PSU problem?

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Ok, my computer has become extremely temperamental so I'll just post
what's been happening and hopefully someone can shed some light and
advise me.

This all started when I came back to my pc and pressed escape for some
task I've forgotten. The computer was unresponsive and something in
the hardware just let out a beep when I pressed. I thought I'd just
leave it alone for a while, but within a few minutes my pc was letting
out a continuous beeping - I left it a few more minutes and then just
restarted it by the button on the box

When I tried to turn it on again it just froze on a blank screen. After
repeating this seemingly endlessly, I noticed that it froze on the
blank screen immediately after the bit of text which said "verifying
DMI pool data...", and also that as the computer started there were
beeps (I thought it was three short beeps, all very close together).

Not knowing much about hardware, I cracked out the Phillips screwdriver
and opened the box up. I poked around a bit, didn't really change
much, and then wired back the monitor and the mouse and started it up
again. This time it worked!
Not wanting to tempt fate, I immediately made for my important files
and tried to get them backed up onto a DVD. For some reason this
wouldn't work (I think the error message was something very generic,
like "error, XP cannot copy this file).

I turned my pc off by the button on the box, and tried to turn it on
again, but this time it was totally unresponsive. Nothing happened.

After a minor heart attack I unplugged all the external stuff again,
and then rebooted it. Again it worked, and instead of backing up stuff
through DVD, I plugged the modem in and backed it up via the network to
my Dad's shiny new laptop. Half way through messing around and
looking on the net for a solution, my keyboard (which was plugged into
a USB port) locked out.

I rebooted (think I just restarted through XP rather than going through
the whole rigmarole of unplugging everything). This time my keyboard
worked but my graphics card didn't. I was seeing XP in some
ridiculously small resolution with about 16 colours. It occurs to me
now, that possibly in my earlier attempt to backup, there had been
other components that XP had been trying to install such as my TV card.

Next time I restarted, I didn't risk using my keyboard - I just had
my monitor and my mouse plugged in at the back, and it worked (sort of)
ok. I haven't tried since (been busy with other stuff, and my PC has
been off for a couple of days).

Does anyone have any idea what I should do?

N.b. I *think* it might be a PSU problem. This would seem to fit,
because it explains why my DVD writer drive wasn't working, why
sometimes components aren't working properly, why my PC sometimes
won't turn on. I also have had a kind of continuing issue with my USB
pen drive not connecting properly (first XP recognises the new
hardware, then I click on My Computer and see it, but windows kind of
freezes, and is pretty unresponsive until I unplug it). I've had a
similar issue with my digital camera, which is also connected via USB.
It's also been suggested to me that it's a problem with my

Obviously if it's a PSU problem, I should be able to just order a new
one, but I want to be sure that it IS that problem, before a I buy a
new one. Thanks

Re: PSU problem? wrote:

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If you have a digital multimeter, measure the voltages, but don't rely
on the BIOS or any system monitoring  software for this because it's
often very inaccurate.  Even the cheapest digital meter is more than
accurate enough, but analog meters are another story.  Another thing to
try is running the computer with the side panel off, preferrably with a
tabletop fan blowing into it, because if the problem is a marginal PSU,
then cooler temperatures will often make it more reliable.  Another
thing to do is try to diagnose the hardware as well as possible in DOS,
such as with the free diagnostics at and, running each for several hours.  Another really good
memory diagnostic is shareware at

Re: PSU problem?

thanks larry! i'm getting hold of a digital multimeter, and i'm
currently running the diagnostic from

what kind of information will these diagnostic progs give me?
diagnosing the memory is what, diagnosing the motherboard? the cpu?

thanks again for you time.

Re: PSU problem?

alexei wrote:

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MemTest86 and MemTest+ check just the memory, but memory is probably
some of the worst-quality hardware sold now because so much of it is
made with untested chips -- Google for "UTT memory" to read of the
problems with this, and even major memory makers, including Mushkin and
Corsair, now use UTT chips.  One that says it doesn't is Kingston, but
they buy whole wafers and slice and test them themselves, and their
track record hasn't been very good with me -- 8 out of 11 or 12 of
their 512MB PC3200 ValueRAMs failed either MemTest86 or Gold Memory.

To test the hard drives, use either the drive manufacturer's diagnostic
or Hitachi Global Storage Technology's ( Drive Fitness
Test, which can do read testing of
any brand of drive.,, and
should have other diagnostics and burn-in programs.

Re: PSU problem? wrote:

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You can check that if it happens again at

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Likely you gave it enough time to cool down.

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The fault may well be temperature sensitive.

Check the cpu fan and ensure that it isnt all clogged up with fur.

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More evidence of a warmup fault.

You may be able to let it cool down and copy
the uncopied stuff on the second attempt.

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That is certainly one possibility.

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Yes, but a failing motherboard will produce the same effect.

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That may be a separate issue.

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Yes, it can be either.

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That is harder. With some PSUs the only real way to see if the
PSU is at fault is to try another known good one with what you
have to test it with. While you can use a multimeter to check the
voltages, if its got a high ripple level on one rail, that isnt that
easy to work out with a multimeter, you really need a CRO
to see that properly and they cost a lot more than a PSU.

Check the motherboard for bad caps. These are the usually
blue or black plastic covered post like things that stick up
vertically from the motherboard surface. The tops should
be flat an if any of them have bulged or have leaked, thats
a bad cap and its usually best to replace the motherboard.

Check the cpu temp with something like Everest.

Re: PSU problem? wrote:

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You've probably overheated (not you... :) )

Don't worry about your weird screen problem, it probably was just safe mode.

poly-p man

Backprobe the power connectors anyway. Make sure that they're appoximately
There's no place like ~
Help!! I'm being Nibbled to death by cats!!!
"Cardboard is the scourge of humanity, but oh, so very tasty."

primary harddrive overheating??!

To Rod Speed:

I hear what you're saying about leaving it might mean it'd cool down,
but it was turned off for approx 20 seconds while i quickly whipped the
power cord off and then plugged it back in again. if overheating was
the issue, i assume a half minute wouldn't be enough time?

All the fans seem a little dusty, but nothing incredible. i think
they're probably ok

I left my PC running diagnostics for over a day (Goldmemory; it came up
with no errors), with the case open, but with no fan running onto it,
as i had been.

Temps currently are

Motherboard: 30C 86F
CPU: 42C 108F

which seem fine???

my secondary harddrive is 38C 100F (again this seems fine), but my
primary harddrive, according to everest is a bizarre 88C 190F!

this seems way too high!

ok, i'm doing this as i type, another test came up as 103C for my main

Is there any way this is inaccruate?!?!

The new freeware is called HDDthermometer!?

Re: primary harddrive overheating??!

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I didnt mean overheating in the sense you comment on below,
its more likely to be a warmup fault with the motherboard with
a dry joint or cracked trace, and that 20 secs can be enough.

On the other hand, it looks more complicated than that now, see below.

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Yeah, they're fine from the temps below.

And they have to be pretty clogged with fur to be a problem, not just dusty.

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Thats interesting, that doesnt look like a warmup fault.

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Yep, no problem with those.

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Yeah, that must be wrong. You can get that with some Maxtors.

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Yeah, the sensor cant be connected, its completely meaningless.

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Nope, just ignore it.

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Did you see any bad caps ?  Presumably you would have said if you had.

Can still be a failing motherboard or power supply.
Its obviously cheaper to try a new power supply.

Re: primary harddrive overheating??!

thanks for you time rod, and reading back over my last post, sorry for
being so frantic before.

yeah you're right, i couldn't see anything wrong with the caps.

so it's either a failing motherboard or a failing PSU?

and am i right when interpreting one of your earlier posts that a
multimeter will either

a) show me that i have a PSU problem when i do
b) show me that i don't have a PSU problem when i do
c) rightly show me there's nothing wrong with the power supply

in other words, it's worth doing because it could show that the power
supply is dodgy? i can pick one up (fairly) easily tomorrow.

i think my money's on the power supply being dodgy, which is good news
for my wallet - how much would a reasonable motherboard cost me?

thank you again

Re: primary harddrive overheating??!

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No problem, it can be a complete pain in the arse when things arent reliable.

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Yeah, it could be something else, but very unlikely.

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Nope, I meant that a multimeter isnt that great for working
out if a PSU is fine with some PSU faults, a known working
PSU is a better way to prove whether the PSU is at fault or
not, particularly when the problem is intermittent as yours
clearly is if it ran the memory checker fine for a day.

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I wouldnt bother, mainly since it ran the memory checker fine for a day.

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Varys quite a bit depending on what you currently have. You'd need one that
can take the current cpu and memory and I dont know what you have currently.

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