Pressing start button did not work.

[Lemon law]

This happened on my wife's computer. She powered on the surge strip, pressed the start button on the computer, as long as the button was kept pressed, the fans came on, but as soon as the button was released, everything powered off. Meanwhile keeping the start button depressed did not cause the computer to boot.

She kept pressing the start button and after perhaps 10 tries, the computer powered on normally and booted up correctly and runs normally. At this point she will keep the computer powered on but sooner or later she will shut down. And then I will find out if this is just a one time thing or a regular problem.

But what is the likely cause?

 

[MisterDonut]

sometimes after replugging in your computer, the first power up will power down then resume operation (TBH, I actually don't know the details to why...I just know it happens haha)

 

[RadiclDreamer]

Sounds like either the switch is shorted, or more likely the power supply is on its way out

 

[RadiclDreamer]

sometimes after replugging in your computer, the first power up will power down then resume operation (TBH, I actually don't know the details to why...I just know it happens haha)

Thats not normal, it is normal for the fans to briefly spin up when plugging the power but thats it

 

[MisterDonut]

Ahh my mistake. Swap out the PSU and test ?

 

[gsaldivar]

Swap out PSU. If problem persists, swap the computer to a new case (switch might be bad).

Also, using a bright light, inspect the capacitors on the motherboard for any signs of pressure or leakage:

http://www.badcaps.net/images/caps/kt7/kt1.html
http://www.badcaps.net/images/caps/kt7/kt3.html

Good luck!

 

[pcgeek11]

sometimes after replugging in your computer, the first power up will power down then resume operation (TBH, I actually don't know the details to why...I just know it happens haha)

Wow!

 

[RadiclDreamer]

Swap out PSU. If problem persists, swap the computer to a new case (switch might be bad).

Also, using a bright light, inspect the capacitors on the motherboard for any signs of pressure or leakage:

http://www.badcaps.net/images/caps/kt7/kt1.html
http://www.badcaps.net/images/caps/kt7/kt3.html

Good luck!

No need to move to a new case, you can find the cable currently connected to your power switch and take a small screwdriver and short the two pins for a moment, this signals the power supply to kick into full gear (normally idling at 5v i do believe)

If this fixes the problem you can just head to your local radio shack etc and buy a momentary connect switch or examine the switch and see why it isnt working, but id bet more like a power supply failing since one of the biggest load times is at boot when it is powering the drives up.

 

[Lemon law]

Thanks to all who have replied. But it looks like I have had a diagnosis handed to me as I test further.

If I power on the computer and immediately and then hit the power button, the computer fails to boot. If I wait a few minutes after apply power before hitting the power button, the computer immediately boots. So I am assuming its now takes a few minutes for the power supply to warm up and be able to deliver adequate power.

Once the computer boots up, I can get voltage readings from sensors or directly check it with a VOM. And then checking shows its a hair south of full power but still above the
+- 5% specs that its always been.

 

[RadiclDreamer]

Thanks to all who have replied. But it looks like I have had a diagnosis handed to me as I test further.

If I power on the computer and immediately and then hit the power button, the computer fails to boot. If I wait a few minutes after apply power before hitting the power button, the computer immediately boots. So I am assuming its now takes a few minutes for the power supply to warm up and be able to deliver adequate power.

Once the computer boots up, I can get voltage readings from sensors or directly check it with a VOM. And then checking shows its a hair south of full power but still above the
+- 5% specs that its always been.

That isnt normal, the power supply is failing

 

[MisterDonut]

Wow!

Haha, I forgot that only fans power on :sneaky:. For some reason, I didn't read the post too clearly =/...MY BAD :twisted:

 

[westom]

Once the computer boots up, I can get voltage readings from sensors or directly check it with a VOM. And then checking shows its a hair south of full power but still above the +- 5% specs that its always been.

That 5% spec is where to start. To calculate what a multimeter must measure. BTW, a VOM (analog) meter is insufficient. You must measure with a 3.5 digit multimeter for sufficient accuracy. Three digits are necessary.

You numbers must exceed 3.23, 4.87, or 11.7 for any one purple, red, orange, and yellow wire when the machine has maximum load. When the system is accessing (multitasking to) all peripherals simultaneously. (Always above 4.87v for the purple wire.)

More important in your case are voltages for the green and gray wires. Green should be well above 2.0 volts when not powered. And immediately drop to well less than 0.7 volts when the power switch is pressed. Gray should be near zero. Then rise within two seconds to well above 2.4 volts when the power switch is pressed.

Problem could be the supply, a power supply controller, or a few other components of the power supply 'system'. Those numbers can identify a failure AND may tell others (with better knowledge) additinal facts. IOW, post the numbers regardless of what you think to learn more and to learn why all those numbers are important.