timO' wrote:

On Oct 4, 2:45 am, Paul wrote:

timO' wrote:

for no apparent reason pc just shuts off by itself . I have a Zalman
fan. what should my readings be? what should my settings be? front
case fan rear case fan, cpu fan,ps fan all spinning.
.
I had the side cover off for a while but put it back after first
shutdown.
the case has a temp probe which i put on the heartsink on the mobo
chipset has always read about 36C as is doing so now tooi, though may
have been higher with cover off. it isn't even summer anymore.
thought i heard a vibration ao that's why i hade cover off to
investigate. seems to be one of the hard drives, but not severe and no
apparent performance problems, right now mb says 100F cpu 120F
please help

Possible reasons for shutdown, would be a CPU overheat problem, or
the PSU shutdown because it detected a problem.

CPU overheat is set at two levels. The first temperature is the
"throttle" temperature, and the processor will slow its computing
rate, to try to control the temperature.

If that fails to work, and the processor gets hot enough, the
THERMTRIP temperature is reached. At that point, as long as the
THERMTRIP signal is wired to the motherboard logic, the motherboard
should turn off the PSU.

Throttle is around 65C, and THERMTRIP is at least 20C more than
that. On some of the older P4 processors, THERMTRIP was up around
135C. You can get exact numbers from an Intel processor datasheet.

120F is about 49C, and no reason for the processor to get excited.

So I suppose that leaves a PSU problem. Is the air coming from the
PSU very hot ? Hotter than you would normally expect ? Have there
been any startup issues with the PSU, or other warning signs ?
Any funny smells from the PSU ? Have you visually inspected the
capacitors on the motherboard, for leaking or bulging tops ? Maybe
a problem with the motherboard, is causing the PSU to protect
itself.

Paul


system is less than year old has this pc probe app i never use butr it
tells you temps mobo is 122 this morning.
no smells.
like out of no where.
thanks for the feedback


Motherboard temperature should not be significantly greater than ambient.
If it is, then it indicates poor air flow through the chassis. What is the
threshold temperature for the motherboard warning and trip? OTOH, a high
motherboard temperature also indicates that the CPU temperature is also
high since the measuring points are in relatively close proximity to
each other. While CPU throttling would occur at around 65 deg C., this
is a feedback control action and the CPU could well be spiking up to
its maximum temperature at which it will shut down.