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Today's Topics:
1. help diagnosing PC issue: suspect power supply (Brett Russ)
2. Re: help diagnosing PC issue: suspect power supply
(Chuck Anderson)
----------------------------------------------------------------------
Message: 1
Date: Sat, 29 Sep 2012 14:32:05 -0400
From: Brett Russ <bruss@alum.wpi.edu>
Subject: [Wlug] help diagnosing PC issue: suspect power supply
To: Worcester Linux Users Group <wlug@mail.wlug.org>
Message-ID:
<CAGcHgFNRd2jLrywD977a0jZChqEREnNBt529abY0=fh2OU5FAA@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Hi,
I'm trying to diagnose a home built PC running fine since 2007 but lately
starting to act odd. Here are the system specs:
Intel Core 2 Duo 1.8GHz cpu
Asus P5B Deluxe mobo
Nvidia 7900GS graphics card
Kingston KHX6400 2x1GB DDR2 memory
Sparkle ATX 400W power supply
3x 1TB SATA HDDs
1x SATA DVD-RW
$ uname -a
Linux spider 3.0.0-25-generic #41-Ubuntu SMP Mon Aug 13 17:58:59 UTC 2012
x86_64 x86_64 x86_64 GNU/Linux
$ cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=11.10
DISTRIB_CODENAME=oneiric
DISTRIB_DESCRIPTION="Ubuntu 11.10"
$ uname -a
Linux spider 3.0.0-25-generic #41-Ubuntu SMP Mon Aug 13 17:58:59 UTC 2012
x86_64 x86_64 x86_64 GNU/Linux
What recently changed:
i) replaced monitor, last one died
ii) (carefully) vacuumed the dust from inside. Kept hand on case chassis,
didn't touch any PCB/chips, etc.
Here are the symptoms:
1) first started seeing BIOS claims of bad CMOS checksum at boot time.
Immediately suspected the CMOS battery, replaced it and reset CMOS settings
but I continue to see this. This is the one symptom that I can't yet
place, unless it's simply a bad replacement battery.
2) next started seeing the monitor fail to wake up after entering power save
3) powering on the PC shows issues:
3a) often the monitor won't wake at boot
3b) the bios often doesn't finish POST, gets stuck at splash screen
3c) bios settings often don't survive across power cycles (possibly related
to #1--battery issue?)
3d) bios doesn't always give the affirmative beep (likely same symptom as
3a, 3b)
3e) a cold power on or reset can take several "tries" before the system
stays on. I.e. fans will spin up, then spin down, one to three times
before staying on. When this happens it's pretty much guaranteed that it
won't boot successfully.
4) system will freeze to user input while up. I.e. once I get Linux
booted, as long as I disable monitor power save it will stay running for a
while, but I observed it stopped responding to KB and mouse input earlier
this morning.
Here's what I've tried:
a) reseated both DIMMs, reproduced issues; tried with just one DIMM,
repro'd; tried other DIMM, repro'd
b) reseated graphics card, repro'd; removed graphics card (now headless),
repro'd problem 3e
c) reseated CMOS battery (CR2032), repro'd
d) pulled all non-essential cables and internal connections, including
power and SATA cables from all drives, repro'd
e) updated BIOS to latest version, repro'd
Unfortunately I don't have another ATX power supply to try, but was
thinking of buying one. I might also try an old PCI video card, but I
suspect due to repro (b) above that it's not the cause.
Anyone have any other insights or agree it sounds like a bad PS? I still
can't explain symptom (1), will probably buy another battery to be sure.
Five years seems like an old PC, but I'm not a gamer so this suits me fine.
Thanks,
Brett
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Message: 2
Date: Sat, 29 Sep 2012 18:19:47 -0400
From: Chuck Anderson <cra@WPI.EDU>
Subject: Re: [Wlug] help diagnosing PC issue: suspect power supply
To: Worcester Linux Users Group <wlug@mail.wlug.org>
Message-ID: <20120929221947.GH12327@angus.ind.WPI.EDU>
Content-Type: text/plain; charset=us-ascii
On Sat, Sep 29, 2012 at 02:32:05PM -0400, Brett Russ wrote:
> Sparkle ATX 400W power supply
> Anyone have any other insights or agree it sounds like a bad PS? I still
> can't explain symptom (1), will probably buy another battery to be sure.
> Five years seems like an old PC, but I'm not a gamer so this suits me fine.
I agree that the power supply is suspect. You can measure the voltage
on a spare power supply hard drive connector, there should be 12v from
black to yellow, and 5v from black to red. If that checks out, you
should measure from the motherboard ATX connector as some of the other
voltages may be out of spec. You can find the standard ATX pinouts
and voltages online. Finally, you can test with the power supply
completely disconnected from the PC. Again, you can find instructions
online for how to do that, as it requires a jumper wire for the power
supply to power on.
Alternatively, it may be easier to just try a replacement.
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