computer shuts down

My son has a HP Pavillion 700 that quit working. Said was making noise, then
quit. Power supply is bad, so I replaced. Now when powering up, will turn
off after a few seconds, 10, 15.. No matter what option I choose on screen,
safe mode, start normally, restore previous settings, etc, it just shuts
down. Don't really know where to go from here, am asking for suggestions.
Thanks

--
Jan Alter
bearpuf@verizon.net
or
jalter@phila.k12.pa.us
"Bob" <jdf32@yahoo.com> wrote in message
news:HfI5h.34232$39.9566@southeast.rr.com...
> My son has a HP Pavillion 700 that quit working. Said was making noise,
> then quit. Power supply is bad, so I replaced. Now when powering up, will
> turn off after a few seconds, 10, 15.. No matter what option I choose on
> screen, safe mode, start normally, restore previous settings, etc, it just
> shuts down. Don't really know where to go from here, am asking for
> suggestions. Thanks
>

"Bob" <jdf32@yahoo.com> wrote in message
news:HfI5h.34232$39.9566@southeast.rr.com...
> My son has a HP Pavillion 700 that quit working. Said was making noise,
> then quit. Power supply is bad, so I replaced. Now when powering up, will
> turn off after a few seconds, 10, 15.. No matter what option I choose on
> screen, safe mode, start normally, restore previous settings, etc, it just
> shuts down. Don't really know where to go from here, am asking for
> suggestions. Thanks
>
Try resetting the cmos. use the cmos jumper on the mb or pull the battery
out for 10 minutes if you aren't sure which jumper to use. Don't forget to
unplug the computer from the AC first before doing this. Another possibility
is it sounding as if the cpu fan is not registering to the cmos that it's
there.

--
Jan Alter
bearpuf@verizon.net
or
jalter@phila.k12.pa.us

Bob wrote:
> My son has a HP Pavillion 700 that quit working. Said was making noise, then
> quit. Power supply is bad, so I replaced. Now when powering up, will turn
> off after a few seconds, 10, 15.. No matter what option I choose on screen,
> safe mode, start normally, restore previous settings, etc, it just shuts
> down. Don't really know where to go from here, am asking for suggestions.
> Thanks

That sounds familiar. Open the box up, and inspect the board for any
since of obvious failure, including blown or vented capacitors.

http://www.answers.com/topic/capacitor-plague

Bob wrote:
> My son has a HP Pavillion 700 that quit working. Said was making noise, then
> quit. Power supply is bad, so I replaced. Now when powering up, will turn
> off after a few seconds, 10, 15.. No matter what option I choose on screen,
> safe mode, start normally, restore previous settings, etc, it just shuts
> down. Don't really know where to go from here, am asking for suggestions.
> Thanks
>
>

If it just shuts down, it could be a loose CPU heatsink. If there is
sufficient time, start the machine, and enter the BIOS. See if the
BIOS has a hardware monitor screen. Some motherboards can measure
temperature and fan speed, and there is a display in the BIOS to
show the values.

Alternately, you can open the case, remove the heatsink (depending
on what kind of clips or levers it uses). The heatsink would likely
have the original thermal compound on it. You can clean off whatever
is on there, and get a tube of thermal paste at a local computer
store. You want something that won't quickly leave the scene.
And the only thing I personally would not select as a compound,
is a zinc paste (white colored material, with a wattery component
to it, that can separate from the paste). A thin layer of thermal
compound is best, as its purpose is to displace any air in the gap
between CPU and heatsink.

Don't disassemble the CPU, until you have the paste product ready
to go. The preapplied material on the heatsink, scratches up easily,
so you want your replacement paste ready, for reassembly.

Even before removing the heatsink, you can view the heatsink/fan
assembly and inspect for good fan rotation and no dust bunnies.
If the fan isn't spinning, that could do it too. Check that the
fan is plugged into the motherboard header. Fan headers are keyed
with a tab, to help you get the connector on the right way. (You
shouldn't have to force it - if the force is high, check that the
tab is the right way).

Modern P4 and Athlon64 systems have THERMTRIP, which is a logic
signal from the processor, to the power logic. If the temp goes
too high, THERMTRIP will cause the power supply to shut off. The
BIOS or OS don't get a say in the matter, so there will be no
announcement that it is going off. It just goes off.

Paul

Bob wrote:
> My son has a HP Pavillion 700 that quit working. Said was making noise, then
> quit. Power supply is bad, so I replaced. Now when powering up, will turn
> off after a few seconds, 10, 15.. No matter what option I choose on screen,
> safe mode, start normally, restore previous settings, etc, it just shuts
> down. Don't really know where to go from here, am asking for suggestions.
> Thanks

My first step would be to rule out software versus hardware.

Put a blank floppy into the drive and boot off it. The boot will fail.
But the hardware will all be powered up, and no drivers or software
will be loading.

See how long it stays on. If it stays on for 5 minutes, I would begin
to suspect software.

You could also rule out a couple of other things if you're prepared to
make a boot floppy. Download memtestX86. Load that from a boot floppy.
See if you can run it. If you can, let it run overnight, and check for
errors.

These steps won't necessarily tell you what the problem is, but they
may well indicate what it is *not*.

Cheers,

BD

After posting this yesterday, I did some more poking around on motherboard.
Indeed, as Paul has posted, there is a loose clip on the heatsink. Has 2
clips, and one was completely off. Trouble is, one side of the base where
heatsink sets, and where it clips, is broken, nothing to clip it to. Turned
computer on side and broken, very small black piece fell out. I see no way
of fixing, but welcome any suggestions. Thanks for previous replys.

"Bob" <jdf32@yahoo.com> wrote in message
news:4s06h.22049$nG1.17106@tornado.southeast.rr.com...
> After posting this yesterday, I did some more poking around on
> motherboard. Indeed, as Paul has posted, there is a loose clip on the
> heatsink. Has 2 clips, and one was completely off. Trouble is, one side of
> the base where heatsink sets, and where it clips, is broken, nothing to
> clip it to. Turned computer on side and broken, very small black piece
> fell out. I see no way of fixing, but welcome any suggestions. Thanks for
> previous replys.

I haven't seen your other post, but you might be able to find a heatsink
that uses the holes in your mainboard located around your CPU socket.

On Mon, 13 Nov 2006 15:47:12 GMT, "Bob" <jdf32@yahoo.com>
wrote:

>After posting this yesterday, I did some more poking around on motherboard.
>Indeed, as Paul has posted, there is a loose clip on the heatsink. Has 2
>clips, and one was completely off. Trouble is, one side of the base where
>heatsink sets, and where it clips, is broken, nothing to clip it to. Turned
>computer on side and broken, very small black piece fell out. I see no way
>of fixing, but welcome any suggestions. Thanks for previous replys.
>


Is it a socket A/ Athlon or Duron based system?
If so, thee should be more than one lug on each side of the
socket, you merely need a heatsink with the three point clip
like this,

http://us.st11.yimg.com/us.st.yimg....e_1922_58305995
http://www.svcompucycle.com/fa782n.html

This is an example only, the ideal heatsink would have a
copper base though if your CPU is low enough speed it might
not produce enough heat that it'd matter.

Processor is pentium 4, 2.53 ghz, not to old computer. I have not taken
motherboard out to inspect heatsink closely. Thanks for reply.