I'll try and be quick as this computer tends to shut-down a lot.
Recently I've been having problems with my PC either failing to boot, or
'dying' after about 5 mins or so of use. I thought this was a problem with
the motherboard, so went and got a shiny new one (complete with new
processor and memory as my old stuff doesn't work with it) and stuck it in.
Anyway, in the mean-time I've been using my wife's PC, and tonight it
started to exhibit the same behaviour as my old PC, though the 'hangs' were
slightly different. The same stuff happening to 2 different PC's leads me to
suspect the problem might be fluctuations in the domestic supply. Is there
any way I can check this? It was fine up until approx a month ago, but as
far as I can tell, nothings changed.
Also, changes in the supply don't appear to be obvious (i.e. the lights
don't dim when the PC's have problems). Any suggestions?
I'd say this was unlikely. The switch mode PSUs in PCs have a very wide
input voltage range. If the fluctuations were large enough to cause
these effects, you'd be seeing other evidence, such as blowing/dimming
lightbulbs and the like.
It's more likely both the machines are infected with a virus (did you do
a full reinstall when you replaced the motherboard?), or are
experiencing some EMI from an external source.
Are you running the same operating system (I use the term loosely if
it's a Microsoft product) on both systems?
Otherwise I would think about the power supply in a machine having
problems. Possible but less likely in two machines unless they happen
to have the same kind of case and PSU.
If you have upgraded the motherboard and CPU and kept the case then it
is possible that the PSU is not adequate. This can certainly provoke
the symptoms that you are seeing.
Otherwise you can contact the electricity supplier and ask them to put
a monitor on the mains supply.
Shut down entirely or reboot?
Sure it's not a virus....?
If you are using XP, have you checked the event logs ?
Did you change the PSU as well? I'd suspect that before the mains
supply, unless other devices are playing up too :)
Hooking a recording meter to the mains supply is the only way to
monitor it really. The supply companies used to investigate and hook up
such a meter in cases where they thought it neccessary. I don't know if
they still do.
I notice you're running an MS OS....
Could have been a recent spike taking out both power supplies, it
doesn't take much. If this is the case the damage is done and you
won't have seen it happening.
The other possibility is, as you suggest, fluctuations in the supply.
These can be very slight, almost unnoticable except to your PC
Perhaps your next purchase might be a online UPS with filtered
Thanks for ALL replies (too many to reply to individually!).
My 'original' PC worked fine in the last flat for 3 years, and in this for 4
months. Been playing up for the last 3 or so weeks. Then I got the wife's pc
back from her parents (on loan), and it's started misbehaving tonight. New
M/B appears to be dead, so currently re-installed old m/b back in to send
this message! It's currently working.
I have an even older PC used as a server which seems to be OK when the other
two play up, though it's power draw is a lot less (Pentium as opposed to
Other alternative is the Uni lecturer next door is experimenting with EM
pulses! The thing that's got me confused is why it'd start happening, and
then affect 2 PC's. A virus would explain why a computer would hang, but not
why it wouldn't POST (which has also happened to my PC sometimes, and was
why I thought the M/B was the problem).
You could find out how long your neighbour has been experimenting with EM
pulses and see if it correlates to your PCs starting to misbehave and die.
I would tend to suspect that would be the cause of damage to your computers
rather than power surges.
I'd also be rather alarmed at a neighbour experimenting with EM pulses
without any thought for safety considering they're known for causing damage
to electronic equipment and hope you nor the rest of your family have to
rely on heart pacemakers!
It would be very useful to know how whether he is experimenting with
electomagnetic pulses, or whether he is experimenting with
Electromagnetic Pulse (EMP), aka NEMP (Nuclear Electromagnatic
Pulse) ie. the electromagnetic field generated when a nuclear device is
detonated. No, I'm not suggesting he's playing with nukes in his back
garden, but EMP simulators are in existence, and if he's playing at making
one, there will be huge electric fields floating around.
electromagnetic field pulses which PCs & other equipment are designed to
withstand 3V/m - 10V/m.
EMP field strength 200kV/m.
Ask him for some more details on his 'experiments' with particular details
on voltages and field strengths. Also how far away from you is he, and how
do the power cables run between you?
btw, you do realise that the locals around Castle Frankenstein weren't up
in arms about the murdered young girls, they were complaining about the
interference on Channel 4 ;-)
We have decidedly non-perfect power as we're in a rural location,
the lights do flicker occasionally when heavy loads elsewhere locally
connect and disconnect. None of our PCs is affected by these visible
flickers and we have five or so of them (PCs that is). I've even had
the screen visibly shrink and expand with a voltage fluctuation but the
PC kept going quite happily.
I.e. PCs are mostly quite resistant to voltage fluctuations, if
they're not then the power supplies are distinctly marginal.
yes but some componants are susceptable to spikes and that causes odd
behaviours. we had something similar which turned out to be a damged
network card. made the machine do allsorts of odd inexplicable things.
firstname.lastname@example.org (Lurch) wrote in message
Computer PSUs contain multistage filters and surge suppression. It
takes a fair bit to kill one.
More likely the lights would flash.
On the contrary, PC PSUs are designed to outride wide mains V swings
2 computers going faulty near the same time is not a good reason to
suspect the mains supply. If you go to your poco you'll be doing so
without good grounds. The prime suspect is the faulty items, the
If you want to check the PSU you can meter and scope the PSU lines,
but I would ask for advice in comp.hardware first.
The most likely time for a PC to crash/lockup is when it has just been
switched on from cold. The socketed components move about in their
sockets as they expand, producing brief signal interruptions which
cause the crashes.
The Switch Mode PSU's in PC's can cope with a range of mains voltages
and are able to span a short interruption of supply, so if you are not
noticing lights dimming this is unlikely to be the problem.
Another possibility is that there are some poor and intermittent
connections on just the circuit which supplies your PC's.
Turn your PC's on and allow them to warm up for 30mins, then see if
they crash. If they do, it might be worth looking at buying an
Uninterruptable Power Supply (UPS), or adding surge
We are right in thinking, are we not, that you've tried them in
different locations in the house ... I mean, like, it couldn't be the
socket/ring circuit segment which is dodgy; or even your feet kicking
I've not physically moved 'em, but have run an extension cable from a
downstairs socket upstairs to see if that helped with either PC (it didn't).
I also considered thermal expansion, as normally if my original PC is on for
5 minutes, it'll survive until when I switch it off (Hence the reason I
thought a new mobo was in order as it was doing it with all cards removed).
The thing that's got me worried though it with the other PC doing the same
thing / a similar thing (which may actually be coincidence). Could our
server (used as a firewall) be sending spikes down the network connection
and causing our other PC's problems?
I used to be an avid reader of Everyday Electronics and I remember an
article from a contributor who had odd electrical problems with an old TV.
He connected an oscilloscope to his mains (properly filtered) and monitored
it, and noticed some large spikes at intervals.
I also suspected power tool useage somewhere nearby (a lot of sanding of
floors seems to be done in this area), but I thought it unlikely they'd be
using the equipment at 11:00pm.
I reckon I've changed about 5 or so power supplies for this sort of
thing in the last year or so on various PC's I'm lumbered with. Very
poor quality PC power units, but at 19.99 each in the shops don't
suppose you can expect much....
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