Computer is in power off state but is actually in power on state \ VOGONS

Computer is in power off state but is actually in power on state

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First post, by Stojke

Posted on 2016-10-07, 15:18

Stojke Offline

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Has any one ever had this problem where the computer shuts down, turns off all devices and puts it self into power off state but it can not be turned on again by button press?
When the computer is shut down it can only be turned on by unplugging the power supply from the mains voltage and plugging it back in. Only then will the computer normally turn on and shut down again. But the cycle has to repeat again as it is the only way to turn the computer ON again after turning it OFF.

This lead me to believe that the computer, even though in power off state, is still some how in power ON state. 1 out of 5 completely functional power supplies seems to overcome this issue and turns ON the computer after it has been turned OFF normally, but keep in mind that this power supply can turn on computers that have serious short circuit problems in them (for example an burnt graphics card chip that continues to burn and smoke on this psu, but shuts down, or does not power up at all, on other power supplies).

Is this caused by some passive component/s on the motherboard? I have updated and downgraded the bios a couple of times and have tried different micro processors, memory configurations, graphics cards and peripherals.

Any help would be appreciated 😀 (best wishes too all as I've not been active much)
[EDIT] Motherboard is an Asus M2NPV-VM [EDIT]

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Reply 1 of 8, by Jorpho

Posted on 2016-10-07, 15:34

Jorpho Offline

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Maybe your power switch is just faulty?

If you're determined to get to the bottom of this, I would suggest unplugging the power switch completely, and manually shorting the appropriate pins to turn the computer on and off.

Reply 2 of 8, by Aideka

Posted on 2016-10-07, 15:42

Aideka Offline

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I have seen this behavior in a few cases of bad PSU caps, and also bad MB caps. I know you said the PSU:s are functional, but I would check just to be sure.

EDIT: Come to think of it, this could just be a problem with another NForce chipset cooking itself to death.

Reply 3 of 8, by Stojke

Posted on 2016-10-07, 16:07

Stojke Offline

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Kudos for quick replies guys. I have already tried a few different power switches and manual pin shorting, but the result is still the same. All five power supplies were thoroughly tested with different computers pulling more or less power than the next. The motherboard caps looks pretty decent, no bulging, but I know they don't have to look bad to be in that state. I have decided, upon recommendation, to follow the psu start lines (green, ground) and replace all the caps along those lines.

The chipsets are cool as ice.

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Reply 4 of 8, by Aideka

Posted on 2016-10-07, 16:09

Aideka Offline

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Stojke wrote:
Kudos for quick replies guys. I have already tried a few different power switches and manual pin shorting, but the result is still the same. All five power supplies were thoroughly tested with different computers pulling more or less power than the next. The motherboard caps looks pretty decent, no bulging, but I know they don't have to look bad to be in that state. I have decided, upon recommendation, to follow the psu start lines (green, ground) and replace all the caps along those lines.

The chipsets are cool as ice.

The chipsets may kill theirselves without even getting too hot, they are from around the ROHS starting periord, and many Nvidia chips from then just don't work anymore.

Reply 5 of 8, by Stojke

Posted on 2016-10-07, 16:16

Stojke Offline

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The computer works flawlessly while powered on, the only problem is that it does not want to power on after being shut down (the only exception is the super flower psu that powers it on even than).

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Reply 6 of 8, by Jepael

Posted on 2016-10-07, 18:27

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Stojke wrote:
The computer works flawlessly while powered on, the only problem is that it does not want to power on after being shut down (the only exception is the super flower psu that powers it on even than).

Remove bios battery and try again. Change to new battery. Sometimes funny things happen when they are almost empty.

Reply 7 of 8, by Stojke

Posted on 2016-10-07, 19:08

Stojke Offline

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Did that as well, various bios settings and combinations were tried. Its pretty much the starter circuit faulty at this point. But I can not find any information of how an computer motherboard starter circuit would look like or function like. I do guess it is transistor switch driven, but I am not sure how (or how is it layed out and connected to the chipset).

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Reply 8 of 8, by yawetaG

Posted on 2016-10-08, 08:49

yawetaG Offline

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Stojke wrote:
The computer works flawlessly while powered on, the only problem is that it does not want to power on after being shut down (the only exception is the super flower psu that powers it on even than).

Had a eMac that did that, when it ultimately failed and I took it apart it turned out almost all caps in the power supply had spilled their white gooey insides over the print 😵 ...powering on makes a machine shortly put a heavy load on a lot of components at once, and if caps are failing that will become apparent in such a moment.

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