Hello Elijah.

I tried both your suggestions, and it appears I got contradictory results.

First, I tried to use the "bad" monitor without the good one on the original computer. It still did not work. I have an ATI Radeon HD 3400 Series display adapter on that computer. (I uninstalled and re-installed the driver, but that did not solve the problem.)

I then tried the "bad" monitor on a second computer ... and it did work. The brightness of the screen briefly flickered once, but then it worked fine. I have an NVIDIA GeForce 8400 GS display adapter on the second computer.

I'll have to admit that I cannot make heads or tails of these results. Can you? lol

Steve

Hello Elijah.

I tried the "bad" monitor on the NVIDIA GeForce 8400 GS card for several days, and it works just fine. Interestingly, the "good" monitor that I left on the OptiPlex 780 has now ALSO started to blink and go black. There's some kind of 'degradation' effect going on with OptiPlex 780.

I am using a DVI port on the OptiPlex 780, and a VGA port on the other 'test' computer. I am using different cables on the two computers ... but only because the ports are different.

I think I have a port or cable issue of some kind. What do you think I should try next?

Thanks.

Elijah,

I need to make a modification to my previous post.

The port I'm using on my S199WFP monitor is a DVI port. However, I'm connecting the monitor to a "Dell DisplayPort" (whatever that is) on my OptiPlex. I'm using a DP2DVI cable connector (made by Molex) to do it. Is this information relevant? Should I be looking for a single cable that goes from a DVI port to a "Dell DisplayPort"? Or is it possible that my Dell monitor simply doesn't support the Dell DisplayPort?

Thanks.

Near the base of the OptiPlex 780 (on the back), there are two DisplayPorts. I presume there is a card of some sort that's been added to the computer. On each monitor, I attach a DVI cable. Then, I attach a (smaller) DP2DVI cable connector. Then I plug each cable into a DisplayPort.

Steve

Elijah,

Maybe my next step should be to open the OptiPlex and see what "card" I have that is giving me two DispayPorts. Should I just use a DVI splitter cable on one DVI port? Or will I lose some sort of functionality if I do that?

Elijah,

Excellent call-out my man. The DisplayPort (as well as a female DVI port) were covered by a plastic cover, so I had not seen them. I plugged a monitor into the DisplayPort and received the following message:

This computer has both a display port monitor and attached and a card installed in PCI-Express slot 1. This configuration is not supported. Please remove the PCI-Express card or disconnect the display port monitor.

I disconnected the DisplayPort monitor and connected a monitor to the female DVI port. That didn't work either. I received the following error message:

This computer has an add-in graphics card, but the monitor cable is plugged into the integrated video connector.

My add-in graphics card is an ATI Radeon HD 3400 Series display adapter with two (2) DisplayPorts. Presumably, it is mounted in my PCI-Express slot 1.

In a way, I'm back to where I started. Perhaps my best bet is to buy a low profile display adapter with two female DVI ports (if one exists). That way, I (a) dump the DP2DVI cable connector cables and (b) replace a display adapter with potentially bad display ports.

How does this look?:

http://www.amazon.com/EN210-SILENT-DI-1GD3-V2/dp/B004I8W4VI/ref=lh_ni_t

How do I do THAT? I don't even know what a power rating is! lol