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Spontaneous shutdowns-voltage problem?

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  • CPUs
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April 15, 2003 3:21:59 PM

Not sure where to post this so here goes:

Athlon 2400/Asus A7N8X deluxe/1GB PC3200/Win XP corp/Koolance liquid cooled system running nice and cool.

I am having spontaneous shutdowns, always (it seems so far) during CD or DVD spin up, such as during software installation etc. The system just turns itself off with no preamble at all. Down.
I, using the Asus Probe software that came with the motherboard, have noticed that the +5V voltage monitor shows it fluctuating whereas the +3V and others are not. I upped the allowable error from 10% to 15% (maximum) and yet the problems persists, though possibly less frequently.

The power supply is and Enermax 430 watt basic whisper variety. Is a vlotage fluctuation sign of a defective power supply and can that fluctuation cause the shut downs I am experiencing?

I should say I have built two of these systems exactly the same and the other system has no problems and the voltage also appears stable as can be. Same power supply in both.

Any advice please?

Thanks
Rob Ostrander
Burlington, Vermont

More about : spontaneous shutdowns voltage problem

April 15, 2003 3:54:29 PM

Quote:
I upped the allowable error from 10% to 15% (maximum) and yet the problems persists, though possibly less frequently.

All that you're doing there is making the software report the problem less frequently. It wouldn't affect the hardware in any way.

Quote:
Is a vlotage fluctuation sign of a defective power supply

Sometimes, yes. <i>Much</i> more often though it is a sign of a power supply that is being pushed past it's ratings by running hardware that consumes too much power. Given your description, I'd definately say that you simply have too much running for your supply to handle.

Quote:
can that fluctuation cause the shut downs I am experiencing?

Quite simply, yes. Spontanious shutdowns and restarts are almost always power related.

Quote:
I should say I have built two of these systems exactly the same and the other system has no problems and the voltage also appears stable as can be. Same power supply in both.

That really means absolutely nothing. Chances are that all three of the systems are right on the edge of what the power supplies can actually handle. Thanks to the typical variances in power consumption, the other two systems use less power even though they are built from theoretically identical parts.

Of course, any variations in the room temperature or dust accumulation could also be responsible for lowering the capacity of any one power supply more than the others.

Quote:
Any advice please?

Get a better power supply.

<font color=blue><pre>I'm proud to be an American,
who served my country in the US Air Force,
to protect the rights of my fellow Americans,
to hold protests against others like me.</pre><p></font color=blue>
April 15, 2003 4:00:21 PM

depends on how much the voltages are fluctuating? If it is .02 then thats normal .. if it's going form like 5 to 1 then thats a bad power supply. I would think anyway. I'm no engineer but that seems common sense to me.

Life is irrelivent and irrational.

<A HREF="http://www.anandtech.com/mysystemrig.html?id=9933" target="_new"> My Rig </A>
April 15, 2003 7:34:02 PM

I have an enermax 430 watt athlon approved power supply which is just fine, although possibly defective, but plenty powerful.

By changing the percentage variance before shut down i was hoping not to eradicate the problem, but change my computer's threshold at which it would percieve the fluctuations AS a problem.

I appreciate your efforts and response. I really do. But I don't think I have given you enough information for you to assume I am over-burdening my power supply. That is far from the truth and I am underusing the power available to me if anything.

As for dust, these supplies and the entire rest of the system have been out of the box for a week. Nice and clean.

Thanks
Rob O
April 15, 2003 8:46:27 PM

Quote:
As for dust, these supplies and the entire rest of the system have been out of the box for a week. Nice and clean.

That is always good. :)  I simply asked because many people re-use cases and power supplies and often neglect to clean their power supples. And a dusty power supply is an unhappy power supply. Heh heh.

Quote:
By changing the percentage variance before shut down i was hoping not to eradicate the problem, but change my computer's threshold at which it would percieve the fluctuations AS a problem.

I understand what you were trying to do. What I'm saying is that what you actually did do is not what you were trying to do.

Changing the settings in the Asus Probe only changes when Asus Probe decides to report a problem. Since your system is crashing, the Asus Probe software has no affect on the situation. Even if it weren't crashing, all that Asus Probe would do is warn you of a problem, not shut down your PC because of a problem.

Quote:
I appreciate your efforts and response. I really do. But I don't think I have given you enough information for you to assume I am over-burdening my power supply. That is far from the truth and I am underusing the power available to me if anything.

You've stated that you're using an AXP 2400+, the second-most power consuming CPU that AMD makes according to AMD's electrical specs. You've put it on an Asus A7N8X Deluxe, a motherboard known to be sensitive to power inadiquacies. You have a Koolance watercooling system, which if it is one of the models powered by your PC instead of plugging in seperately, is a known power drainer. Chances are that if you have a watercooler you also have a number of case fans installed over just using the power supply. Chances are also high that with as much as it costs to get the specs of your system that you did list, other your system will also have:
* one of the latest power-hungry video cards (ATI Radeon 9500 or higher or nVidia GeForce FX)
* at least two cd/dvd devices
* at least two hard drives
Chances are also moderate that if you're running a watercooler you are doing so because you plan on OCing, which consequently increases the amount of power the CPU consumes (especially if you increased the vcore).

Now, assuming that my guesses about your system are even only 50% accurate, I'm still looking at a rather power-hungry system. If you would like, you could actually list all of your system's specs and we could calculate exactly what the maximum possible drain on each line is and what your power supply is specced to output. I really don't think that it's necessary though.

Why? Regardless of my knowledge of your system (or lack thereof) you've already been kind enough to provide more than enough information on the symptoms to diagnose solutions, which I appreciate.

Now, your problem seems to lie primarily in your 5V line, which is your spindle line. This is why the fluctuations occur during cd or dvd spin-up. The problem is clear that your 5V line's amperage, for whatever reason, isn't sufficient for your system. There is a possability that your power supply is bad. There is a much higher possability that your power supply and all of your parts are perfectly within their tolarances, but that the 5V line's devices are on the high-end tolarance for amperage use and the power supply is on the low-end tolerance for 5V output.

So you have four choices:
1) Remove devices (such as the CD ROM) from the PC to make it stable by reducing how much power is used. If removing one or two devices fixed your stability problems, then your power supply <i>isn't</i> defective, just maxed out.
2) RMA the power supply and hope that it was either defective or at the low-end of it's 5V output tolerances and that the new power supply isn't. Of course, many places will charge a restock fee to RMA should the power supply test within it's tolerances.
3) Replace the power supply with a better one that has a higher 5V output. This is the one that I'd suggest, because better safe than sorry. You may not even need to go with a higher wattage, but simply shop around for a better 5V output.
4) Add a second power supply and move some of the 5V devices onto it.

These four choices are your only real solutions, and frankly, number one and number four are pretty silly at that. You can play around with your hardware all you like, but in the end chances are pretty high that you will either go with number two or number three. I personally suggest number three, which is why I suggested earlier that you get a better power supply.

<font color=blue><pre>I'm proud to be an American,
who served my country in the US Air Force,
to protect the rights of my fellow Americans,
to hold protests against others like me.</pre><p></font color=blue>
!