# Can I connect a monitor while my computer is on?



## samn122 (Jul 28, 2009)

I'm setting up a second display but I'm not sure if I can connect it to my computer while its still on. Its troublesome to turn off the computer and connect the monitor then turn it back on so I'm thinking of connecting it while its still on. Would it be ok to connect it while the computer is in sleep mode?


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## adrianr2z (Mar 28, 2011)

Yes of course it you could! I have done it many times and just did it recently to test out a monitor. Don't worry, nothing will happen.


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## win2kpro (Jul 19, 2005)

Nothing, other than "hot swappable" devices should be plugged into a powered on machine.

http://www.computerhope.com/issues/ch001059.htm


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## DoubleHelix (Dec 10, 2004)

There's nothing wrong with connecting a monitor while a computer is on. I do it every morning when I connect my laptop to an external monitor.


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## win2kpro (Jul 19, 2005)

Although on occassion I have done it myself, I have to disagree with the statements regarding "hot swapping" monitors. VGA and DVI circuits are not designated as hot swappable.

All connector and sockets have a life referred to as "cycles" (plugging and unplugging). At one time I looked up the number of cycles for Molex VGA connectors and if I recall correctly the manufacturer (Molex) specs for VGA connector sockets was 100 "cycles". This doesn't mean that the socket will fail at exactly 101 "cycles", but at some point the pins on the connector or the female connectors in the socket will fail from use. "Cycles" is just a figure calculated by the manufacturer similar to MTBF for motherboards based on testing. Since many manufacturers use components of lower quality than Molex, therefore the life "cycles" will likely be less than Molex products.

I just happened to have a PDF user guide that I downloaded recently for a ViewSonic VA2702W LCD display. On page 6 of the Quick Start Guide for this display is the following information.

*Quick Installation

1. Connect power cord (and AC/DC 
adapter if required)

2. Connect video cable*

• Make sure both the LCD display and 
computer are turned OFF

Then there is some information regarding connecting to a Mac that I won't bother to copy. The instructions then continue;

*3. Turn ON LCD display and computer*

Turn ON the LCD display, then turn ON 
the computer. This sequence (LCD display
before computer) is important.

The Quick Start Guide then goes on about receiving a Windows message, blah, blah, blah.

I don't know why ViewSonic who builds millions of monitors would consider the sequence important unless they don't want a purchaser to make a mistake and have the computer on before plugging in the monitor.

Individual can do whatever they please, but I personally am not going to "hot plug" a monitor and recommend that others "hot plug" non "hot swappable" devices.


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