Second DVI Port Detecting Montitor, But Not Displaying

[Khalos]

Hello Everyone

Suddenly my second monitor stopped working.

It seems to be correctly detecting when I plug the second monitor in. It detects the make/model, resolution, etc but it doesn't actually display anything.

I tried swapping the two cords, and then the second monitor works, but the first does not. This confirms that both monitors work, and that both cords work.

Usually my boot screen appears mirrored on both monitors, but that's not happening either, so it's happening before Windows (8.1) even loads, so that rules out a driver issue, correct?

I'm really confused here, everything was working fine yesterday. Did my DVI port suddenly die, or is there something else I'm missing.

The GPU is a AMD Radeon HD 6870.

Any help would be appreciated.

Thank you

 

[Shaun o]

One way to confirm it.
What ever monitor worked first with the original cable used.
And you are using both DvI ports of the card.
Swap it over to the other Dvi.

If you get no signal then you know it`s the cable.
Be aware that most cards with two Dvi ports have two types of Dvi.

One can be for a Dvi-D only and will not take a Dvi-i or analog wired cable.
And the other Dvi can be a Mix to take Digital/ analog Dvi cables.

Or just Analog on its own.

 

[Khalos]

One way to confirm it.
What ever monitor worked first with the original cable used.
And you are using both DvI ports of the card.
Swap it over to the other Dvi.

If you get no signal then you know it`s the cable.
Be aware that most cards with two Dvi ports have two types of Dvi.

One can be for a Dvi-D only and will not take a Dvi-i or analog wired cable.
And the other Dvi can be a Mix to take Digital/ analog Dvi cables.

Or just Analog on its own.

It appears the only thing that makes a difference is the actual port. If I swap the ports used, the secondary works but the primary doesn't. If I swap cords, it's still just whatever cord/monitor are in the original DVI port on the gpu.

Just to note, neither the monitors, cords nor GPU are new. They all worked yesterday, so it shouldn't be an analog/digital issue.

Thanks for the suggestion though.