Power Supply Problem

I am experiencing problems in starting my machine. Recently pressing
the 'on' button causes the front lights to momentarily come on then
extinguish and the power supply does not start. It gives the
impression that the 'relay' is not holding in (I know there isn't a
mechanical relay but I hope you get the idea). Generally trying a
secend time starts the machine but today it required four attempts.

The power supply is (I think) an Antec as it came preinstalled in the
Antec Sonata case. Is this indicative of a failing power supply?
Other than the starting problem there are no other indications of a
problem.

On Wed, 26 Dec 2007 07:09:03 +0000, Edward W. Thompson
<thomeduk1@btopenworld.com> wrote:

>I am experiencing problems in starting my machine. Recently pressing
>the 'on' button causes the front lights to momentarily come on then
>extinguish and the power supply does not start. It gives the
>impression that the 'relay' is not holding in (I know there isn't a
>mechanical relay but I hope you get the idea). Generally trying a
>secend time starts the machine but today it required four attempts.

Sometimes, a motherboard or other connected part failure
will cause a very high load on the PSU and that results in
it being inable to handle the (nearly shorted) load and shut
off.

More often, it is a sign the power supply has failed.

Using a multimeter to monitor voltages might help, sometimes
it can indicate an out of spec condition but not always in
this situation.


>
>The power supply is (I think) an Antec as it came preinstalled in the
>Antec Sonata case. Is this indicative of a failing power supply?
>Other than the starting problem there are no other indications of a
>problem.

I would suspect the PSU capacitor(s) have failed. After
leaving the PSU unplugged for several minutes you might
inspect it, particularly the larger capacitors around the
point where the exiting wiring harness is soldered to the
board.

A bit more specifics might help like the history of the
system, how long it had ran with this PSU, more details on
which Antec PSU it is, and a concise list of the major parts
in the system.

In some cases it might be a problem if you had added an
addt'l load on the 5VSB circuit, if the motherboard were
jumpered (or always uses) 5VSB rail for powering PS2 or USB
peripherals and you had added something. In that case
unplugging these parts might lessen the load on 5VSB and the
system would then more regularly POST and boot.

On Wed, 26 Dec 2007 03:39:02 -0500, kony <spam@spam.com> wrote:

>On Wed, 26 Dec 2007 07:09:03 +0000, Edward W. Thompson
><thomeduk1@btopenworld.com> wrote:
>
>>I am experiencing problems in starting my machine. Recently pressing
>>the 'on' button causes the front lights to momentarily come on then
>>extinguish and the power supply does not start. It gives the
>>impression that the 'relay' is not holding in (I know there isn't a
>>mechanical relay but I hope you get the idea). Generally trying a
>>secend time starts the machine but today it required four attempts.
>
>Sometimes, a motherboard or other connected part failure
>will cause a very high load on the PSU and that results in
>it being inable to handle the (nearly shorted) load and shut
>off.
>
>More often, it is a sign the power supply has failed.
>
>Using a multimeter to monitor voltages might help, sometimes
>it can indicate an out of spec condition but not always in
>this situation.
>
>
>>
>>The power supply is (I think) an Antec as it came preinstalled in the
>>Antec Sonata case. Is this indicative of a failing power supply?
>>Other than the starting problem there are no other indications of a
>>problem.
>
>I would suspect the PSU capacitor(s) have failed. After
>leaving the PSU unplugged for several minutes you might
>inspect it, particularly the larger capacitors around the
>point where the exiting wiring harness is soldered to the
>board.
>
>A bit more specifics might help like the history of the
>system, how long it had ran with this PSU, more details on
>which Antec PSU it is, and a concise list of the major parts
>in the system.
>
>In some cases it might be a problem if you had added an
>addt'l load on the 5VSB circuit, if the motherboard were
>jumpered (or always uses) 5VSB rail for powering PS2 or USB
>peripherals and you had added something. In that case
>unplugging these parts might lessen the load on 5VSB and the
>system would then more regularly POST and boot.

Thanks for your thougts. The PSU is now about 4 years old and I have
not added any additional loads to the system, at least not for the
past 3/4 months when I installed a new AGP video card that required a
discrete power supply. The problem I have is not consistent,that is
the start up problem does not occur every day but happens sufficiently
often to start ringing 'alarm bells', hence my enquiry.

I would have thought component failure would mean th 'fault' would be
consistent but perhaps not. I suppose the only course is to let it
continue and no doubt eventually one day it simply won't start and a
replacement PSU will be the 'fix'. I guess the PSU is not really a
serviceable items, at least not for the ' electronic challenged' among
us :-).

On Thu, 27 Dec 2007 07:51:44 +0000, Edward W. Thompson
<thomeduk1@btopenworld.com> wrote:


>Thanks for your thougts. The PSU is now about 4 years old and I have
>not added any additional loads to the system, at least not for the
>past 3/4 months when I installed a new AGP video card that required a
>discrete power supply. The problem I have is not consistent,that is
>the start up problem does not occur every day but happens sufficiently
>often to start ringing 'alarm bells', hence my enquiry.
>
> I would have thought component failure would mean th 'fault' would be
>consistent but perhaps not. I suppose the only course is to let it
>continue and no doubt eventually one day it simply won't start and a
>replacement PSU will be the 'fix'. I guess the PSU is not really a
>serviceable items, at least not for the ' electronic challenged' among
>us :-).


The PSU would be the first suspect, but failure of other
parts could also cause the problem. Thus an inspection of
the PSU and taking voltage measurements might help though
with some gradual PSU failures the voltages don't look too
far off. If no clear fault can be found I would then try
another PSU first, but also inspecting the larger capacitors
on the motherboard, particularly around the CPU socket.