Re: Computer turns on and then just dies

On Mon, 11/25/2024 8:58 AM, s|b wrote:

> I'm making a note of that. I bought the PC in 2012, so there's a good
> chance it's the CPU and not the PSU that causes the shutdown?
>  

Unlikely.

If a heatsink falls off the CPU, the temperature shoots up to 200C,
the thermal protection does not engage immediately, that
could damage a CPU.

But really, with the heatsink fastened to the top, there is
thermal inertia (mass) and the temperature does not shoot up
quite as rapidly.

It's more likely a capacitor is leaking near the CPU socket,
if the board won't start.

But your case, your initial symptoms were an overloaded +5VSB.
I suggested measuring the current, as one way to ascertain
if there is a specific problem with the combination of
components. If something is shorted on the motherboard,
then the problem (box shuts off), may still be present
with your spare supply installed. You would put in the
spare supply. The LED would be lit for a minute or two,
then go off on its own. That could be an overload of +5VSB
for example.

Modern motherboards (yours is modern enough), have THERMTRIP.
If the CPU goes over 100C to 120C or so, THERMTRIP causes
PSON# to be deasserted and the PC fans stop spinning, and
3.3V/5V/12V are then powered off. You can have a shutdown
due to a thermal issue. The Asus LED remains lit when that happens
(a THERMTRIP).

But the thing is, you told us that the Asus LED, which
monitors +5VSB, that went OFF. That's an indication of
a power supply problem, not a THERMTRIP. THERMTRIP will
not turn that LED off.

The LED then, is key to determining whether you have
a "NEW" or "DIFFERENT" problem than the first one reported.

1) Swap out power supply. Put in known-good supply.
2) Record symptoms again. Does PC shut off as before ?
   Does the Asus LED stay lit after the erroneous shutdown ?

Report back.

   Paul