View Full Version : Graphics card doesn't recognize KVM Switch video signal.

April 8th, 2018, 04:50 AM
Hi everyone, I'm new here. :)
I have a problem with my KVM Switch that I use for my Windows 98 rig and my modern PC.
On the '98 pc, I can see the BIOS, POST messages and the booting of 98.
While in my modern pc I don't see a thing (monitor stays black) until the Windows log-on screen.

The monitor is a CRT, and I'm using VGA.

The graphics cards are:
NVidia GT 710 1GB PCI-e. With the ports for VGA, HDMI and DVI. Modern PC.
ATI Radeon 9250 128MB AGP. With the ports for VGA and S-VIdeo. For my 98 rig.

On my modern PC BIOS setting for video is: PCIe -> PCI -> IGP
While in my 98 rig is AGP

I tried swapping the cables, no luck.
I tried using a LCD instead of a CRT monitor, no luck.

Does anybody know how to fix it?

Oh and the KVM Switch is something like this:

April 8th, 2018, 09:36 AM
Does your modern PC have a graphical BIOS "splash screen"? You may need to disable that (sometimes called "quiet boot").

April 8th, 2018, 09:45 AM
Yes, it's disabled.
The weird thing is why the monitor doesn't display anything (even entering the BIOS or Windows dual boot OS selector) but it starts displaying in the log-on screen.

April 9th, 2018, 03:11 PM
I had a KVM switch that used power from the PS/2 plugs and the VGA output as a ground. Are both the PS/2 ports plugged in?

If it's a new(er) operating system on your modern rig, the software could only be powering the devices (PS/2 ports) when the OS is fully loaded in. I've had keyboards and mice only recognize when the OS is fully loaded in. Even when they're PS/2.

Have you used the same monitor with just your modern rig, with no KVM and get a boot screen?