Computer won't start

On Tue, 06 Mar 2012 18:36:37 -0800, Loren Pechtel
wrote:

On Mon, 05 Mar 2012 10:15:08 -0500, Metspitzer
wrote:

I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?

My vote: You have a bad power supply. Note that in this case a power
supply tester will *NOT* show the problem.

Considering I don't have a power supply tester that is not really bad
news. I do have another power supply and I intend to give that a try
very soon. All I lack is motivation.

Thanks

What I think is going on here is the power supply can't deliver enough
juice anymore to cover the starting surge. The voltage doesn't
stabilize in time and the deadman circuit kills it. It has no problem
delivering enough for the tester, though.

To test this: Shed every watt you possibly can and try it. Unplug
the power connectors from the drives and any USB devices, if that's
not enough unplug any cards it's possible to POST without.

Alternately, if you have a supply lying around, swap it and see what
happens.

On Tue, 06 Mar 2012 21:51:56 -0500, Metspitzer
wrote:

On Tue, 06 Mar 2012 18:36:37 -0800, Loren Pechtel
wrote:

On Mon, 05 Mar 2012 10:15:08 -0500, Metspitzer
wrote:

I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?

My vote: You have a bad power supply. Note that in this case a power
supply tester will *NOT* show the problem.

Considering I don't have a power supply tester that is not really bad
news. I do have another power supply and I intend to give that a try
very soon. All I lack is motivation.

Thanks

The power supply I plan on using is in a machine that has just lost
it's hard drive for the second time.

What I think is going on here is the power supply can't deliver enough
juice anymore to cover the starting surge. The voltage doesn't
stabilize in time and the deadman circuit kills it. It has no problem
delivering enough for the tester, though.

To test this: Shed every watt you possibly can and try it. Unplug
the power connectors from the drives and any USB devices, if that's
not enough unplug any cards it's possible to POST without.

Alternately, if you have a supply lying around, swap it and see what
happens.

On Tue, 06 Mar 2012 21:53:48 -0500, Metspitzer
put finger to keyboard and composed:

The power supply I plan on using is in a machine that has just lost
it's hard drive for the second time.

The failure modes of the hard drives will give us a clue as to whether
the failures were related to the PSU.

BTW, you can purchase a multimeter for US$5, eg ...

Cen-Tech 90899 7 Function Digital Multimeter:
http://www.harborfreight.com/7-funct...ter-90899.html

If there is a short circuit on one of the devices, eg HDD, then
powering it up again and again will only risk doing more serious
damage to it. Take some resistance measurements first.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Thu, 08 Mar 2012 08:36:26 +1100, Franc Zabkar
wrote:

On Tue, 06 Mar 2012 21:53:48 -0500, Metspitzer
put finger to keyboard and composed:

The power supply I plan on using is in a machine that has just lost
it's hard drive for the second time.

The failure modes of the hard drives will give us a clue as to whether
the failures were related to the PSU.

BTW, you can purchase a multimeter for US$5, eg ...

Cen-Tech 90899 7 Function Digital Multimeter:
http://www.harborfreight.com/7-funct...ter-90899.html

If there is a short circuit on one of the devices, eg HDD, then
powering it up again and again will only risk doing more serious
damage to it. Take some resistance measurements first.

- Franc Zabkar

I did unplug all the hard drives and try again. Nothing. No power
supply fan only a bump on the CPU fan.

As several have suggested, when I get motivated I will try another
power supply.

Thanks

Bump on the CPU fan would indicate that the power supply is doing a
crowbar shutdown because something is drawing too much current.

This can be on the motherboard from shorted capacitor(s), internal
shorts on CPU or graphics chip, or shorted line drivers on the serial
lines. Or just a failure in the power supply itself or on an optical
drive.

Generally have found that failures protected by crowbar have left the
hard drives unaffected.

YMMV

On Mon, 05 Mar 2012 10:15:08 -0500, Metspitzer
wrote:

I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?

The correct answer was Power Supply. When I changed it with another
power supply, it started.

Every power supply I ever tested (less than a dozen) shows continuity
from hot to neutral. I assume this means the fuse is good. This
power supply shows no continuity from hot to neutral. I have
contacted Antec to see if it is still under warranty, so I don't plan
to open the case. (I think I ordered the PS from Amazon and it seems
that Amazon has lost it's order history)

The thing is, I can't explain how the fan rotated for an instant if
the fuse was bad.

On Mon, 5 Mar 2012 11:01:52 -0500, "SC Tom" wrote:


"Metspitzer" wrote in message ...
I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?

Does the power supply fan start up? If not, that may be your problem; most PS won't come up if the fan doesn't start
first. Or the PS itself may have died. The ready light is just a small part of what it does.

Unplug the AC cord from the back of the computer or from the wall, whichever is easiest. Leave it unplugged for about a
minute, then plug it back in. Does the PC start now?

When you turn it on, does the keyboard light up?

Unplug everything that's not necessary, like printers, external drives, etc. Also unplug any CD drives internally. Did
that help?

Is this a newer machine, maybe still under warranty? Have you ever had a problem before? If it's an older machine, have
you ever changed the CMOS battery? If not, you might try a new battery, although that's probably not it.

When I read this message I was at a no posting on Usenet machine.

I have the computer on the kitchen table so most of your suggestions
are not practical to try at the moment. Also, the machine is using a
very large CRT monitor so getting the two back together is a pain.

Thanks for your suggestions.

On 05 Mar 2012 18:36:07 GMT, Sjouke Burry s@b wrote:

Metspitzer wrote in
:

I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?


Had about the same a few weeks ago.

Turned out to be a failed power button.
That was a rather cheap repair, 59 Euros,
including a new DVD ram unit.

You must be living right. No way I expect my solution to be that
simple.

On Tue, 06 Mar 2012 08:29:21 +1100, Franc Zabkar
wrote:

On Mon, 05 Mar 2012 10:15:08 -0500, Metspitzer
put finger to keyboard and composed:

I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?

I suspect there may be a short circuit on one of the supply rails. Use
a multimeter to measure the resistances on the +5V and +12V supplies.

I haven't tried this yet, but I did start the computer with the other
power supply with no hard drives.

On Mon, 05 Mar 2012 17:30:58 -0500, Allen Drake
wrote:

On Mon, 05 Mar 2012 10:15:08 -0500, Metspitzer
wrote:

I have an XP machine that was working fine last night when I shut it
down. It would not start this morning. I pulled the side off. The
mobo ready light burns. I unplugged the power supply from both mobo
connection and re seated them. When I push the power button, the CPU
fan rotates for just an instant.

I hear no hard drive. I have seated the memory and checked all the
mobo to case connections. There is no mobo beep.

What can I check next?

Everyone that owns a computer should own a PSU tester. Very cheap and
save much time and trouble. PSUs are the most common component
failure.

It might be a good time to get one.
Thanks