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VGA Signal Interrupter Switch

Electron2002

Jan 9, 2013
1
Joined
Jan 9, 2013
Messages
1
At my office, I have a dual monitor setup, attached to my laptop. One of the monitors is connected through HDMI, the second through VGA. I have had a persistent issue that when the computer gets turned on or wakes up the monitors, the monitor connected through VGA displays an "Out of Range" error. The computer itself sees the monitor and is sending signal however. From testing we know that the actual issue is from within the computer, however I can't get my company's IS department do any more about the issue.

The workaround I have found for the concern, is to slightly disconnect the VGA cable from the laptop's base station, so that the monitor looses the signal momentarily, then plug it back in before the computer drops the output signal. This has the affect of causing the monitor to resync to the signal, without causing a drop in the actual signal.

This unfortunately also wears on the VGA port and cable, as I'm forced to do this several times a day.

What I am thinking about doing, is to make a switch box, that I can install within the VGA circuit, that I can quickly switch to cause the same affect as unplugging the cable. I had considered buying a simple VGA A/B switch, however these switches typical switch most if not all the individual circuits and many people complain of them causing image concerns.

My preference would be to pass through most of the circuits and only switch a select few, to reduce interference and resistance within the switch. I would also intend to use a simple momentary open switch, so that a simple touch would break the signal and reconnect it in split second.

So my ultimate question is, if you were going to built a switch for this purpose, what circuits within the VGA cable are the ones that would need to be switched to cause a monitor to drop signal and reset?

Hope this all made sense.

Thanks,
Tom
 
Last edited:

gorgon

Jun 6, 2011
603
Joined
Jun 6, 2011
Messages
603
I would try to interrupt 13(Hsync) and 14(Vsync) first. Be aware that you should be carefull not to add too much cable lenght to the existing wiring, due to the timing and impedance.
 
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