Do you have any problems with a cold boot ?
I started having problems with my home-built computer, and
coming out of standby, I could hear the hard drive make
multiple attempts to start up (the spinup sound and some
clicks). Eventually, it got bad enough, that when returning
from standby, it rebooted instead. When playing games, the
games became jerky (presumably the video card was doing
"VPU recovers", although there were no messages in Event
Viewer). Also, I could hear a soft "arcing" sound coming
through the computer speakers, just at startup (which
helped give me the idea it was a power problem).
It turned out to be the power supply that was bad.
On opening the power supply (don't touch stuff inside!),
I saw brown deposits on the tops of four capacitors, just
like this picture.
http://upload.wikimedia.org/wikipedia/commons/8/84/PSU_Caps.jpg
So the problem may be related to hardware.
In doing a check in Google, the few power supply failures I've
found for the 8300, are from 2005 or so. In those articles,
they mention the supply is a standard ATX, but the computer
case has no provision for a power switch hole. So if you buy
a standard ATX, it may meet the electrical requirements, but
mechanically may not mesh with the back panel of the computer.
http://groups.google.ca/group/microsoft.public.windowsxp.hardware/msg/cd417a964733fd3e?dmode=source
Power supply pinout is here. I checked, and the colors match
a standard ATX 20 pin. The small four pin shown here, is probably
the floppy connector (P7).
http://support.dell.com/support/edocs/systems/dim8300/sm/techov.htm
PCPower sells replacements, so their unit would likely have
no power switch on it, to match the original. In the picture
of the harness, I see a 1x6 connector used on other systems,
but that would not need to be connected in this case. Since
this is a generic replacement for more than one model of
Dell, not all the connectors would be used when this is
installed.
http://www.pcpower.com/Dell/Dimension/Dimension-8300.html
http://www.pcpower.com/images/products/b/410_Dell2_Harness_3838.jpg
http://www.pcpower.com/downloads/products/diag_S41D.gif
In terms of diagnostic procedures, I'm not sure that a multimeter
is going to give definitive proof of a bad supply. (It is nice when
it does - supplies are supposed to stay within 5% of nominal, so
the acceptable operating range is relatively large.)
One thing I've noticed, that is a "lead indicator" of trouble, on
the two supplies I've had fail on home computers, is the fixed fans
in the computer start to develop more variation in fan speed, when
the power supply is getting flaky. That can happen, before you get
to the point of crashing or rebooting. If a computer has a variable
speed cooling fan, then it may be difficult to notice this. But
I've noticed that you can hear small variations over a matter of a
few seconds (because human pitch detection is pretty sensitive),
even when the hardware monitor measurement of fan speed doesn't seem
to be out of the ordinary.
Paul
