Power button died?

by schatzieny Dec 20, 2004 11:27PM PST

I was about to do some troubleshooting on my mom's PC -- Emachine T1140, XP Home. She'd been having some virus and spyware issues. The box hasn't been touched for approximately 2 months. It's plugged into a surge protector.

Monitor switches on OK (plugged into same surge protector). PC will not start up at all. Tried a different outlet, different power cord, holding the button in for a few seconds, etc.; nada.

What could have happened? Any ideas/help are appreciated.

Discussion is locked

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First, not being wise, but

by Ray Harinec Dec 21, 2004 4:31AM PST

is the switch on the rear of the power supply in the ON [1] position?? Is the 115/220 switch set properly? These things can happen with a computer sitting unused as people move them.

Next step is to take the cover off the tower and check all of the wiring and clean all fans. [cleaning the fans at this time won't make it start, but if the power supply has failed it might show why].

To test the switch, find the two terminals on the mobo where the switch is plugged in and momentarily short them together with the blade of a small slot screwdriver.

When the PS is plugged into a hot AC line and the switch on the rear is on, there should be 5 volt logic power always applied to the mobo. Many mobo's have an LED on the mobo that is lighted when that 5 volts is there. Do you see anything like that?

Do you have a voltmeter? Know how to use it?? can steer you more if you have and can.

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Power switch

by schatzieny Dec 21, 2004 11:43PM PST

Thanks for the reply.

Yes, I did check the power supply switch, it was on in the 115 position.

I haven't gotten around to opening the box yet. Will probably be doing that this weekend. I'll look for the things you've mentioned.

I don't have a voltmeter, just a simple circuit tester. Don't know if that's enough for what you're thinking of.

I will let you know what I find after I get into the box.

Thanks again.

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We'll be watching for your input.

by Ray Harinec Dec 21, 2004 11:52PM PST

Not exactly sure what a circuit tester is, unless you mean something to check the AC power outlets. That'll be of no real use.

Can troubleshoot without a voltmeter, so no loss.

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No progress so far

by schatzieny Dec 26, 2004 11:36PM PST

Okay -- followed your suggestions: opened the box, all the wiring looks good, very clean inside but blew out any dust that might have been there.

Found what appear to be the terminals for the power switch (one labeled "power switch," one labeled "power LED") but could not figure out how to short them since they just seemed to be some kind of thin plastic. (I assume I was supposed to be doing this with the power cord plugged in, correct?) Made sure they were plugged in tightly.

I didn't see any LED's lit up on the mobo while the power was plugged in.

Finally, yes a circuit tester only shows if juice is flowing.

What's next?

And hope you had a happy holiday.

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The Power switch and the power LED

by Ray Harinec Dec 27, 2004 10:07AM PST

are different items. Each should have two wires/contacts to connect to the mobo. The polarity of the the wires is important for the LED but not for the Power switch. Don't short the LED pins.

The little black plastic clips are the connectors. You can raise them or lift them off and short the two pins attatched to the mobo with the tip of a scewdriver MOMENTARILY only. That's all that the switch does when you hit it.

If, perchance, you have the power switch leads and Power LED leads discombobulated, you may have found your problem. LOL

Had a great holiday, thanx.

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Remember the idea for shorting the pins

by Ray Harinec Dec 27, 2004 10:16AM PST

was simply a troubleshooting step to eliminate the switch as a possible cause. Good chance that the power supply went bad. replacements are cheap, just get one with a little higher wattage rating [50 watts or so]than the one that is in there.

I have been assuming that the system had been working well and then failed and that no HUMAN being had been inside the computer before you found the need to troubleshoot. Again 30 plus years of troubleshooting gives 95 % confidence that if a human was in the machine before that, the problem will be found in the vicinity of where the human had been.

When people make the first post, they don't always tell the complete pre history of the problem.

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won't power up

by jcrobso Dec 27, 2004 1:40AM PST

I have just finsihed reading all your steps so far.
Emachine PC's are known for having weak power supplies, so there is a very good chance that it's the power supply. For ATX MB the powersupply has a standby voltage that is allwise on, this feeds the MB for the turn on, the MB feeds the power button, when pressed the MB tells the powersupply to turn on. So you could have a bad MB or a bad Power switch also. If your VERY CAREFULL you can trace the wire from the power button to where it plugs into the MB and CAREFULLY short the 2 pins together for 1 second if it powers up the the switch is bad, replace the switch. If the PC was in my shop the first thing I would do after cleaning would be to try a different PS, then try shorting out the powerswitch pins. You may have some component like a memory stick go bad but the odds are on the PS, if this dosen't get the PC to power up them it's MB time or a new PC. John

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Shorting powerswitch pins

by schatzieny Dec 27, 2004 6:13AM PST

I'm still not clear on exactly how to do that. I'm pretty sure I found them, but I tried with the screwdriver technique recommended by Ray and nothing happened. Either I didn't do it correctly or it's dead.

Someone else mentioned the power supply as well. I will work on this some more and see if I can make some headway.

Thanks.

Power button died?

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