Question VGA doesn t work but hdmi does?

Apr 8, 2020
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So, i have quite an issue that i can t resolve, basically, what i m trying to do is connect my pc to a vga monitor, either through the vga port on the motherboard, either with a DVI to VGA adaptor put on the video card. The issue is that no matter what port i use, cable or monitor, the pc won t display any vga signal. What i did find is that if i change the video card, the display works from the vga port on the mobo and the one on the older video card.
Specs are as follow:
pentium E5500
2gb ddr3 ram
Ati radeon hd 5870
Biostar G41D3 mobo
If i switch my video card to the radeon hd 5450 there is an output, but if i put my better video card that i want to use, the radeon hd 5870 it doesn t show.
Also, if i try to connect to another monitor via hdmi, there is an output and it works, but i want to use the vga monitor as it s the one that is actually mine.
 

MadsModsat

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Oct 10, 2019
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One thing I see which could possibly be an issue when I read your post, is the version of the DVI port on the two different graphics cards.

If the slower GPU has DVI-I and the other has DVI-D, this would mean that you can use a passive DVI to VGA adaptor on one card, but need an active adaptor for the other card.

However this doesn't explain why your motherboard VGA port only works with VGA when one card is installed and not the other

But DVI-I is carrying both analogue and digital signal, which is why you can use a passive adaptor for VGA.

DVI-D is digital only, and you need an active adaptor to convert from the digital video signal to the analogue VGA signal.

The fact that there's a HDMI signal on one graphics card, but no DVI/VGA from the same card, could indicate that the signal type is the problem, which would have different requirements for the adaptor - passive vs. active.

On some graphics cards from that era, there were 2 DVI ports, one of them being DVI-I and the other being DVI-D. So in order to use VGA on a card which supported both standards, it would be important to use the DVI-I port for VGA

The graphics cards are from a time, where analogue support was declining and some manufacturers used very different outputs for their various graphics card models, if I remember correctly

But I'm a bit confused about the issues with onboard VGA, so there could be something else going on.

But it only takes a minute to look at both graphics cards to verify whether they are DVI-I or DVI-D, and if that's not the problem, at least that's one item less on the list of possible causes
 
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Apr 8, 2020
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what the make and model of the psu?
got the pcie power cable to the HD 5870?
The psu doesn t matter as i have used this psu and videocard before on another sistem and they both worked
And i can confirm that the gpu has enough power from the psu and the cables are good
 
Apr 8, 2020
11
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One thing I see which could possibly be an issue when I read your post, is the version of the DVI port on the two different graphics cards.

If the slower GPU has DVI-I and the other has DVI-D, this would mean that you can use a passive DVI to VGA adaptor on one card, but need an active adaptor for the other card.

However this doesn't explain why your motherboard VGA port only works with VGA when one card is installed and not the other

But DVI-I is carrying both analogue and digital signal, which is why you can use a passive adaptor for VGA.

DVI-D is digital only, and you need an active adaptor to convert from the digital video signal to the analogue VGA signal.

The fact that there's a HDMI signal on one graphics card, but no DVI/VGA from the same card, could indicate that the signal type is the problem, which would have different requirements for the adaptor - passive vs. active.

On some graphics cards from that era, there were 2 DVI ports, one of them being DVI-I and the other being DVI-D. So in order to use VGA on a card which supported both standards, it would be important to use the DVI-I port for VGA

The graphics cards are from a time, where analogue support was declining and some manufacturers used very different outputs for their various graphics card models, if I remember correctly

But I'm a bit confused about the issues with onboard VGA, so there could be something else going on.

But it only takes a minute to look at both graphics cards to verify whether they are DVI-I or DVI-D, and if that's not the problem, at least that's one item less on the list of possible causes

What you re saying may be correct, but like 1 year ago i used this very video card and adapter, but different mobo ram and processor, so i m pretty sure they re compatible
 

MadsModsat

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Oct 10, 2019
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You didn't mention which configuration this has previously been working in, so from the details in your first post, the probable cause that I could think of, was the types of signal involved.

Now that you in addition to the initial post can reveal you have had it working with the same adaptor, obviously that solution lies elsewhere.

But I can't take information into account, that I didn't have when I wrote my reply.

Had I known that information, I wouldn't have posted, since I don't know what else could be causing these issues you are struggeling with.

Motherbord and RAM is not relevent in the matter of DVI-I vs. DVI-D on a dedicated graphics card, but it is important with regards to integrated graphics outputs, of course.

I hope you find a solution to the problem shortly
 
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Apr 8, 2020
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You didn't mention which configuration this has previously been working in, so from the details in your first post, the probable cause that I could think of, was the types of signal involved.

Now that you in addition to the initial post can reveal you have had it working with the same adaptor, obviously that solution lies elsewhere.

But I can't take information into account, that I didn't have when I wrote my reply.

Had I known that information, I wouldn't have posted, since I don't know what else could be causing these issues you are struggeling with.

Motherbord and RAM is not relevent in the matter of DVI-I vs. DVI-D on a dedicated graphics card, but it is important with regards to integrated graphics outputs, of course.

I hope you find a solution to the problem shortly

Thank you anyways for answering to this, i really don t know what could be causing this, as i ve been trying for the past 2 days..
I can safely say it s not the cpu s problem either as i tried replacing it with a pentium e3300 instead, but with no results unfortunately....
So my only guesses would be that it s a problem with compatibility from the video card itself, and maybe even the adaptor.. i really have no way of testing this as i don t have a dvi cable or monitor...
What i can say aswell is that i ve seen just a few hrs ago that now the vga port on the mobo doesn t output anything, from either video cards, but when trying the vga from the older one it works, when i try from the newer one WITH the adapter it doesn't
So my only choice now is to either try different combinations and fiddle with them until they may or may not function, or simply replace my monitor with a newer one that has hdmi, and use that port as i know it to be good.
What might also work is a hdmi to vga adapter, but i honestly don t know what to say at 3:13am... i also need to upgrade the ram from 2gb to 8gb soon, maybe even the processor to a core 2 quad.. maybe..
 

MadsModsat

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Oct 10, 2019
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I still suspect you are using the wrong adaptor, like I said in my first post. DVI-I and DVI-D requires different adaptors

But since you quite clearly said that it couldn't be the problem, because it has worked previoulsy, I'm surprised you are now having second thoughts.

But like I said, it only takes a minute er two, to find out if both cards has DVI-I, or if one of them perhaps has DVI-D

If you've already spent two days troubleshooting the problem, why not take a minute to conclusively rule the adaptor out by checking what DVI versions you are working with?

It is often stamped in the metal above the DVI port what kind it is, and if it isn't, it is possible to find the information online without too much effort.

But if you are completely sure the adaptor can't be the problem as you initially said, because it has been working previously, then you'll have to decide yourself if it is worth checking up on

- I'm certainly not saying it definately IS the problem, but it is not impossible either
 
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I can t tell if the hd 5870 has dvi-i or dvi-d, it doesn t say on the card and i can t find anything online about this, and about the adapter, it s a Myria, and the code for it is MY8716 if you want to look it up online, but online it only says DVI 24+5 pin father - VGA 14 pin mother
So, could you help me in finding out their compatibility? The card is an ati radeon 5870 from asus
 
Apr 8, 2020
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Yea... but still, why would it do that? I mean, BOTH dvi ports are dvi i, the vga cable and monitor are known good...
At this point i am farely certain that the issue is the video card, because i haven t mentioned this, but in hopes that i might fix it i swapped another mobo ram and processor, (i was going to do that anyways) and the problem still lies...
 

MadsModsat

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Oct 10, 2019
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If both cards are DVI-I, the adaptor you use is fine, it seems that the adaptor can be ruled out as the cause of the problem.

If THIS is you graphics card, the one that doesn't display other than HDMI, it does indeed have DVI-I

If possible, you could always ask a friend or a family member, if they have an adaptor you can borrow as a quick test, to completely rule out any other adaptor issues

Also, it could possibly be an idea to try a different VGA cable, eventhough it seems to work some of the time. But you never know, maybe it is worth double checking

But I can't really say I have any other suggestions for you to try. The only thing that crossed my mind as a potential problem, was signal type - partially due to the time period the cards are from
 
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Yea, the cable is known good as i tested it, i don t have another adapter as this is the one i bought to use it, and yes, that is my card... i have no ideea..
 
Apr 8, 2020
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Whoah, while trying different combinations, i just saw, if i plug the hdmi in, from the TV, in the corner instead of saying hdmi 3 (the 3rd slot) it said DVI 3
 
Apr 8, 2020
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Ok, i have fixed it, somehow, i don t know how i tried plugging the hdmi and vga in the tv, and when i did and switched from hdmi to PC which is vga, it worked, i put it now on my monitor and it now works,
So it s solved.
 
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