Power supply, but no power???

I believe a power surge toasted my power supply the other day, so I
replaced it with a new 350W ATX PSU. After removing the burnt psu, I
screwed the new psu into the case, hooked the ATX power supply to the
motherboard, and hooked up power for various components (HD's,
CD-ROM's). The motherboard's pilot light turns on to signify that it's
getting power, but when I press the case's power button... nothing. No
fans, no sound, no disk spinning, no signs of life at all (besides that
pilot light being on). Am I forgetting something?

I inspected all the components (and the motherboard and cpu) and none
of them appear (or smell) to have been damaged.

Where do I go from here? Any help would be appreciated.

Motherboard: DFI AK70 (AMD 750 cpu).

-U.

PS, forgive the cross-post -- I don't have a news host and google is
giving me errors when I try to post to some of these groups
individually.

On Thu, 07 Apr 2005 13:28:25 -0700, U. Cortez wrote:

I believe a power surge toasted my power supply the other day, so I
replaced it with a new 350W ATX PSU. After removing the burnt psu, I
screwed the new psu into the case, hooked the ATX power supply to the
motherboard, and hooked up power for various components (HD's,
CD-ROM's). The motherboard's pilot light turns on to signify that it's
getting power, but when I press the case's power button... nothing. No
fans, no sound, no disk spinning, no signs of life at all (besides that
pilot light being on). Am I forgetting something?

Where do I go from here? Any help would be appreciated.

Double check the power button plug is plugged into the proper pins. If it
is and it still doesn't work, unplug it and short the 2 power button pins
on the MB for a second. It should turn on power. If not, then it may be a
bad MB or bad PSU. If it does come on that way, then the problem is in the
leads to, or the power button itself.

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
My server http://wesnewell.no-ip.com/cpu.php
Verizon server http://mysite.verizon.net/res0exft/cpu.htm

If the power supply is toasted, then you have an important
fact. What inside the power supply is blackened? However if
just assuming it was some surge and if assuming it was the
power supply, then you have much to learn. The power supply
'system' is many components. A power supply is only one
part. You could swap things forever until something works.
Or discover in but two minutes what is and is not damaged.

Procedures and concepts are provided in two previous posts:
"Computer doesnt start at all" in alt.comp.hardware on 10
Jan 2004 at
http://tinyurl.com/2t69q and
"I think my power supply is dead" in alt.comp.hardware on 5
Feb 2004 at
http://tinyurl.com/yvbw9

Just because a light is on does not mean sufficient voltage
is available. Lights can illuminate; fans spin; and still the
power supply is not working. But then a power supply might
shutdown because something else is defective. There is no
faster analysis than using a 3.5 digit multimeter. Two
minutes should suggest what is defective. Furthermore,
numbers that mean nothing to you could be the 'smoking gun'
solution for those with better knowledge. Without numbers,
you cannot tap the best sources on the other side of your
computer screen.

"U. Cortez" wrote:
I believe a power surge toasted my power supply the other day, so I
replaced it with a new 350W ATX PSU. After removing the burnt psu, I
screwed the new psu into the case, hooked the ATX power supply to the
motherboard, and hooked up power for various components (HD's,
CD-ROM's). The motherboard's pilot light turns on to signify that it's
getting power, but when I press the case's power button... nothing. No
fans, no sound, no disk spinning, no signs of life at all (besides that
pilot light being on). Am I forgetting something?

I inspected all the components (and the motherboard and cpu) and none
of them appear (or smell) to have been damaged.

Where do I go from here? Any help would be appreciated.

Motherboard: DFI AK70 (AMD 750 cpu).

Thanks for the reply.

If the power supply is toasted, then you have an important
fact. What inside the power supply is blackened? However if
just assuming it was some surge and if assuming it was the
power supply, then you have much to learn.

Yes, I know the PSU is toasted. Whether or not anything else is
damaged is what I don't know. I haven't bothered opening up the power
supply itself... and other than recognizing what resistors and
capacitors are, I'm not real familiar with the components _within_ a
psu. I don't know what caused the problem, but the circuit breaker was
thrown for the entire room (not only did computer shut down, all the
lights and clocks turned off, etc). However, it wasn't a brown- or
black-out.

There is no faster analysis than using a 3.5 digit multimeter.
Two minutes should suggest what is defective.

That'll be my next step. Thanks for the info.

Wes Newell wrote in message news:pan.2005.04.07.21.06.50.364178@TAKEOUTverizo n.net...
On Thu, 07 Apr 2005 13:28:25 -0700, U. Cortez wrote:

I believe a power surge toasted my power supply the other day, so I
replaced it with a new 350W ATX PSU. After removing the burnt psu, I
screwed the new psu into the case, hooked the ATX power supply to the
motherboard, and hooked up power for various components (HD's,
CD-ROM's). The motherboard's pilot light turns on to signify that it's
getting power, but when I press the case's power button... nothing. No
fans, no sound, no disk spinning, no signs of life at all (besides that
pilot light being on). Am I forgetting something?

Where do I go from here? Any help would be appreciated.

Double check the power button plug is plugged into the proper pins. If it
is and it still doesn't work, unplug it and short the 2 power button pins
on the MB for a second. It should turn on power. If not, then it may be a
bad MB or bad PSU. If it does come on that way, then the problem is in the
leads to, or the power button itself.

try taking all of the components out of your computer and runniong the
system out of the case, at least this mught remove the chance that
something is grounded.

If the power supply is toasted, then you have an important
fact. What inside the power supply is blackened?

Just for kicks, I opened up the old psu and it looks like a couple
capacitors blew. I'm not going to be all that dissappointed to see
that psu taken to the morgue, as it was old and cheap and possibly
under-powered. However, I won't be a happy puppy if my motherboard got
toasted too. I'll probably test it today and see...

-U.

The failed capacitors (and probably failed diodes) is
consistent with the circuit breaker tripping. Now here is
where we discover the technical knowledge of the guy who
selected that supply. Asian manufacturers have learned there
are many computer assemblers masguading as electrically
knowledgeable. So power supplies that are missing essential
functions are now dumped into the market at greater profit.
You know them by their lower price. These are functions where
were defacto standard even 30 years ago.

Any power supply that fails must not damage any other
computer part. But if the essential function was missing in
that supply, then you now may have other damage. A minimally
acceptable supply sells for about $65 full retail. Supplies
missing essential functions such as overvoltage protection
sell for less, earn greater profits for their manufacturers,
and can then cause disk drive and motherboard failure.

You have no other failures inside the computer IF the
original power supply was minimally acceptable; not selected
by a 'bean counting' computer assembler.

"U. Cortez" wrote:
Just for kicks, I opened up the old psu and it looks like a couple
capacitors blew. I'm not going to be all that dissappointed to see
that psu taken to the morgue, as it was old and cheap and possibly
under-powered. However, I won't be a happy puppy if my motherboard got
toasted too. I'll probably test it today and see...

-U.

On Fri, 08 Apr 2005 12:22:21 -0400, w_tom wrote:

Any power supply that fails must not damage any other
computer part. But if the essential function was missing in
that supply, then you now may have other damage. A minimally
acceptable supply sells for about $65 full retail. Supplies
missing essential functions such as overvoltage protection
sell for less, earn greater profits for their manufacturers,
and can then cause disk drive and motherboard failure.

I think overload protection is a requirement for UL approval. And I've
never spent over $24 for a PSU.:-)

I've used a 600W similar to this for over a year now on my A64 system. But
it was $24 when I bought mine.

http://store.mrtechus.com/60ulapatxcop.html

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
My server http://wesnewell.no-ip.com/cpu.php
Verizon server http://mysite.verizon.net/res0exft/cpu.htm

It sounds like the power surge also toasted your motherboard. This
frequently happens when an inexpensive power supply unit is used in a
system. It passes the surge on to the motherboard, rather than absorb it
entirely.

--
DaveW



"U. Cortez" wrote in message
oups.com...
I believe a power surge toasted my power supply the other day, so I
replaced it with a new 350W ATX PSU. After removing the burnt psu, I
screwed the new psu into the case, hooked the ATX power supply to the
motherboard, and hooked up power for various components (HD's,
CD-ROM's). The motherboard's pilot light turns on to signify that it's
getting power, but when I press the case's power button... nothing. No
fans, no sound, no disk spinning, no signs of life at all (besides that
pilot light being on). Am I forgetting something?

I inspected all the components (and the motherboard and cpu) and none
of them appear (or smell) to have been damaged.

Where do I go from here? Any help would be appreciated.

Motherboard: DFI AK70 (AMD 750 cpu).

-U.

PS, forgive the cross-post -- I don't have a news host and google is
giving me errors when I try to post to some of these groups
individually.

Well last night I tested the power supply (with it just plugged into
the motherboard) and all the voltages were in their acceptable ranges.
So, I started to plug things back in 1 at a time, and... it all
worked! I'm typing this now on my working computer. There must have
just been a loose connection or something when I first installed my new
PSU. But when I took my computer apart (yes, I mean completely apart
-- even took the cooler off the cpu) and put it back together I must
have secured whatever was keeping it from starting up before.

So I guess the failed motherboard was a false alarm (whew!). Now the
first thing on my agenda: get a UPS so I don't have to worry about
circuit trips blowing my PSU again.

Thanks all for the help!

-U.