computer shuts down unpredictably, not power supply.

[mpolans]

Help. My computer has been doing some wierd stuff. Shortly after starting up and getting to the desktop it would shut off (did that for about 4 days). Lately, it won't even get all the way through the POST before shutting down. If I push the power button to turn it back on, the front light flashes for a second, but it doesn't power on. It's got an Athlon XP 1700 processor. I haven't changed anything recently. Norton Anti-virus was up to date the day before this started happening a week ago. The hard drive is only a couple months old and works in a friend's computer. I just had the power supply out and it checked out fine. I took off the heatsink of the processor and applied new thermal paste. But nothing has helped.

Any ideas on whats wrong and how to fix it?

 

[paskuda]

How did you check your power supply ? By just measuring the power on output, or by installing it it other pc and using it for few hours ? I'm asking because I've had *exactly* the same problem recently and replacement of power supply helped, even though it seemed to be fine.

 

[mpolans]

Measuring power output.

 

[mpolans]

Does it make a difference?

 

[capT5]

I am having the same problem and I Installed a new power supply, but it still shuts down.
I went in to bios to check fans and sys temp, fans are normal and sys temp is 34C. Computer will stay running if I am in the bios but shuts down in XP and safe mode.
Any one?

 

[mpolans]

Heck, mine won't even stay running when looking at the bios stuff.

 

[franklin97355]

Check all the hardware (HD RAM) remove all parts not needed to run and try that.

 

[JDfarmBOY2006]

yeah see if it the power supply runs on your friends comp for a couple hours it could be that

 

[paskuda]

mpolans,
yes, that *does* make a difference. I did exactly the same first. Now I'm pretty sure that it's power supply problem, but check it anyway - install in some other computer and see if it works fine for few hours of work, bet it won't

 

[mpolans]

Got caught up in a couple things and haven't had time to try all the suggestions yet. Will report back in a day or two when I can.

 

[oldshrst]

I have just set up an Asus A8n-sli dlx and after two days encountered the same problem. The PC would shut off after a few minutes, right after post, ect. I went through the normal troubleshooting steps and couldn't identify the problem.

I just happened to look at the Power supply fan and thought it odd that it wasn't spinning. Check yours, the ps may be going into thermal shutdown. A sure symptom of it is that the longer the pc is resting for the longer it will run.

Hope that helps, and I hope it solves my problem too.

(btw my ps is a Antec neopower-480)

olds

 

[garebo]

capT5 still shuts down with a new power supply, and oldshrst, how old is your antec ps? Antec is pretty good and it could be that the fan isnt running as it isnt needed. On good power supplies there is a sensor and the fan only turns on if needed to cool, if not needed it stays off and saves your fan.

What you guys need to do is go to hardware store and buy a $5 to $10 multimeter. Its good for testing power supply and other computer and electronic gear, and even house circuits, so worth the money for sure.
Test the rails (power lines) going into your motherboard.
You have 12v,3.3v. 5 volt, and they can be checked at the top of the 20 pin power supply power connector where it plugs into the mobo, and you want to have it plugged into the mobo and turned on, of course.
There are tutorials in a few places, you can google one but if i recall there is one at tomshardware on the net. If you cant find one i will.
Anyway, you need to test the lines to see what kind of power is going into your mobo, often a bad power supply will show a low voltage.
Its a very low price for the multimeter and they are very handy, you can check continuity as well.









Good advice + great people = tek-tips

 

[ceh4702]

Why not just order a power supply tester. Unless there is a load applied you can not tell if the power supply is actually working.

If you do not like my post feel free to point out your opinion or my errors.

 

[garebo]

A power supply tester is handy and i have one but a multimeter is the same price and does so much more!!

I already explained that one must have a load on the power suppy to test it.
All you have to do is start up the system, inside or outside the case, leave everything alone. Simply use the leads from multimeter to test the power lines to make sure you are getting 12 volts, 3,3 volts, 5 volts. That is a lot better test than the power supply tester can provide and its easy to do. You only have to put the multimeter leads on the pins on the 20 pin power supply connector where it goes onto the motherboard.
There are tutorials on the net with pics.
And it is a much better test of the power supply to test it with a load on it, which is easily done, much better than a power supply tester! A power supply can be failing, on its last legs, and the power supply tester would show its fine, but a multimeter can show lines that are good and lines that are not good so a person can know for sure if their power supply is a cause of problems or not and wether it should be replaced. The power supply tester cannot do all that!






Good advice + great people = tek-tips

 

[garebo]

Put another way, a multimeter is about the best $5 to $10 a person can spend in the electronic testing department.


Good advice + great people = tek-tips

 

[oldshrst]

The Neo power 480 does have a variable speed fan, but I think that with most power supply fans they should never stop running completly.

This power supply has an optional connector that allows you to monitor the fan speed through the motherboard BIOS. They warn that the fan speed may be as low as 1000 rpm, and that some motherboards may not be able to register a value this low and will warn you of fan failure. It never states that the fan will stop.

So I think that the fan or the fan controller is faulty. I was really surprised that this happened as well, like you said Antec is supposed to be good stuff and that's why I bought it.

Hopefully I will get a replacement soon and we'll have to see how that one works out.

Olds

 

[garebo]

Im not saying that this is the case here, but i have a setup where the P4 2.4 cpu fan stops sometimes. IT goes back on when it needs to, and i am certain there are plenty more setups just the same, so i dont believe its true that just because the fan isnt running it means there is a problem.
Same as above for the power supply. My power supply fan doesnt run all the time it runs only when needed.

You may be able to get motherboard monitor to run on your system and it will tell you the temps of your mobo and cpu and fan speeds.


Good advice + great people = tek-tips