Do you have a question? Post it now! No Registration Necessary. Now with pictures!
- Posted on
- Failing power supply? bad MB?
May 23, 2006, 10:16 pm
rate this thread
computer with Windows XP home--purchased in 2001)
When I boot it up, it displays the initial boot-up information, and
even goes into windows. Then maybe 10 seconds later (but this amount
of time varies from boot to boot), I get these issues (all at once):
1) The monitor goes black with a message saying, "No Signal Detected".
2) The light by the power button on the monitor turns amber (instead of
3) The fan on the CPU shuts off
4) The fan going from the inside of the case to the outside (just for
circulation, i guess) shuts off.
5) The CD drive no longer opens up.
6) Ctrl+Alt+Del, Alt, u, r (which, in a normal xp home system would
reboot a computer) does not reboot the computer.
I initially thought that the whole thing had shut off, but...
7) I can still hear the power supply running, and
8) I still hear something that sounds like a fan, but I can't locate
it. (I think it's the hard drive, because once, i unplugged the power
to it, and then booted, and the sound was missing. But I didn't know a
hard drive sounded... like a fan.)
9) I still have to hold the power button down for about 5-6 seconds
before everything turns off all the way.
Once I've turned the thing all the way off, I can push the power button
again to boot, and it does the same thing once it gets into windows.
It seems to only fail after it's gotten all the way into Windows XP.
(Once, I booted into safe mode, and it didn't show these symptoms. I
got bored of being in Safe Mode after a couple of minutes, and rebooted
into safe mode with networking support--this time, it died on me
I'm pretty sure it's not a software issue because I reformatted and
reinstalled windows after i first noticed the issue. It reinstalled
without any problems, and I even got the system customized a bit before
it went on the fritz again.
So... Could it be a power supply issue? If it is, why would it work
sometimes and not always? Is there a certain point within running
windows where the power supply is in more demand, and if it's dying, it
can't produce the power, so things shut off?
Could it be a mother board issue? But how could it boot at all if it
I suspect it's the power supply... I might even be able to blame it on
my cat, who, a couple of weeks ago, thought it would be funny to turn
my computers off by playing on the floor under my desk and stepping on
the on/off switch of my surge protector--a couple of times--in the same
day. I can't remember exactly, but I'm pretty sure that the problems
didn't appear until after that day.
Clearly, something is only "mostly dead", not all-dead, because it
always starts up again the next time.
I might try using the power supply from my second computer to power the
broken one, but I probably won't have time tonight.
Any wisdom on the subject would be greatly appreciated!
Re: Failing power supply? bad MB?
questions. Two simple tasks to isolate the problem. Is it software or
hardware?. Given what was posted, you currently have no idea. Break
the problem down into parts and analyze those parts separately.
Responsible computer manufacturers provide comprehensive hardware
diagnostics for free. That is software that does not use Windows - to
boot and test hardware. I have forgotten which key is pressed to
select diagnostics. For example press DEL, F2 F10 and F12 repeatedly
until diagnostics can be selected. Hopefully you did not destroy those
diagnostics when you tried to shotgun - reload windows without first
learning reasons for the problem.
BTW, system may have detected the problem long ago and held that
information in the system (event) log. By reloading windows, that
historical information is deleted.
If system never even gets out of BIOS execution and therefore cannot
load comprehensive hardware diagnostics, then a meter will report in
but two minutes where the problem lies. You think power supply is
working because you don't have numbers. Without those numbers, you can
only shotgun - keep replacing things until something appears to work.
Before and when power switch is presses, the 3.5 digit multimeter
monitors voltage on purple, green, and gray wire. Purple must always
have 4.87 volts or higher at all times. Green must go from greater
than 2 volts to less than 0.8 volts when power switch is pressed. Gray
wire must rise to greater than 2.4 volts within two seconds after power
switch is pressed.
Next monitor red, orange, and yellow wires for values that exceed
3.22, 4.87, and 11.7 volts in less than 2 seconds after power switch is
pressed. If any one voltage here does not perform, the machine will
Most important, post these numbers. Not only do they report a
GO-NOGO suggestion to you. They also tell your assistance further
information about your problem.
Swapping power supplies - shotgunning - can cause additional damage
or mask the problem by making a temporary correction. Always best to
first get the numbers long before swapping - shotgunning - anything.
Re: Failing power supply? bad MB?
evening. (Unfortunately, before I saw your post, though.)
--"Is it software or hardware?"
I think it's definately hardware. I just disconnected the hard drive,
and inserted a Knoppix cd into the cd-rom. Knoppix booted fine, but
after a while (when I was trying to go play a game), it died again
(same exact (as far as I can tell) symptoms as mentioned above). So
it's not the hard drive, and it's not Windows.
Its not the power supply either. I used the power supply from my other
computer and plugged it in to the bad computer--same symptoms again.
Windows boots fine, but then the computer dies sometime after it has
--"press DEL, F2 F10 and F12 repeatedly until diagnostics can be
Do you mean that the diagnostics are somewhere within the bios? Or do
you mean the "Windows Advanced Options Menu"? (which lets you boot in
safe mode, s.m. with networking, enable boot logging, last known good
configuration, debugging mode, etc.) Or is it some other utility?
--"BTW, system may have detected the problem long ago and held that
information in the system (event) log"
How do I get to the system event log? Is it somewhere in the "Manage"
part of right-clicking on My Computer? (But regardless of where it is,
I might not be able to get to it before it dies on me again...)
I always thought multimeters were pretty interesting, but I never
thought I'd need one, so I've never bought one. :( (But like I said a
bit ago, I don't think it's the power supply, since I swapped it out,
and got the same result. (and luckilly didn't fry anything in the
meantime--to my knowledge...))
I wish I had something more conclusive to report. I can only say that
I don't think it's the power supply, hard drive, or OS/software.
It could still be the motherboard. :( What about the processor? or
the memory? (Maybe I'll try swapping the memory out, next.)
Is it possible for either the motherboard, processor, or the memory to
have problems, and still get an operating system to boot before the
problems become visible?
I have a Pentium 4 on this computer, but a Celeron in the broken one.
I probably can't switch them, then, can I?
I doubt it's a problem with the monitor because the cd-rom, OS, and
fans on the processor and in the back of the case don't work either.
But I can't swap the monitor with another, so I can't be sure. (This
monitor is digital, and the one to the spastic computer is analog--and
I don't have the connector for the opposite monitors on either of my
Ok, so now that I get to the end of my post, I think I might know
what's really going on...
I noticed tonight that some of the capacitors look like they have...
leaked out of the top of them or something. About 9 of them--all of
them are the same shape, size, and color (and all of the capacitors of
that shape/size/color). I don't know how long they've been like that,
but it looks like it's been a while. (But I thought it unwise to touch
them, so... that's about all I know about them.) I can't immagine that
it happened only within the last two weeks, by the look of it, but how
should I really know? I never even knew that they could do such a
thing until tonight. So maybe that's what they look like even right
after it happens...
Do you think that these bad capacitors could be causing all these
Re: Failing power supply? bad MB?
Power supply 'system' is more than just the one component called a
power supply. Just another reason why 2 minutes with the meter reports
so much so quickly.
Comprehensive hardware diagnostics are loaded by BIOS - long before
Windows starts executing and giving Windows options such as safe mode
and booting without networking. If the diagnostic partition was
destroyed by reloading windows, then go to HP web site to find
diagnostics (named something like 'Diagnostic Doctor').
If capacitors are bulging or leaking, that is failure whether some
other failure exists or not. Meter may have detected this problem long
before computer started failing. Meanwhile, recored voltage,
temperature, and microfarads for each to order and replace them - a
siimple solution using a soldering iron. Otherwise, you must buy a
whole new motherboard, maybe new processor, etc. This capacitor
problem was found in all manufacturer computers due to electrolytic
counterfeiting in early 2000s. Dell has to put aside $millions to
replace defective motherboards. Even power supply controller would
become unstable due to defective caps.
Bad caps means power supply voltages vary too much. It is consistent
with your symptoms.
Meanwhile System (event) logs are found in Control Panel or go to
Windows Help for assistance.