Computer turns off Random

[patio]

Actually testing a PSU with a multimeter is an exercise in futility because of the simple fact it does not re-produce the conditions of a PSU under load.....

[BC_Programmer]

But, I believe, that is what westom is suggesting; to get it under load.

I'm curious how this technique can find problems with other components aside the PSU.

[westom]

Actually testing a PSU with a multimeter is an exercise in futility because of the simple fact it does not re-produce the conditions of a PSU under load.....

  How does a power supply in a computer with all peripherals active not create a power supply load?  A best load that a power supply could be tested with also means nothing internal is moved, disconnected, or changed.

  No better test of a power supply exists short of the thousands of dollar test station we would use. Best test is when the supply is until heaviest load.  Does anyone have that $thousands in test equipment?  Obviously the meter is the next best solution.   Once the OP provides those numbers, then facts will exist.  Currently not even one fact says what has failed - why that computer does not even power on.  Without those meter readings, what would you have him do?  Keep replacing parts on wild speculation until something works?

[BC_Programmer]

westom, Patio misunderstood your post. You certainly recommend testing it under load; Patio must have believed you meant to have this test performed when the PSU is unconnected from the PC load.

[westom]

Patio misunderstood your post. You certainly recommend testing it under load; Patio must have believed you meant to have this test performed when the PSU is unconnected from the PC load.

  I thought he might have been making that mistake.  No load testing is also why power supply testers are so close to useless.  It can report a defective supply.  But it cannot report a supply as good.  A power supply tester can easily report a defective supply as good because the test is conducted without load.

  How does the meter verify all components of a power supply 'system'?  Nothing is moved, disconnected, or modified.  Best test is a system accessing every peripheral simultaneously (multitasking).  Then any defect in that system is made obvious by multimeter numbers.

  A defective power supply can even boot a computer.  Only way to find that defect before it causes problems tomorrow or next year - mulitmeter numbers when supply is fully loaded.

[David1]

hey guys
today i was on the computer and i think i have a break though.
i look in the power supply and found no problems but when i was using it i ran a movie and skipped it fowards and back and the whole computer turned of.
i tried to press the power button but it didn't work.
even 2 min later.
i had to turn it of then back on from the wall to get it working.
i read in other forms that if you have to do this it is the power supply..

What do you guys think.
POWER SUPPLY)

[westom]

i had to turn it of then back on from the wall to get it working.
i

  Power supply controller has a protective lockout function that is cleared only by disconnecting power from the wall.  Power supply controller is separate from the power supply.  Your symptoms do not point to any facts; are only symptoms.  Again, without the meter, nobody can provide a definitive answer.  Your symptom points to maybe five different suspect - all of which were on the suspect list long ago.

  If you want a definitive answer, numbers are required.  That means a meter. No way around that need for numbers.  Otherwise do what those others did.  Just keep replacing parts until symptoms disappear.  Shotgunning may cure the problem or cure symptoms.

[patio]

Borrow a known good PSU of the same or greater wattage and swap it in there...
This should only take an overnite test to find out if it's the issue....

[David1]

where is this power supply controller?
also for $45 i am going to buy a thermalt power supply 430w

[westom]

where is this power supply controller?
also for $45 i am going to buy a thermalt power supply 430w

   Because the market is so full of consumers who only understand watts and dollars, supplies are often dumped into that market missing essential functions.  A minimally acceptable supply is about $60 retail.  That does not mean a supply selling at $60 has all functions.    But one way to take even higher profits is to forget some essential functions and sell at that lower price.  Power supplies that are missing essential functions will still boot a computer.

  Power supply controller is learned by using the meter.   Don't use the meter; then don't learn.

  Does a new supply work?  A defective supply can still boot a computer.  Responsible techs confirm that new power supply by taking 30 seconds using a multimeter.

[David1]

hi
i brought the thermalte 430w power supply for $45
i thought if this doesn't help i at least have a spare power supply.
so far it works great no problems.
i have put games on it and done pretty much everything.
for about 5 hours
ofcause time will tell if this is it.
the old power unit was a cheap one MEC 400w
everything on it just look cheap so even if me buying this unit didn't help i can but it in another computer.
i will monitor the computer very closely and if any problems occur i will let you all know.
thanks all again.
i will send a reply back in about 1 week or 2, to tell you how it went. if this happends to you.