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Computer Turns On all by Itself


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#1 Torvald

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Posted 11 July 2010 - 08:25 PM

My sister-in-law called me about a month ago and reported that during a big thunderstorm, her Windows XP computer powered on all by itself and started up Windows. Her computer was fortunately protected by a surge suppressor, so I told her not to worry, thinking it was a one-time electrical glitch caused by lightning.

However, she just called again tonight and reported that her computer had been intermittently turning itself on all by itself since last month, gradually getting worse over time, and that today it had actually turned itself on nine (9) separate times. She also said it appears to be turning on only during daylight hours, so at least it's not interrupting her sleep at night.

Due to my work schedule, I won't be able to go over and physically check out her computer until this weekend, so I wanted to post this message in the meantime to gather advice. I've experienced problem computers that would randomly turn themselves off, but have never before seen one that randomly turned itself on. Won't know if this is being caused by malicious software until I get a chance to examine her computer, so am posting first in this forum just in case this is a Windows XP problem, or even a hardware problem possibly caused by the thunderstorm a month ago.

Has anyone else experienced this kind of situation? If so, what did you do to help fix the problem? Any and all advice is appreciated.

EDIT: Moved from XP to Internal Hardware ~ Hamluis.

Edited by hamluis, 13 July 2010 - 12:28 PM.

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#2 MrBruce1959

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Posted 11 July 2010 - 08:40 PM

Is the house haunted? Just kidding.

Can you please post some information on this computer such as make and model number?

Kind regards.
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#3 westom

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Posted 12 July 2010 - 09:04 AM

My sister-in-law called me about a month ago and reported that during a big thunderstorm, her Windows XP computer powered on all by itself and started up Windows. Her computer was fortunately protected by a surge suppressor, so I told her not to worry, thinking it was a one-time electrical.

A computer is powered off and on by the power supply controller. This circuit has numerous inputs. A most common reason for this event is the Power On Event inputs. For example, the modem can ask the power supply controller to power on the machine when the phone rings.

These power on requests are enabled in the BIOS. Simply go into the BIOS to disable each function.

For example, pressing a keyboard space bar can power on the machine if that function is enabled in the BIOS.

If the device does not exist, but is enabled by the BIOS, then the wire is an antenna. Radiated noise might be interpreted as a request to power on the computer. Power supply controller then starts a boot.

#4 Torvald

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Posted 12 July 2010 - 08:36 PM

Mr Bruce,

My sister-in-Law's computer is a home built model consisting of basically the following:

MSI KT3 Ultra Motherboard
AMD Athlon XP 1.3 GHz CPU
1 GB of DDR SDRAM 184-pin RAM
Nvidia GeForce 6200LE Videocard
80GB Harddrive
DVD-ROM/CD-RW
PCI Network card

****** A little more info about the mysterious self-start problem was obtained today: Her computer and her television are both connected to the same cable TV outlet via a split "T" connector. Also, the computer self-starts only happen while she's watching TV. She said when the computer self starts, the TV makes a popping sound and goes blank for a moment.

Is it possible that some sort of Windows XP Home setting is telling the computer to power on when it receives a LAN signal? If so, the TV might be causing some unintended interference. Any ideas on what I might look for and/or try when I go over this weekend to trouble shoot her computer, other than checking the BIOS settings

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#5 westom

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Posted 12 July 2010 - 08:45 PM

Any ideas on what I might look for and/or try when I go over this weekend to trouble shoot her computer, other than checking the BIOS settings

Measure voltages on inputs to the power controler with a multimeter. Wires that connect a power supply to motherboard are the purple, green, and gray wires. The power contoller is being asked (or told) to power on. View (measure) those (and other) inputs.

#6 MrBruce1959

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Posted 12 July 2010 - 08:59 PM

If you wish to try what westom has suggested, what I am posting below should help you.
I have seen westom post here before, he seems to know quite a bit about computer power issues from what I've seen of his posts in this forum.

The purpose of this procedure is to bypass the motherboard to test a ATX PSU. Some manufacturers Like Dell have used some non ATX PSUs which have a different pinout for the 20/4 pin connector, please confirm that your PSU is a ATX type before using this procedure.

Caution:
This procedure will involve working with live 12VDC electrical potentials which if handled improperly may lead to electrical shock. Proper precautions should also be taken to prevent electrostatic discharges (ESDs) within the case of the computer. For safety purposes please follow the instructions step by step.

First, shutdown your computer. Then unplug the power cable going into your computer.

Once you have opened the case, touch the metal of the case to discharge any static electricity.

The connector of the PSU which connects to the motherboard is readily recognizable by the number of wires in the bundle. To disconnect it you will need to press on the plastic clip to disengage it and then pull the connector up and away from the motherboard. Please take notice of the location of the locking tab and the notch on the socket of the motherboard, this will only connect one way as it is keyed. This wire bundle will have a memory of the way it has been installed and will want to bend back that direction, you may have to play around with it to find a position that the connector will stay in the same position while you run the test.

Posted Image
www.playtool.com

From the top left to right the pins are 13-24, the bottom from left to right are 1-12.


Please notice that there are PSUs with 24 pin and 20 pin connectors, the location of the green wire in the 24 pin connector is #16, and the green wire in the 20 pin connector is #14. If you look at the connector with socket side facing you and the clip on the top the number one pin will be on the bottom left corner. This makes the pin out for the 24 pin connector from left to right 13-24 on top, and 1-12 on the bottom. The pin out for the 20 pin connector from left to right is 11-20 on top , and 1-10 on the bottom. If you look at the connectors you notice that these are sockets that fit over the pins on the motherboard where the PSU cable attaches, this is where you will place the jumper. For a jumper you will need a piece of solid wire about the size of a paper clip (20-22 awg), preferably a wire with insulation. It will need to be large enough to fit firmly into the socket so that it will not need to be held in place while testing. You are at risk of electrical shock if you are holding the jumper when you power up the PSU. Insert one end of the jumper into the socket of the Green wire, and insert the other end into the socket of any Black wire.

Once the jumper is in place plug the cord back in. If the PSU is working properly the case fans, optical drives, hdds, and LEDs should power up and remain on. I would suggest that you not leave this connected any longer than is necessary for safety purposes.

To reconnect the 20/4 pin connector unplug the power cord, remove the jumper, and reconnect the connector. Take a moment at this time to make sure that nothing has been dislodged inside the case.


You may either have a setting in your BIOS power setup menu turned on. The setting could be related to your LAN (PCI Network Card) powering on the system.
This feature was used in the old days of BBS bulletin boards where a system was set up to turn its self on if a pulse was present on the line. This feature was also controlled by a MODEM in the old days of dial up connections, now a network card (LAN) can do the same thing.

Bruce.
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#7 Torvald

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Posted 20 July 2010 - 10:31 AM

Good news!

Was able to check out my sister-in-law's computer and have discovered the weird source of the problem.

Her televison was using a 3-way t-connector to share a cable connection to the internet along with her Windows XP computer. Apparently, the TV was somehow damaged by linghtning a few weeks ago during a thunder storm and is intemittently shorting out. When it does so, it emits a terribly lound carracking sound, goes blank for a few seconds, and then resumes. At the same time, her computer suddenly powers itself on. I would never have believed it if I hadn't seen it happen several times myself this past weekend.

Well, I was able to stop her computer from self powering on by going into the the BIOS and changing some of the power management settings related to waking up the computer. We will now also quickly go buy her a replacement telvision, since hers is about to die and is probably also an electrical/fire hazard.

Thanks for all the advice given, especially the tip about changing BIOS settings.

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#8 westom

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Posted 20 July 2010 - 10:54 AM

Apparently, the TV was somehow damaged by lightning a few weeks ago during a thunder storm and is intermittently shorting out.

Solution is not complete yet. Informed homeowners earth every incoming wire to single point ground. Every wire connected directly (ie cable) or via a 'whole house' protector (AC electric, telephone). Either a surge is harmlessly absorbed outside the building (single point ground). Or it is inside hunting for earth destructively via appliances - ie that TV.

She had energy inside the building. That means she does not have the always required single point earth ground. Or some incoming utility does not make the short (ie 'less than 10 foot') connection to that ground either directly or via a 'whole house' protector.

If the surge is permitted inside next time, what appliance will it hunt for earth via? Don't forget to solve the original problem - ie AC electric surge hunted for earth ground this time via the TV.

Very interesting problem. Thanks for providing a so curious and new story.

#9 Torvald

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Posted 01 August 2010 - 09:52 AM

Solved the problem.

Her TV was progressively going bad and it finally shorted out completely.

We bought her a new High Definition LCD TV (much better than her old tube TV); She now has a much better television, and there are no longer any power spikes causing her computer to turn on.

Hooray.

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