Power supply problem?

[Paul]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Hi,

I've been having problems which I'm pretty sure are the fault of the
power supply, but i'd like a second opinion!!!

Basically when I switch my machine on the fans spin up for about 1
second, then the whole thing dies. if i press the power button again
nothing happens at all......only if I pull out the plug at the wall
and plug it back in will it repeat the above symptoms.

So I guessed the power supply must be tripping out, so I disconnect
the power to the hard drive, dvd drive, cpu fan and unplug my usb
modem and try again.

This time the machine gets as far as the bios and then shuts
down.......I reconnect the hard drive, and after a few attempts the
machine boots up normally.

I ran a monitoring utility to keep an eye on the voltages, but they
seem fine......even when I really get the processor drawing alot of
current it does'nt fall over.

Am I right in thinking the power supply is faulty?.........I'm
guessing the 12v side is failing and unable to supply the required
current to start the machine from cold

Thanks

 

[Guest]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

On Fri, 26 Aug 2005 18:15:42 +0100, Paul
<booke23@hotmail.com> wrote:

>
>Hi,
>
>I've been having problems which I'm pretty sure are the fault of the
>power supply, but i'd like a second opinion!!!
>
>Basically when I switch my machine on the fans spin up for about 1
>second, then the whole thing dies. if i press the power button again
>nothing happens at all......only if I pull out the plug at the wall
>and plug it back in will it repeat the above symptoms.

Yes that's a strong sign of a PSU problem.

>
>So I guessed the power supply must be tripping out, so I disconnect
>the power to the hard drive, dvd drive, cpu fan and unplug my usb
>modem and try again.
>
>This time the machine gets as far as the bios and then shuts
>down.......I reconnect the hard drive, and after a few attempts the
>machine boots up normally.

The parts you removed, are a relatively low % of total
system power, and it is expected that their removal alone
may not make enough difference. This is a situation where
it would be good to take PSU readings with a multimeter
while the system is turned on, up until it shuts down.
Particularly the 5V and 12V rails.

>
>I ran a monitoring utility to keep an eye on the voltages, but they
>seem fine......even when I really get the processor drawing alot of
>current it does'nt fall over.
>
>Am I right in thinking the power supply is faulty?.........I'm
>guessing the 12v side is failing and unable to supply the required
>current to start the machine from cold

yes, it seems either the cold start surge or the cold temp
of the PSU itself is a problem... either way the odds are
high you need another PSU, preferribly one name-brand with
ample reserve capacity.

 

[Guest]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Your explanation sounds reasonable.

--
DaveW


"Paul" <booke23@hotmail.com> wrote in message
news:1125076536.54b1e4a59fd857080c931072a8229713@teranews...
>
> Hi,
>
> I've been having problems which I'm pretty sure are the fault of the
> power supply, but i'd like a second opinion!!!
>
> Basically when I switch my machine on the fans spin up for about 1
> second, then the whole thing dies. if i press the power button again
> nothing happens at all......only if I pull out the plug at the wall
> and plug it back in will it repeat the above symptoms.
>
> So I guessed the power supply must be tripping out, so I disconnect
> the power to the hard drive, dvd drive, cpu fan and unplug my usb
> modem and try again.
>
> This time the machine gets as far as the bios and then shuts
> down.......I reconnect the hard drive, and after a few attempts the
> machine boots up normally.
>
> I ran a monitoring utility to keep an eye on the voltages, but they
> seem fine......even when I really get the processor drawing alot of
> current it does'nt fall over.
>
> Am I right in thinking the power supply is faulty?.........I'm
> guessing the 12v side is failing and unable to supply the required
> current to start the machine from cold
>
> Thanks

 

[Paul]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Thanks for your views.

I got a replacement power supply today and fitted it. The machine is
now running perfectly............case solved.