Monitor Insomnia

We use KVM (Keyboard Video Mouse) switches at work quite a bit. A KVM allows you to have one monitor, keyboard and mouse hook to several computers. It saves space. Most of the computers in the lab are accessed remotely 95% of the time. You only have to sit down at them when something is wrong or needs to be physically changed.

We use some 8 port KVMs that are pretty basic. They are PS/2 serial switches with analog VGA monitor connections. This is typical of a couple years ago. All our new boxes do not have PS/2 ports so we are going to have to upgrade to all USB KVM in the future.

In our of the labs we had this symptom that drove most of us nuts. The monitor hooked to several boxes would not go to sleep. It would get a bunch of wavy lines. It looked like TV that was stuck between channels or just out of range of the station. I'd only given a little bit of passing attention to it in the past. This week, I finally got fed up and sat down to do some experimentation.

• Hooked a different monitor to the same KVM.
• Hooked the old monitor straight to a machine.
• Hooked an unrelated monitor to the same KVM.
• Hooked the old monitor to another KVM of the same type.
• Swapped the KVM for another of the same type.
  

These steps all required leaving the monitor to sit until it drifts off to electronic la-la-land. I don't want to hurry the process because that might taint the results.

My conclusion is the monitor is not syncing properly when it should switch to "sleep mode". Instead, it tries to sync the resolution and refresh rate automatically. This cause the monitor to throw its personified hand in the air and just leave a bunch of garbage sliding up the screen in a cranky tantrum. Thus, driving all the people up the wall who walk by the lab's windows on every trip to the restroom.

I have no idea if it is a crossed wire, power, short, corrosion, signal interception or what happens inside that KVM. It can't be that complex. Maybe there is a signal booster that takes the nap that the monitor has earned. The solution is even easier. Replace the KVM. Easer diagnosed than implemented. Swapped it out and bingo ... still does the same thing. Drat!