA from the LCD into the video card, nothing. Likewise, if I plug the VGA from the LCD into the VGA->DVI plug, nothing. There's an "input select" button on the LCD, but it seems like I can only change it when it has a signal. I tried unplugging and replugging the monitor, hoping it would "sense" that it was plugged on the VGA port, but nothin. __________________ "I'm typing on a computer of science, which is being sent by science wires to a little science server where you can access it. I'm not typing on a computer of philosophy or religion or whatever other thing you think can be used to understand the universe because they're a poor substitute in the role of understanding the universe which exists independent from ourselves." - Willravel

12-12-2006, 05:06 PM	#5 (permalink)
n0nsensical Junkie Location: San Francisco	DVI to VGA converters are basically wires. DVI-I includes digital and analog signals; the converters take the analog signals and connect them to the appropriate VGA pins. If the card isn't outputting the analog signals it won't work, but since the CRT you tried is obviously getting the signal I don't think that's the problem. You might be on the right track with the monitor settings.. I have a X850 with 2 DVI outputs and 2 monitors that only take VGA and I've never had a problem with the card. Also, this is pretty simple, but have you tried plugging the monitor into the other output? I think my card only uses one specific output unless you've configured it to use two monitors, i.e. if you plug a single monitor into the wrong output you get nothing. Last edited by n0nsensical; 12-12-2006 at 05:33 PM..

12-13-2006, 10:32 AM	#6 (permalink)
Jinn Lover - Protector - Teacher Location: Seattle, WA	On the x800 XL AGP, one is VGA, one is DVI. So I have to plug them to certain ones. The DVI is DVI-I, so I know the convertor should IN THEORY work. __________________ "I'm typing on a computer of science, which is being sent by science wires to a little science server where you can access it. I'm not typing on a computer of philosophy or religion or whatever other thing you think can be used to understand the universe because they're a poor substitute in the role of understanding the universe which exists independent from ourselves." - Willravel

12-17-2006, 01:45 AM	#7 (permalink)
DaElf Tilted Location: Washington	I have that same card except PCI-E. Sometimes I have to mess with the monitor cord or else I get "no signal" only on cold boot. I also at times see distortion from the connector getting a shotty connection. A little jiggle jaggle of the monitor cord usually fixes this. This probably isn't of any use to you but you're not the only one having to deal with messed up connectors. __________________ I'm sitting at my desk right now waiting for you to reply to the above message.