Fluorescent light wakes computer

  • Thread starter Thread starter Weltanscha
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Weltanscha

I have a desktop fluorescent light next to my computer,
and I noticed that, much of the time, turning the light
on will wake the computer from sleep. I'm using Windows
Vista now, and can't remember this happening with XP.
(Although I may simply not have noticed back then.)

After experimenting with moving the light around, I
determined that it is proximity of the light to the
computer case that causes it: if the light is in front
of the fan intake holes when I turn it on, this effect
happens 100% of the time. The plug end of the light cord
has a transformer/ballast attached -- moving that end around
has no effect at all.

I used a really cheap motherboard, (ECS 865-PE A), so I'm
assuming the problem lies there and not on some other
component. I ran a hardware-checking program while turning
the light on and off, and no problems were reported. Still,
I'm worried that whatever is causing the wakeup effect
might cause other problems--now, intermittently, or in the
future.

(For example, the first time I installed Office
Standard, Help would always pull up the results in the
form of an XML document. Problem
went away, inexplicably, with a reinstall. Weird stuff
happens, periodically, with computers, but now I'm wondering
whether to blame any/everything that goes wrong on this light thing!)

Any thoughts on what, if anything, to do?

- Tom
 
Weltanscha said:
I have a desktop fluorescent light next to my computer,
and I noticed that, much of the time, turning the light
on will wake the computer from sleep. I'm using Windows
Vista now, and can't remember this happening with XP.
(Although I may simply not have noticed back then.)

After experimenting with moving the light around, I
determined that it is proximity of the light to the
computer case that causes it: if the light is in front
of the fan intake holes when I turn it on, this effect
happens 100% of the time. The plug end of the light cord
has a transformer/ballast attached -- moving that end around
has no effect at all.

I used a really cheap motherboard, (ECS 865-PE A), so I'm
assuming the problem lies there and not on some other
component. I ran a hardware-checking program while turning
the light on and off, and no problems were reported. Still,
I'm worried that whatever is causing the wakeup effect
might cause other problems--now, intermittently, or in the
future.

(For example, the first time I installed Office
Standard, Help would always pull up the results in the
form of an XML document. Problem
went away, inexplicably, with a reinstall. Weird stuff
happens, periodically, with computers, but now I'm wondering
whether to blame any/everything that goes wrong on this light thing!)

Any thoughts on what, if anything, to do?

- Tom
Click to expand...
Get another desk light!!!
 
Weltanscha said:
I have a desktop fluorescent light next to my computer,
and I noticed that, much of the time, turning the light
on will wake the computer from sleep. I'm using Windows
Vista now, and can't remember this happening with XP.
(Although I may simply not have noticed back then.)

After experimenting with moving the light around, I
determined that it is proximity of the light to the
computer case that causes it: if the light is in front
of the fan intake holes when I turn it on, this effect
happens 100% of the time. The plug end of the light cord
has a transformer/ballast attached -- moving that end around
has no effect at all.

I used a really cheap motherboard, (ECS 865-PE A), so I'm
assuming the problem lies there and not on some other
component. I ran a hardware-checking program while turning
the light on and off, and no problems were reported. Still,
I'm worried that whatever is causing the wakeup effect
might cause other problems--now, intermittently, or in the
future.

(For example, the first time I installed Office
Standard, Help would always pull up the results in the
form of an XML document. Problem
went away, inexplicably, with a reinstall. Weird stuff
happens, periodically, with computers, but now I'm wondering
whether to blame any/everything that goes wrong on this light thing!)

Any thoughts on what, if anything, to do?

- Tom
Click to expand...

The reset and power switch cables inside the computer, function
as antennas. The transient from switching of the light is
getting coupled into the wire. To reduce the coupling, try
moving the lamp away from the computer.

Paul
 
In alt.comp.hardware.pc-homebuilt Paul said:
The reset and power switch cables inside the computer, function
as antennas. The transient from switching of the light is
getting coupled into the wire. To reduce the coupling, try
moving the lamp away from the computer.

Paul
Click to expand...

I think there's a common input on some motherboards for "infrared" or
something similar, used to wake up a computer. It's usually
unterminated if not used. If so, terminating the connection with a
medium-to-high value resistor might stop the wake-up-call.

As an alternative:
Look through the BIOS settings for "wake up on"; and disable things that
you don't want or use. (Keyboard input is a common one. You're
probably looking for something else.)
 
Weltanscha said:
I have a desktop fluorescent light next to my computer,
and I noticed that, much of the time, turning the light
on will wake the computer from sleep. I'm using Windows
Vista now, and can't remember this happening with XP.
(Although I may simply not have noticed back then.)
- Tom
Click to expand...

If your mobo/soundcard/etc has an IR receiver that you do not use, cover it
with a piece of tape.
 
I have a desktop fluorescent light next to my computer,
and I noticed that, much of the time, turning the light
on will wake the computer from sleep. I'm using Windows
Vista now, and can't remember this happening with XP.
(Although I may simply not have noticed back then.)

After experimenting with moving the light around, I
determined that it is proximity of the light to the
computer case that causes it: if the light is in front
of the fan intake holes when I turn it on, this effect
happens 100% of the time. The plug end of the light cord
has a transformer/ballast attached -- moving that end around
has no effect at all.

I used a really cheap motherboard, (ECS 865-PE A), so I'm
assuming the problem lies there and not on some other
component. I ran a hardware-checking program while turning
the light on and off, and no problems were reported. Still,
I'm worried that whatever is causing the wakeup effect
might cause other problems--now, intermittently, or in the
future.

(For example, the first time I installed Office
Standard, Help would always pull up the results in the
form of an XML document. Problem
went away, inexplicably, with a reinstall. Weird stuff
happens, periodically, with computers, but now I'm wondering
whether to blame any/everything that goes wrong on this light thing!)

Any thoughts on what, if anything, to do?

- Tom
Click to expand...

I'm the original poster.

Thanks for all the good sugestions. In the end, however, it turned
out to be
the mouse, which is right by the computer case. I had put the
(optical) mouse out of my mind as a candidate, since I was used to
getting annoyed by it's "waking up" the displays when bumped, but knew
that the red light beneath went out when the computer proper went to
sleep, and thus was "blind" to bumps. Thus I didn't really consider
the possibility that it could wake up the computer. So I forgot about
the mouse buttons, and when I disabled pointing devices for computer
wakeup, problem went away.

Thanks again.

- Tom
 
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