T
Tony Cooper
Hi,
I wonder if someone can help...
My system will sometimes switch itself off completely shortly
after switching it on. On the four occasions it has happened it
switched off after about 1/2 an hour, once it did it twice in quick
succession. I switch back on and it seems to run fine.
I built the system myself this July. Spec:
Asus P4C800 Delux (2.8 HpThrd Intel) (BIOS ver 1006.005)
512MB memory
520W Top Power PSU (TOP-520P4)
Gainward Nvidia FX5600
Lian Li PC-60 case.
Win XP
The PSU has a selector switch on the back with A, M, and L
marked on it (for Auto, Medium and Low). It auto-adjusts the fan speed
to keep noise to a minimum.
When it switches off it does so without warning, just as if
someone pulled the plug apart from the standby power is still on (can
see green LED on MB glowing). But everything else is dead. On
switching on it starts up as if nothing has happened.
I checked the temp of the MB and CPU, both physically and
using the ASUS probe utility. No signs of overheating (the opposite in
fact). Voltage seems fairly steady (vcore normally 1.556 sometimes
1.48, +3.3 is spot on always, 5v ~4.9 and 12v ~11.7)
Also read on other groups postings about tracks being shorted
out on the P4C800 Dlx by squashed solder under the heatsink bracket.
Presumably this would cause intermittent lockups and crashes with POST
failing - I have had none of these.
My questions are:
- What causes an ATX PSU to power up or shutdown? Does it detect
loading from the MB or is there a dedicated signal line that
explicitly tells it to switch on or off?
- If loading triggered, could a fault on the MB or expansion card
cause this problem?
- Also it only has ever happened between 7:30 and 8 pm in the evening.
The last time it did it, about a month after the last incident, I
noticed that the vcore voltage was fluctuating slightly (I now know
that usually they are all rock steady apart from the 12v one which
wavers very slightly). After a time it started to settle down. It
could be an overly sensitive PSU reacting to a fluctuating mains. The
other times it has done it my old computer has been on and that didn't
bat an eye lid (Pentium 90 with a pre-ATX power supply). Does this
make sense and if so what can I do about it? I have surge protectors
but they're no good in situations of low power.
- Has anyone had experience with TopPower power supplies? Are they
considered a reliable make, if not then what is considered good? Is
there a chance that switching it onto manual may make it more reliable
(dumbly letting fluctuating voltage through rather than possibly
detecting a wobbly mains and switching off just in case).
- After a switchoff Win XP doesn't seem to do any file system
checking, is it journalled? It always seems ok when I manually check
it (either a scheduled check using chkdsk or the GUI one).
Any help would be greatly appreciated.
MTIA
Tony.
If at first you don't succeed... Delegate.
Pay a visit to my home page at:
http://www.coosoft.plus.com/
I wonder if someone can help...
My system will sometimes switch itself off completely shortly
after switching it on. On the four occasions it has happened it
switched off after about 1/2 an hour, once it did it twice in quick
succession. I switch back on and it seems to run fine.
I built the system myself this July. Spec:
Asus P4C800 Delux (2.8 HpThrd Intel) (BIOS ver 1006.005)
512MB memory
520W Top Power PSU (TOP-520P4)
Gainward Nvidia FX5600
Lian Li PC-60 case.
Win XP
The PSU has a selector switch on the back with A, M, and L
marked on it (for Auto, Medium and Low). It auto-adjusts the fan speed
to keep noise to a minimum.
When it switches off it does so without warning, just as if
someone pulled the plug apart from the standby power is still on (can
see green LED on MB glowing). But everything else is dead. On
switching on it starts up as if nothing has happened.
I checked the temp of the MB and CPU, both physically and
using the ASUS probe utility. No signs of overheating (the opposite in
fact). Voltage seems fairly steady (vcore normally 1.556 sometimes
1.48, +3.3 is spot on always, 5v ~4.9 and 12v ~11.7)
Also read on other groups postings about tracks being shorted
out on the P4C800 Dlx by squashed solder under the heatsink bracket.
Presumably this would cause intermittent lockups and crashes with POST
failing - I have had none of these.
My questions are:
- What causes an ATX PSU to power up or shutdown? Does it detect
loading from the MB or is there a dedicated signal line that
explicitly tells it to switch on or off?
- If loading triggered, could a fault on the MB or expansion card
cause this problem?
- Also it only has ever happened between 7:30 and 8 pm in the evening.
The last time it did it, about a month after the last incident, I
noticed that the vcore voltage was fluctuating slightly (I now know
that usually they are all rock steady apart from the 12v one which
wavers very slightly). After a time it started to settle down. It
could be an overly sensitive PSU reacting to a fluctuating mains. The
other times it has done it my old computer has been on and that didn't
bat an eye lid (Pentium 90 with a pre-ATX power supply). Does this
make sense and if so what can I do about it? I have surge protectors
but they're no good in situations of low power.
- Has anyone had experience with TopPower power supplies? Are they
considered a reliable make, if not then what is considered good? Is
there a chance that switching it onto manual may make it more reliable
(dumbly letting fluctuating voltage through rather than possibly
detecting a wobbly mains and switching off just in case).
- After a switchoff Win XP doesn't seem to do any file system
checking, is it journalled? It always seems ok when I manually check
it (either a scheduled check using chkdsk or the GUI one).
Any help would be greatly appreciated.
MTIA
Tony.
If at first you don't succeed... Delegate.
Pay a visit to my home page at:
http://www.coosoft.plus.com/