Troublesome PC - Power on and Boot Issues

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Hi all,

I have the following issues of my PC.

**  Powering (or Turning on) the PC can sometimes require switching the
machine on and off 2 times before reaching the BIOS Screen.

** Bios screen has displayed an error message stating that an incorrect CPU
speed is being used, BUT I have been running the PC at the same speed for
over 3 years.

** The CPU normally runs at a speed of 1733 MHZ, although I have reduced it
to 1110 GHZ in order to function.

** Within the past month I have been hearing a noise within the case of my
PC, although I have dusted, vacuumed and used an electronic spray to clean
the insides, and have eliminated this issue.

PLEASE NOTE: A solution which I do not want is to buy a new system. I am
quite content with this system.

Any help would be greatly appreciated!

The following are my PC Specifications

Processor:        AMD Athlon(TM) XP 2100+
Motherboard:   ASUS A7V8X
RAM:               512MB Ram

Re: Troublesome PC - Power on and Boot Issues

Paul L wrote:
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The sound you're hearing, could be coming from the power supply.

I had an Antec power supply (430W?) connected to an A7N8X-E, and
I could hear an "arcing" sound coming from the power supply, just
during initial power up. Once the system started, the arcing stopped.
Eventually, it got bad enough, that the computer crashed in the BIOS.

I opened up the power supply, to find four small leaking capacitors on the
output stage of the supply. The arcing was probably coming from
one of those. I bought a replacement supply, and all was fine.

Like my motherboard, your motherboard runs Vcore from the 5V rail.
There is no ATX12V 2x2 power connector on your board. The power supply
should have a relatively strong 5V rating, to help with that. (So looking
at the label of the supply, 5V @ 25A would give you some margin.)

+3.3V @ 30A, +5V @ 28A, +12V1 @ 14A, +12V2 @ 15A, -12V @ 0.5A, +5VSB @ 2A

It is easy to find supplies which would be a bad match for your system.
This one is particularly weak on +5V. This might make a good supply
for a Core2 Duo system, but not for a system like yours. (The reason
this one is weird, is because it is fanless. It is a high efficiency
design, so there isn't a lot of waste heat. But there isn't a lot of
capacity on the output, either.)

+3.3V @ 20A, +5V @ 14A, +12V1 @ 14A, +12V2 @ 13A, -12V @ 0.5A, +5VSB @ 2.5A

So perhaps your problem is related to the power supply, which is a
frequent failure point in PCs.

A new supply cost me about $60, because I wanted something I could
continue to use. I'm using that replacement supply right now, on the machine
I'm typing on.

If the existing power supply is relatively new, it could have a warranty.
In my case, the supply was old enough, I just opened it up for
a peek, without intending to take it all apart and try and fix it.
I try not to poke around inside there, because on the primary
side, there is high voltage DC rectified from the AC mains. And
both the joule rating and the voltage involved, is scary enough,
to keep me from getting too curious. But I was able to see the
orange-brown deposits on top of four of the capacitors.

You can see four leaking in this one. This is not the same
as my supply. You can see at least one other capacitor, where
the top of the cap is beginning to bulge. The top should be
flat on each one. Bulging means pressure is building inside.

An Asus motherboard will drop the FSB speed, in response to a crash.
They call it "overclocking recovery", but it can even happen to a
computer running at stock speed, that crashes for some reason. The
BIOS returns a number of settings to default (on one of my boards,
I have to remember to set the storage interface to the correct
setting, before it can boot again). My current, non-Asus motherboard,
has a different scheme - when that one is in trouble, I have to
press the reset button three times in a row, and then the BIOS
resets to defaults. But at least it doesn't do the default thing
whenever the mood strikes it. It takes a concerted effort on
my part, to make it drop to safe (default) conditions.

Good luck,

Re: Troublesome PC - Power on and Boot Issues

On Sat, 09 May 2009 02:25:03 GMT, "Paul L"

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You need to find the source of that noise.  "Probably" a fan
failing that needs replaced, though not necessarily related
to your present problem.

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As Paul #2 mentioned, this could be a PSU failure.  Examine
the board for capacitor failure, and the PSU too if you feel
comfortable opening it after lettting it sit for a couple
minutes disconnected from AC.  If it turns out to be a PSU
failure, get one with a high ratio of 5V:12V current, which
would typically be one of old, last generation design.  

I do think it most "likely" that you have a 5V rail
capacitor(s) that have failed in your PSU.  If you have the
skill and a soldering iron it may not take long or be
expensive to fix.

Re: Troublesome PC - Power on and Boot Issues

Hi Both Paul # 2 and Kony,

Thank you very much for your replies..

Since I have written this post almost a month has past since I have returned
to my parents house to use this PC.

There are no fan noises since we have cleaned the insides of the PC.

My mum claims that the error is still occuring, but I have powered on the PC
with no issues at the moment. If I do notice anything tonight though I will
proceed to take out my power supply and install an alternate one.

Thanks again..


- Paul
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Re: Troublesome PC - Power on and Boot Issues

Paul L wrote:
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