Re: Computer turns on and then just dies

On Mon, 25 Nov 2024 17:33:05 -0500, Paul 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.

That's disappointing, sort of. But I do get to play with the paste.
 
> It's more likely a capacitor is leaking near the CPU socket,
> if the board won't start.

Well then it's removing the hard drives and dump the tower at a recycle
point! If I'll bring it to a computer repair store they will charge me
an arm and a leg.
 
> 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.

I'm learning new things here. It's my brother who knows electricity; I'm
100% sure he's got the equipment to measure.

I checked the PSU that I hopefully can use:

AOpen
Model no: Z400-08FC (400W peak)
 
> 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.

OK, tnx. Does this also fit in the fact that I sometimes get to the BIOS
(however briefly it is) ?
 
> 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.

Will do when you confirm I can use the other PSU. It's ATX, so I'm
guessing yes?

-- 
s|b