computer isn't turning on: need help

[zach_ski]

Well couldn't figure this out on my own so I went online to find
answers.. hopefully someone can help me here.

Allright, so one day after coming back from a long day at work I go to
turn on my computer... computer doesn't turn on! So I check to see if
it's plugged in to my PSU, and in the wall... check. Check to see if
the PSU is turned "on"... check. So now I figure a few wires
were jiggled around inside so I check ALL wires inside my case,
everything is properly secured. Now I'm stuck... the "green
light" on the motherboard is on, but nothing comes on when I push
in the button on my case... is there anyway to by pass the button on
my case?? I even took off the front and actually pressed in the button
that goes to the mobo.

I'm figuring the PSU is fine since my mobo light turns on, same with
my mobo.. couldnt be a short with that.. or maybe im totally wrong?
Can that mobo light still turn on even if there is a short ?? I came
to my own conclusion that it HAS to be the case... what do you guys
think?? All the wires are plugged in... power IS getting to the mobo
since the green light near the expansion slots turn on... I cant think
of anything else.

here are the specs:
ASUS A8N-SLI Socket 939
AMD Athlon 64 3800
Antec NEOPOWER PSU 480watts
Corsair ram.. 2gigs

I appreciate it if anyone could give me some input on my current
situation.. thanks!

 

[redkcir]

Well couldn't figure this out on my own so I went online to find
answers.. hopefully someone can help me here.

Allright, so one day after coming back from a long day at work I go to
turn on my computer... computer doesn't turn on! So I check to see if
it's plugged in to my PSU, and in the wall... check. Check to see if
the PSU is turned "on"... check. So now I figure a few wires
were jiggled around inside so I check ALL wires inside my case,
everything is properly secured. Now I'm stuck... the "green
light" on the motherboard is on, but nothing comes on when I push
in the button on my case... is there anyway to by pass the button on
my case?? I even took off the front and actually pressed in the button
that goes to the mobo.

I'm figuring the PSU is fine since my mobo light turns on, same with
my mobo.. couldnt be a short with that.. or maybe im totally wrong?
Can that mobo light still turn on even if there is a short ?? I came
to my own conclusion that it HAS to be the case... what do you guys
think?? All the wires are plugged in... power IS getting to the mobo
since the green light near the expansion slots turn on... I cant think
of anything else.

here are the specs:
ASUS A8N-SLI Socket 939
AMD Athlon 64 3800
Antec NEOPOWER PSU 480watts
Corsair ram.. 2gigs

I appreciate it if anyone could give me some input on my current
situation.. thanks!

You can short out two of the pins to start up the power supply, but
that may not be the best thing to try.
This site will show you what pins what.

http://www.helpwithpcs.com/courses/power-supply-basics-inc-pinouts.htm

 

[helmut]

You can short out two of the pins to start up the power supply, but
that may not be the best thing to try.
This site will show you what pins what.

http://www.helpwithpcs.com/courses/power-supply-basics-inc-pinouts.htm

or you could put the power_on pins onto the reset pins then use the reset
button to switch on.This is safer than jamming a screwdriver in there.

 

[Rod Speed]

Well couldn't figure this out on my own so I went online
to find answers.. hopefully someone can help me here.

Allright, so one day after coming back from a long day at work
I go to turn on my computer... computer doesn't turn on! So I
check to see if it's plugged in to my PSU, and in the wall... check.
Check to see if the PSU is turned "on"... check. So now I figure
a few wires were jiggled around inside so I check ALL wires
inside my case, everything is properly secured. Now I'm stuck...
the "green light" on the motherboard is on, but nothing comes
on when I push in the button on my case... is there anyway to
by pass the button on my case??

Yes, you can connect the two pins that the switch connects
to on the motherboard with a screwdriver and see if that
turns it on. Thats one of the least likely possibilitys tho.

I even took off the front and actually pressed
in the button that goes to the mobo.

I'm figuring the PSU is fine since my mobo light turns on,

Not necessarily. All that shows is that its still producing the 5VSB voltage.

Not that it can power the system properly, or even
notice that the motherboard has told it to turn on.

same with my mobo.. couldnt be a short with that..

All that shows is that its still producing the 5VSB voltage.

There can still be a short elsewhere or it can have died and can
still be showing that its getting the 5VSB from the power supply.

or maybe im totally wrong?

Fraid so.

Can that mobo light still turn on even if there is a short ??

Yep. And there is more than just shorts involved too.

I came to my own conclusion that it HAS to be the case... what do you guys think??

I gave up thinking, it just makes my head hurt.

All the wires are plugged in... power IS getting to the mobo
since the green light near the expansion slots turn on...
I cant think of anything else.

The two main possibilitys are that the power supply has failed
and that its ignoring the command by the motherboard to turn
on when you press the button, or that the motherboard doesnt
even notice that you have pressed the button anymore.

Its obviously cheaper and easier to try another
power supply than another motherboard.

here are the specs:
ASUS A8N-SLI Socket 939
AMD Athlon 64 3800
Antec NEOPOWER PSU 480watts
Corsair ram.. 2gigs

I appreciate it if anyone could give me some input on my current situation.. thanks!

You can get useful information if you have a multimeter and know how
to use it. But if you havent, the first thing to try a new power supply.

If that makes no difference, check for bad caps on the motherboard.
These are the usually blue or black plastic covered post like things
that stick up vertically from the motherboard surface. The tops
should be flat. If any have bulged or have leaked, thats a bad
cap and likely the reason that the system isnt starting anymore.

If there arent any bad caps visible, try unplugging all the cards, even
the video card. One of those can fail and stop the system starting.
Worth unplugging the drives too, they dont often produce that effect,
but it can happen.

If it looks like a dead motherboard, Asus has a 3 year warranty
and it would be worth trying the motherboard loose on the desktop
just before you return it. You can get a short to case if someone
has dropped a screw into the system and hasnt got it out and
loose on the desktop is the best way to check for a short like that.
Pain to try, but worth it when you have eliminated other possibilitys.

 

[redkcir]

Yes, you can connect the two pins that the switch connects
to on the motherboard with a screwdriver and see if that
turns it on. Thats one of the least likely possibilitys tho.


Not necessarily. All that shows is that its still producing the 5VSB voltage.

Not that it can power the system properly, or even
notice that the motherboard has told it to turn on.


All that shows is that its still producing the 5VSB voltage.

There can still be a short elsewhere or it can have died and can
still be showing that its getting the 5VSB from the power supply.


Fraid so.


Yep. And there is more than just shorts involved too.


I gave up thinking, it just makes my head hurt.


The two main possibilitys are that the power supply has failed
and that its ignoring the command by the motherboard to turn
on when you press the button, or that the motherboard doesnt
even notice that you have pressed the button anymore.

Its obviously cheaper and easier to try another
power supply than another motherboard.


You can get useful information if you have a multimeter and know how
to use it. But if you havent, the first thing to try a new power supply.

If that makes no difference, check for bad caps on the motherboard.
These are the usually blue or black plastic covered post like things
that stick up vertically from the motherboard surface. The tops
should be flat. If any have bulged or have leaked, thats a bad
cap and likely the reason that the system isnt starting anymore.

If there arent any bad caps visible, try unplugging all the cards, even
the video card. One of those can fail and stop the system starting.
Worth unplugging the drives too, they dont often produce that effect,
but it can happen.

If it looks like a dead motherboard, Asus has a 3 year warranty
and it would be worth trying the motherboard loose on the desktop
just before you return it. You can get a short to case if someone
has dropped a screw into the system and hasnt got it out and
loose on the desktop is the best way to check for a short like that.
Pain to try, but worth it when you have eliminated other possibilitys.

I'm not sure where the "stick a screwdriver in it" came from, but as
an electrician, if I want to "short" something I just use a piece of
wire rated for or exceeding the amperage of the device. In this case a
small wire, 20 to 16 AWG. What I was talking about was shorting pins
13 and 14 on the MB connector from the PSU, by-passing the motherboard
to turn on the PSU.

 

[redkcir]

I'm not sure where the "stick a screwdriver in it" came from, but as
an electrician, if I want to "short" something I just use a piece of
wire rated for or exceeding the amperage of the device. In this case a
small wire, 20 to 16 AWG. What I was talking about was shorting pins
13 and 14 on the MB connector from the PSU, by-passing the motherboard
to turn on the PSU.- Hide quoted text -

- Show quoted text -

I forgot to mention that I am not sure about the pinout on a DELL PSU.
I know they are different from a standard one, just not sure what.
DELL uses a proprietary power supply in some of their rigs which can
fry the MB if a standard PSU is used.

 

[redkcir]

I'm not sure where the "stick a screwdriver in it" came from, but as
an electrician, if I want to "short" something I just use a piece of
wire rated for or exceeding the amperage of the device. In this case a
small wire, 20 to 16 AWG. What I was talking about was shorting pins
13 and 14 on the MB connector from the PSU, by-passing the motherboard
to turn on the PSU.- Hide quoted text -

- Show quoted text -

See this site..

http://www.gideontech.com/content/articles/196/1

 

[Rod Speed]

I'm not sure where the "stick a screwdriver in it" came from,

Its one simple way to eliminate any possibility of
a problem with the physical switch and its wiring.

but as an electrician, if I want to "short" something I just use a piece of
wire rated for or exceeding the amperage of the device. In this case a
small wire, 20 to 16 AWG.

Its easier to use a screwdriver to eliminate any possibility
of a problem with the physical switch and its wiring.

You're only connecting the pins momentarily, not connecting them for long.
If you connect them for long, the system will normally shut down like it does
when you hold the front panel switch in instead of just pressing and releasing it.

What I was talking about was shorting pins 13 and 14 on the MB connector
from the PSU, by-passing the motherboard to turn on the PSU.

What I was talking about was connecting the two header
pins on the motherboard that the front panel switch connects
to. Nothing to do with the ATX connector to the PSU.

 

[Rod Speed]

I forgot to mention that I am not sure about the pinout on a DELL PSU.
I know they are different from a standard one, just not sure what.
DELL uses a proprietary power supply in some of their rigs which can
fry the MB if a standard PSU is used.

Its better to use the wire color than the pin number for that reason.