Computer Shuts off when light switch is turned on

[Anonymous user]

On the exterior of my house is a bright flood light. When turned on, my PC dies (immediately off, no shutdown performed). I do have it on a UPS (RS-1200) and plugged into a surge + power outlet. Any ideas of where to begin to troubleshoot this?

[Erasmus_apc]

I would do the following:

1) Does the PC work fine without the RS unit providing it's power (i.e. PC getting power from the outlet directly).
2) Are there any events logged on the RS unit via our PowerChute software?
3) Does the UPS even stay on during this "issue"? Or does it shut down/die instantly with the computer?
4) You said you " +do have it on a UPS (RS-1200) and plugged into a surge / power outlet.+ " Does this mean the PC is plugged into one of the Surge Protection only outlets? Or is the UPS daisy chained to a surge protector? Please describe this a little more for us.
5) Is the flood light on the same circuit as the UPS?
6) Was this configuration you have working in the past? Or has the flood light always shut off the RS unit? Have you ever had any other issues with the RS unit in the past?

[Anonymous user]

what operating system are u running?
what PSU rating is in ur computer?

I am having a similar but different issue.
When my printer starts up my computer goes to sleep, the wakes up in 15 sec.
(It did it today out of the clear blue - printer was not starting up.)

It did not do this when I was running XP and had a 350W PSU and 2GB of ram. I since added 4GB RAM and changed the PSU to a 700W unit and am running Windows 7 64bit beta. But I don't know which change started it or if it is a UPS issue. UPS does not record short drop outs. It has however recorded two with a total of 5min on UPS in the last day. I didn't see them so it may have been last night.

computer connected to a 750VA model BE750BB

I figure computer is drawing in the neighborhood of 450W. not sure. It is pretty close to a PF=1. It ran pretty good on the 350W PSU.

[Anonymous user]

Thanks for the responses
1) I see the same behavior with the computer plugged directly to a power strip. Flip the outside light on and the comp dies. I didn't mention this, but it can power up and operate fine when the light is on the only problem is when the light is off and is switched on.
2) There are no events logged in the powerchute software. However, the software does have a note on the screen that "Power problems of a very short duration are not recorded here." Is there anyway to enable more logging?
3) The UPS does stay on, as well as everything else connected (I'll describe all equipment below). I do not get any error beeps or signal lights from the UPS (other than the "On-Line" Light which remains on).
4) Configuration described below...
5) I'm not certain that the flood light is on the same circuit. I really know very little about electrical wiring. And I can't be positive this is even a power issue, all I really know is flipping on the light causes it.
6) We just recently moved into the house and it has been happening since we moved in. It seemed random at first until we figured out that it was the flood light causing it.

OS: XP SP3
Power Supply: [Raidmax Volcano 630W Model: RX-630A|http://www.raidmax.com/specs/volcano.htm]
Intel Core 2 Duo E6400 Conroe 2.13GHz LGA 775 65W Dual-Core Processor
EVGA GeForce 7950GT 512MB PCI Express Graphics card
4 7200 RPM drives in RAID0+1

The Computer, 17" LCD Monitor, Cable Modem, and a Router are plugged into the UPS (the "Surge + Power" Outlets). A second monitor (old 21" CRT) and speakers are plugged into the "Surge Only" Outlets on the UPS. The UPS is then plugged directly into a wall outlet. There is no additional surge protector or power strip involved, (sorry I wasn't clear on all this in the first post).

Powerchute selftest passed.
It shows 100% charged.
No events recorded.
Input voltage 118 volts.
Typically it shows it supplying around 190-200 watts, runs up to around 240-245 when gaming.

Settings:
"Keep my computer on as long as possible" shutdown when 5 min battery remaining.
I've tried Medium and High sensitivity.
For the voltage Settings I've tried the default, 94 volts, and all the way up at 104 volts for the setting "Your battery backup will intervene if AC utility voltage goes below:"

[Anonymous user]

I have a similar problem when my laser printer wakes up.I may be on to something.
I unplugged my computer from the UPS and plugged it into the same outlet the printer is plugged into and I don't have the problem.
Something in the UPS. Could it be batteries. The batteries in the old UPS I had were good till the circuit board died - about 5 years. These are only 4 years old.

[BillP · Accepted solution]

UPS batteries wouldnt cause an issue like this unless the UPS were trying to go to battery and the battery was bad, thus the entire UPS would turn off.

it sounds like maybe something with inrush current or maybe something with grounding - ground loop? i am not sure either to be honest but ill throw those out there.