Second VGA screen detected but remains black.

Hello,

I have more or less the same issue :/

My laptop detects a VGA screen but I have no idea what screen it could be as it is not connected anywhere! (I’m “connected” to my box via Wi-Fi.) O.o

Is there any relation to the fact that my computer and my TV are from the same brand (TOSHIBA)?
Is it possible that it picks up the TV screen via “WIFI”?

If so, how can I display my PC in “extended” or “duplicated” mode on the TV? (I’ve already done it with a cable but I don’t know how to do it this way)

I’m using Windows 8… T_T

Thank you in advance for your responses :)

Hello everyone,

@lapinter, a VGA/DVI adapter, if it is passive (without electronics), cannot convert digital signals into analog signals. You would need a card or a box for that.

That’s probably why it doesn’t work for Grif51.

What is the purpose of this type of adapter then: in my opinion, it is to connect certain monitors that operate on DVI plugs with analog output on certain pins, which has existed.

Best regards

Hello,

It may be (but I am not a specialist) that detecting a DVI-Digital compliant screen disables the second output of the card (DVI-Analog), which then only works on the Digital pins. To verify this, one would need to measure the voltages at the second output when the recent monitor is connected.

Otherwise, if you had the possibility to connect two VGA monitors to the card, that would confirm the hypothesis.

Moreover, I understand that the VGA output is inactive on the motherboard when you use a recent monitor on the GPU/2DVI and becomes active when connecting a standalone VGA monitor.

So the question is: can we mix two monitors of different formats on these cards with two DVI-I outputs? It seems not, unless an user who has successfully operated this configuration contradicts that.

Hello

Isn't it the background that's black since you can navigate with your mouse?

It's stranger than that in my case:
I have this old monitor that only has a VGA input: http://www.ldlc.com/fiche/PB00047816.html
and my graphics card has two DVI outputs
The monitor worked fine with the VGA/DVI adapter (like http://www.amazon.com/StarTech-DVI-Cable-Adapter-DVIVGAMF/dp/B000067SOH which is indeed a DVI-I so it converts the analog DVI to VGA)

Then, I bought a newer monitor with a DVI input and connected it via DVI to my graphics card; it works without any problem.
However, when I also connect my old monitor to the 2nd output of the graphics card, this old monitor stays black (issue described by Grif51).
The strangest part is that if I switch back to my old setup (old monitor connected via adapter and new monitor unplugged), my old monitor doesn't work anymore!!! I don't understand anything!

The only way I've found to make it work is to connect it in VGA without an adapter to another graphics card (the one integrated on the motherboard) but unfortunately, that's not what I'm interested in.

If we solve this black screen issue, it will make a lot of people happy because I've seen dozens of posts on forums from guys who have the same problem.

Your hypothesis seems quite plausible and could then be generalized to many graphics cards!

In fact, the VGA output of the motherboard is active when I use a recent monitor on the DVI output of the graphics card. It gives me a dual-screen setup that works both under Windows 7 and Ubuntu 13.10 (except that I would like my old VGA monitor to benefit from the acceleration of my graphics card)!!

What I find strange is that previously, I only had my old VGA monitor connected to my graphics card's DVI via the adapter, and it worked; and now, even when I try that configuration again, my old monitor no longer works! It’s as if plugging in a digital DVI monitor to my graphics card has permanently deactivated the two DVI-analog outputs!

I've been working on this problem for more than 7 hours, and the only conclusion I can reach is:
I messed up the two DVI-analog outputs by connecting my DVI monitor. I really don’t see how, and the fact that both outputs no longer work makes me think it’s an internal component in the graphics card that is no longer functioning.
My two DVI outputs work perfectly in digital DVI mode.
I've tested the VGA cable, the adapter, and the VGA monitor which work like a charm (on another PC).

Thank you for your help, georges97.

Two VGA screens, but are the ports on your graphics card VGA or DVI+adapter?

Hello, I was on Windows 7 and my screen was working perfectly, then I switched to Windows 8.1, and my screen still works great. But then I noticed I couldn't access certain features with Windows 8.1, so I decided to go back to Windows 7, and now my screen won't turn on, but it is still detected. I've looked into whether it's a driver issue and updated them, but nothing changes; my screen still won't turn on. It's not my screen since I tried with another monitor, and it still didn't work. I would appreciate any help. Thank you.

I have the same issue: a DVI monitor connected to the DVI video card
+ a 2nd VGA monitor connected to the same video card but DVI (so adapter)
The VGA monitor stays black.

However, if I put a 2nd DVI monitor on the DVI port, it works!!!