Computer freezes. PSU?

[Daniel Vallstrom]

My computer freezes seemingly randomly. It can occur at start when the
computer is cold, and after 5 hours running. It has become more
frequent lately. Sometimes the computer won't even power up properly
and go into some limbo (before boot). Lately the computer always
freezes when I do something graphic intensive like starting a game.

I'm guessing that it is the power supply that is acting up. Does that
seem the most likely? Or is it the motherboard? Or even the CPU?
Disconnecting the CD-ROM and a couple of fans don't seem to help.

The computer is a few years old and has been used a lot. Parts I'm
using:
Nexus NX-4090 ATX 400W PSU
Asus A7N8X-E Deluxe motherboard
Athlon XP 2600+
Geforce 6600 AGP

 

[kony]

My computer freezes seemingly randomly. It can occur at start when the
computer is cold, and after 5 hours running. It has become more
frequent lately. Sometimes the computer won't even power up properly
and go into some limbo (before boot). Lately the computer always
freezes when I do something graphic intensive like starting a game.

I'm guessing that it is the power supply that is acting up. Does that
seem the most likely? Or is it the motherboard? Or even the CPU?
Disconnecting the CD-ROM and a couple of fans don't seem to help.

The computer is a few years old and has been used a lot. Parts I'm
using:
Nexus NX-4090 ATX 400W PSU
Asus A7N8X-E Deluxe motherboard
Athlon XP 2600+
Geforce 6600 AGP

Examine the motherboard capacitors but I suspect the PSU
too, and it is not so well mated with your system as it
seems to only have a combined 3V+5V rating of 150W, while
your motherboard uses 5V rail for the CPU power circuit so a
better matched replacement should have 200W or more combined
3V+5V rating.

Probably between 1-4 failed capacitors in the PSU. You
could unplug the PSU from AC for a few minutes then open,
inspect it (assuming no warranty remains on it) Eyeball
those caps and check temps, voltages with a multimeter. If
it only happened hot I would add failed video card fan to
the list but it should not be a factor when the system is
cold, first turned on.

Disconnecting a couple fans and a CDROM drive aren't enough
of a change in load to matter, if that was the goal.
Substituting a low powered video card (some old PCI card for
example) or (temporarily) underclocking the CPU as much as
possible (you might just try lowering the FSB to 100 or 133,
whatever the lowest it supports) would be a more significant
power reduction..

 

[Daniel Vallstrom]

Examine the motherboard capacitors but I suspect the PSU
too, and it is not so well mated with your system as it
seems to only have a combined 3V+5V rating of 150W, while
your motherboard uses 5V rail for the CPU power circuit so a
better matched replacement should have 200W or more combined
3V+5V rating.

Probably between 1-4 failed capacitors in the PSU. You
could unplug the PSU from AC for a few minutes then open,
inspect it (assuming no warranty remains on it) Eyeball
those caps and check temps, voltages with a multimeter. If
it only happened hot I would add failed video card fan to
the list but it should not be a factor when the system is
cold, first turned on.

I looked at the capacitors on the motherboard and in the PSU but
couldn't find any faulty ones. Moreover, I tested with a new 430W
PSU with 200W for 3V+5V but I still had the same problems.

Does that indicate that it's the motherboard that is causing the
problems?

Disconnecting a couple fans and a CDROM drive aren't enough
of a change in load to matter, if that was the goal.
Substituting a low powered video card (some old PCI card for
example) or (temporarily) underclocking the CPU as much as
possible (you might just try lowering the FSB to 100 or 133,
whatever the lowest it supports) would be a more significant
power reduction..

I set the FSB to 100 but that didn't help either.

 

[Daniel Vallstrom]

I looked at the capacitors on the motherboard and in the PSU but
couldn't find any faulty ones. Moreover, I tested with a new 430W
PSU with 200W for 3V+5V but I still had the same problems.

Does that indicate that it's the motherboard that is causing the
problems?

I just now tested with an old Geforce 2 graphic card and so far there
has been no problem. Could it be my Geforce 6600 that is causing
all the problems?

 

[kony]

I just now tested with an old Geforce 2 graphic card and so far there
has been no problem. Could it be my Geforce 6600 that is causing
all the problems?

Yes it's possible, and likely. Certain types of motherboard
failures might make the video card power faulty but if your
6600 has the external power connector that becomes even less
likely. Is the 6600 passively cooled or if fanned, does the
fan work? It could damage the core if it had failed, or if
passively cooled that can heat stress the card over time if
the system didn't have pretty good airflow past the card - I
usually like to leave the adjacent PCI slot empty and that
slot's case bracket cover off for more passive airflow past
such cards.

 

[Daniel Vallstrom]

On 11 May 2007 10:14:51 -0700, Daniel Vallstrom

Yes it's possible, and likely. Certain types of motherboard
failures might make the video card power faulty but if your
6600 has the external power connector that becomes even less
likely. Is the 6600 passively cooled or if fanned, does the
fan work? It could damage the core if it had failed, or if
passively cooled that can heat stress the card over time if
the system didn't have pretty good airflow past the card - I
usually like to leave the adjacent PCI slot empty and that
slot's case bracket cover off for more passive airflow past
such cards.

My 6600 does have an external power connector and is passively
cooled. I'm pretty sure now that it's the 6600 that has been
damaged since everything has been working just fine with the
geforce 2 for a long time. I actually do have the next door slot
open too but overall the cooling was apparently insufficient.