Rather confusing monitor problem

Merlin5 · 4 Nov 2013 at 19:36

A few weeks ago, my friends Relisys monitor wasn't displaying anything, it kept showing a small icon meaning PC not connected. Her monitor socket appears to be DVI-I dual link (that's the only socket available, no VGA) and her PC only had a VGA connector on a graphics port attached to her motherboard, no graphics card as such. Her cable is actually DVI-A to VGA. I then tested if her monitor was at fault by connecting her VGA cable to my laptop while connected to her monitor. Her monitor displayed everything fine, and my laptop displayed the same. Cut a long story short, 2 weeks ago she took her PC to a local shop who told her the motherboard was dead. So he's put another PC together for her, including a graphic card with both VGA and DVI-I dual link connectors.

We took it back to her place, I connected it up to her Relisys monitor DVI-I to VGA on her card using her DVI-A/VGA cable and all was well, everything came up on screen. She used the PC for a few hours then shut it down. Today was the first time she'd booted the PC up since I left her place 2 weeks ago, and the icon appeared again on her screen saying PC not connected. I could see the hard drive activity light flickering, so knew the PC was ok. Took PC to the shop who hooked it up to his VGA monitor and everything displayed fine.

I've now taken her PC and monitor to my place. I connected my Samsung monitor to her PC with my DVI-D dual link cable and that worked fine. I then connected her monitor back again with my DVI-D cable and her monitor flashes a few times then says 'INVALID MODE'. I then put her VGA/DVI-I cable back and it goes back to the PC not connected icon.
Finally, connected her VGA/DVI-I cable to my laptop again and it still works fine, displaying everything on both her Relisys and my laptop screen.

So I thought her VGA/DVI-A cable was faulty but it doesn't appear to be, and her monitor works too. So, I cannot figure out why it was all working when we first got the new PC back and now it keeps showing that icon. Any thoughts?

Teal · 4 Nov 2013 at 20:34

I suspect her monitor only supports DVI-A or is set to only use DVI-A which is why your DVI-D cable did not work.

It is also possible that her PC is defaulting to the DVI output instead of VGA, check the BIOS and see what is set there ...

The correct DVI cable would probably be the right solution though.

Merlin5 · 4 Nov 2013 at 21:06

Teal said:
I suspect her monitor only supports DVI-A or is set to only use DVI-A which is why your DVI-D cable did not work.

It is also possible that her PC is defaulting to the DVI output instead of VGA, check the BIOS and see what is set there ...

The correct DVI cable would probably be the right solution though.

Yep, I agree, I think the correct cable would probably sort it.
It's a good point about the BIOS. Maybe I should connect my monitor again so I can see her PC and check her BIOS and see if I can set it to VGA. Still don't get why it displayed ok 2 weeks ago but not now. Also, my DVI-D cable worked ok with my monitor going into her DVI-I graphics card socket, which is why I thought the DVI-D cable would also work in the DVI-I socket on her monitor. But as you say, if her monitor is set to DVI-A that would make sense. The only thing that is DVI-A is her cable, as her sockets are both DVI-I.

This is the socket on the back of her monitor, which shows DVI-I dual link. I don't know what the yellow socket is.

Teal · 4 Nov 2013 at 21:23

Do you know exactly which monitor she has?

It is not uncommon to see a universal socket fitted to a device so you can plug any DVI cable into it, but it does not mean that it will actually make use of dual-link for example.

Does her monitor have speakers? If so, that 'yellow' socket is probably audio in (usually green)

Merlin5 · 4 Nov 2013 at 23:57

Teal said:
Do you know exactly which monitor she has?

It is not uncommon to see a universal socket fitted to a device so you can plug any DVI cable into it, but it does not mean that it will actually make use of dual-link for example.

Does her monitor have speakers? If so, that 'yellow' socket is probably audio in (usually green)

It's a Relisys 19" TL970D LCD.
http://britaincloud.co.uk/51917-relisys-tl970d.html

Yeah apparently it does have built in speakers so you're probably right about the yellow socket. It also says input connectors DVI-D, DVI-A.

I seem to have got it fixed now after some messing around. Connected both my monitor and hers simultaneously. Hers using DVI on monitor and VGA on graphics card, and mine just DVI to DVI. It's like my monitor seemed to jump start hers. Nothing showed on hers while mine was displaying the boot process. Once it got to the desktop, her monitor then displayed it too, but with a black border to the left on hers. I then disconnected my monitor and hers then went full screen. In her Nvidia control panel (her card is an 8400 GS) it says Connector: VGA-PC Display. Resolution: 1280 x 1024 (native). That's the top res for the monitor. On rebooting, there was a 3 inch black border on the left pushing the desktop across to the right. In the end, the highest res on VGA where I'm able to keep it full screen is 1152 x 864. As soon as I set the next highest res (1280 x 720) it letterboxes with black border top and bottom. But I think this is fine for her needs now.