Power Supply?

  • Thread starter Thread starter Andy
  • Start date Start date
A

Andy

To All Cognoscenti, Greetings!

My computer keeps shutting down as if the plug was yanked from the wall. The
power cannot be turned back on for a few minutes, after which it can be
powered up again. This has happened three times so far, with about a week or
two of normal operation in between. The electrical outlet is fine. Am I
right in suspecting an overloaded power supply? Could there be any other
cause?

Thanks for your suggestions in advance.

Andy
 
Andy said:
To All Cognoscenti, Greetings!

My computer keeps shutting down as if the plug was yanked from the wall. The
power cannot be turned back on for a few minutes, after which it can be
powered up again. This has happened three times so far, with about a week or
two of normal operation in between. The electrical outlet is fine. Am I
right in suspecting an overloaded power supply? Could there be any other
cause?

Thanks for your suggestions in advance.

Andy
Click to expand...

Inadequate airflow is a possibility. Clogged filters, dirt-encrusted
fan blades or heat sinks, something blocking air inlets or outlets,
some fan not spinning, ...
 
Previously Andy said:
To All Cognoscenti, Greetings!
Click to expand...
My computer keeps shutting down as if the plug was yanked from the wall. The
power cannot be turned back on for a few minutes, after which it can be
powered up again. This has happened three times so far, with about a week or
two of normal operation in between. The electrical outlet is fine. Am I
right in suspecting an overloaded power supply? Could there be any other
cause?
Click to expand...
Thanks for your suggestions in advance.
Click to expand...

Might have lost capacity due to ageing resulting in overload. This
happens pretty often and if the load was high but acceptable before
it can become too large after some time.

Arno
 
Would suspect cooling capacity of the power supply itself. Probably
shutting down automatically to protect from overheat, and remains that way
until it cools down enough for a restart. If the power supply is the single
way for heat to leave the PC, then check for impeded air flow into the PC
and into and out of the power supply.

The electrical part of the power supply is not a suspect here, as you would
have problems starting the PC to begin with due to increased starting
current needed.
 
Andy said:
To All Cognoscenti, Greetings!

My computer keeps shutting down as if the plug was yanked from the wall. The
power cannot be turned back on for a few minutes, after which it can be
powered up again. This has happened three times so far, with about a week or
two of normal operation in between. The electrical outlet is fine. Am I
right in suspecting an overloaded power supply? Could there be any other
cause?
Click to expand...

Check the CPU temperature reported by the BIOS after an hours use.

Check the CPU heatsink - on mine you need to use a torch because grey dust
looks much like aluminuim so it's hard to see if the heatsink is blocked
dust. If that's ok consider replacing the power supply.
 
Lil' Dave said:
Would suspect cooling capacity of the power supply itself.
Click to expand...

Very unlikely.
Probably shutting down automatically to protect from overheat,
and remains that way until it cools down enough for a restart.
Click to expand...

Much more likely to be a faulty power supply or motherboard.
If the power supply is the single way for heat to leave the PC, then check
for impeded air flow into the PC and into and out of the power supply.
Click to expand...

You'd normally see problems with the cpu getting too hot first.
The electrical part of the power supply is not a suspect here,
Wrong.

as you would have problems starting the PC to begin
with due to increased starting current needed.
Click to expand...

Wrong. What causes it to shut down and need to minutes
before it can be started again has nothing to do with startup.
 
Andy said:
To All Cognoscenti, Greetings!
Click to expand...
My computer keeps shutting down as if the plug was yanked from the wall. The
power cannot be turned back on for a few minutes, after
which it can be powered up again. This has happened three times so
far, with about a week or two of normal operation in between. The
electrical outlet is fine. Am I right in suspecting an overloaded power
supply?
Click to expand...

It shouldnt need to be off for minutes if it was that,
Could there be any other cause?
Click to expand...

Yes, a faulty power supply.

It can also be a bad motherboard, faulty caps on the motherboard.

Have a look at the usually blue or black plastic covered posts sticking
up vertically from the motherboard, check that the tops are flat and
that there is no visible leak. If you see either, those are the faulty caps.

Its obviously cheaper to try a new power supply than
motherboard if you cant see any visible problem.
 
Inadequate airflow is a possibility.
Click to expand...

Nope, that wont usually produce that symptom, needing
to be off for minutes before it can be started again, and
you normally see problems with the cpu overheating first.
Clogged filters, dirt-encrusted fan blades or heat sinks, something blocking
air inlets or outlets, some fan not spinning, ...
Click to expand...

Unlikely. Much more likely to be a power supply or motherboard fault.
 
Open the cover of the PSU (unplugged of course).
You will likely find years of dust cloggin the heat sinks.
 
Eric Gisin said:
Open the cover of the PSU (unplugged of course).
You will likely find years of dust cloggin the heat sinks.
Click to expand...

Doesnt normally produce that effect of needing to be off for minutes.
 
CWatters said:
Check the CPU temperature reported by the BIOS after an hours use.

Check the CPU heatsink - on mine you need to use a torch because grey dust
looks much like aluminuim so it's hard to see if the heatsink is blocked
dust. If that's ok consider replacing the power supply.
Click to expand...

Uh, CWatters is using the UK definition of torch = flashlight, not the
US definition of torch = welding apparatus.
 
CWatters said:
Check the CPU temperature reported by the BIOS after an hours use.

Check the CPU heatsink - on mine you need to use a torch because grey dust
looks much like aluminuim so it's hard to see if the heatsink is blocked
dust. If that's ok consider replacing the power supply.
Click to expand...

Uh, CWatters is using the UK definition of torch = flashlight, not the
US def. of torch = welding apparatus.
 
Doesnt normally produce that effect of needing to be off for
minutes.
Click to expand...

I disagree.

Thermal sensors are usually designed to have hysteresis in their
behaviour, to avoid switching 'chatter' problems. The result is that
there is often a significant difference between the cut-out trigger
temperature and the reset temperature, hence the time delay while the
system cools.

If a thermal cut-out is triggering shutdown, it could be in the PSU,
the motherboard or the CPU chip.
 
I disagree.
Click to expand...

Your problem.
Thermal sensors are usually designed to have hysteresis
in their behaviour, to avoid switching 'chatter' problems.
Click to expand...

Few power supplys have thermal sensors and even less
shut down because of the dust that accumulates inside them.
The result is that there is often a significant difference
between the cut-out trigger temperature and the reset
temperature, hence the time delay while the system cools.
Click to expand...

See above.
If a thermal cut-out is triggering shutdown, it could be in the PSU,
Click to expand...

Hardly ever.
the motherboard or the CPU chip.
Click to expand...

Or it could just be a faulty power supply or faulty motherboard
with a temperature sensitive fault. Much more likely in fact.
 
Previously Lil' Dave said:
Would suspect cooling capacity of the power supply itself. Probably
shutting down automatically to protect from overheat, and remains that way
until it cools down enough for a restart. If the power supply is the single
way for heat to leave the PC, then check for impeded air flow into the PC
and into and out of the power supply.
Click to expand...
The electrical part of the power supply is not a suspect here, as you would
have problems starting the PC to begin with due to increased starting
current needed.
Click to expand...

I would not rule it out completely, but you have a point.

Arno
 
Evidence?
Click to expand...

The systems I have seen reported fail like that.

Even you should be able to find quite a few using groups.google

The evidence that few power supplys have
thermal shutdown is even easier to find.
 
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