Computer power supply failure

January 10th, 2008, 01:59 PM

The power supply on my wife's computer just died and in dying it wiped out the memory and may have damaged the motherboard or the CPU. Has anyone heard of this before?

January 10th, 2008, 02:32 PM


Never....unless we are talking about a power spike that took out the powersupply and also other components.

January 10th, 2008, 03:02 PM

This is a copy and paste I just found:

How to Diagnose and Replace a Failed PC Power Supply

When a PC power supply dies or begins to wear out, it must be replaced. With a few simple tools and the help of this guide, you can do this job yourself and save on expensive repair fees.
[edit] Steps

1. Familiarize yourself with proper ESD procedures before doing any kind of PC repair work which requires opening a computer. If you neglect this step, you may damage your computer.
2. Verify that the power supply needs replacement. The most obvious clue is that the system will do absolutely nothing when you hit the power button. If there is no sound and no monitor activity of any kind, the power supply has probably died. While this can also be caused by a faulty switch, it is usually the result of a burned-out power supply. To verify it is not the motherboard giving the problems, take a paper clip and insert it into the green and black terminals of the power supply plug after it is removed from the motherboard of the computer. Press the power button on the computer, if the fan spins inside the power supply, the motherboard is the problem. If the fan does not spin the power supply is dead. Another obvious clue is smoke or an odor of burning electronics, which will often (but not always) be noticed in a system that does absolutely nothing when you try to start it up.
3. Once you are satisfied that the power supply is the culprit, disconnect all external connectors (including the power cord) from the machine. This may include keyboard, mouse, network cable, speakers, etc.
4. Remove the case cover, placing any screws somewhere where they will not get lost.
5. 
   Identify the power supply unit. It will be connected to almost every component inside the computer case and will look something like this:
6. Using proper anti-ESD practices, disconnect all connectors which run from the power supply to the devices inside your PC.
7. Unscrew the mounting screws on the back of the case which hold the power supply in its housing. Place the screws in a handy location.
8. Gently remove the old power supply from the case. This is usually a simple process, but if there is very little room in your PC, it may be necessary to remove other components in order to get the power supply out. If you don't feel comfortable removing other components, replace the mounting screws and enlist the help of a PC expert before continuing. Do not try to yank a power supply out by force.
9. Purchase a new power supply of the same type as the old one. Most power supplies used in modern computers are of the "ATX" variety, but if you aren't sure, take the old unit to the store with you to compare. The simplest rule of thumb is that the new unit should be exactly the same width as the old one. It's fine if the new unit is a bit longer, as long as it will still fit into your case. Do not hesitate to ask the salesperson or technician for help in identifying the correct unit to purchase.
10. Unpack the new power supply and make sure it physically fits correctly. If the new unit has a large bottom mounted fan, the bottom rear bottom flange on some cases might get in the way. Add it to the case in the same place the old unit was, and use the mounting screws to fasten it down.
11. Using proper ESD procedures, connect the devices in your PC to the new power supply. The connections should be the same as they were before. It can require a bit of force to insert power connectors correctly, but if if you have to strain a great deal to push them in, you may be trying to connect them backward. It is very difficult to connect most Molex connectors improperly, but if you are determined (and strong) enough, it can be done. If you have to force too hard, try turning the connector around.
12. Verify that no cables or unused connectors are stuck in the CPU fan or touching other moving parts. If the CPU fan is stopped by a loose connector (or any other obstruction), the processor can be destroyed very quickly. You may wish to restrain unused cables to prevent them from getting tangled up in fans.
13. Replace and fasten down the case cover.
14. Replace all external connections to the back of the computer (power cord, mouse, keyboard, monitor, network cable, speakers, etc).
15. Power up the system and enjoy.
16. If your system doesn't start up correctly here, your failing power supply could have taken out the motherboard.

[edit] Tips

• If you suspect that your power supply is dying, replace it. A common clue which indicates a failing power supply is a high-pitched whining or grinding noise from the area of the case where the power supply is housed. Don't wait until the supply dies, because its failure can cause voltage problems which can ruin your motherboard, hard drive, or other components.
• Invest in a high quality power supply. Do some research before you purchase one. More wattage on the package doesn't mean better. Most home PCs don't actually use more than 300W even though this is not what power supply marketing people want you to know. The unit should provide adequate wattage for your needs. Don't skimp on the power supply, as you may regret it later. Power supplies that fail can damage other components in your computer, especially the motherboard.

[edit] Warnings

• If it's hard to remove a hard drive or CD/DVD drive power connectors, don't pull on it hard. It will come out suddenly and you'll likely cut your hand on sharp edges. Wiggle gently as you pull out.
• Don't attempt to open a power supply unit to attempt repairs or experiment with the parts if you're not familiar with working with high voltage circuits. The primary side of power supply operates around 340V DC. Power supplies contain capacitors which can hold dangerous charge for a few minutes. Usually the integral bleeder resistor ensures the capacitor does not remain charged for much longer than a few minutes. Most problems are not repairable by the home user. Refer the unit to a qualified electrician, or better yet, recycle it and replace it with a new or refurbished one as described here. The cost of having a power supply repaired is often more than the cost of a replacement unit.
• Sometimes, a failing power supply can continue to boot the system, causing only minor lockups and shutdowns. If this is the case, you should try to rule out other problems before replacing the power supply. While it is always best to replace a power supply you have good reason to believe is faulty, you should be sure that the problem is not caused by other factors.
• Do not do this on Dell Computers! Some Dell computers are designed to use an odd connector. If you use a standard power supply you may damage the power supply, the motherboard or both! This also goes for Compaq, some HP and other brand-name PCs. Check first!

January 10th, 2008, 03:26 PM

ok Juan, why do you think it's the power supply, and why do you think the memory and/or MB is cooked?

January 10th, 2008, 03:48 PM

First of all, the computer wouldn't boot up. Secondly, both RAM cards were dead.(tried them in another computer) Thirdly, with a new power supply and new RAM, the computer booted up right away. There are still some anomalies in the way the computer operates that make me suspicious that maybe the MB was not completely untouched.

January 10th, 2008, 04:14 PM

Then I would say a power spike was probably the culprit. With the new system, and any other electronics you have, may I suggest a good quality power bar with surge suppression. Considering where you live, it might be an idea to look at new breakers that can take care of suppression and also will "clean" the power to that circuit. Can end up saving not only computers but electronic appliances, T.V., and stereos.

January 10th, 2008, 07:40 PM

Can static discharges do something this bad to a computer?

Oh, and by the way this has been the most useful thread on the front page today.

January 10th, 2008, 07:43 PM


Static discharge can cook a memory stick.....screw up a hard drive..... screw up a MB....I haven't heard of anyone screwing up a power supply with a static discharge.

January 10th, 2008, 07:48 PM

Anything can go when a power supply dies, especially if it dying resuults in a huge surge.

Power supplies are one of the most important pieces of a computer but a commmonly overlooked piece.

The power supply units that come with OEM PC's are usually on the low end of quality. I highly suggest you purchase a PSU by Antec, Silverstone, PC Power and Cooling.

January 10th, 2008, 07:55 PM

This happened to me, twice. I think a third one (different machine) is dying, it's starting to make noise.

January 10th, 2008, 08:27 PM

I think you are missing the point Gerry. The PSU can give a voltage surge when it dies and that is what will kill other components like the memory, the motherboard, the hard drive, etc.

January 10th, 2008, 08:30 PM

Sorry...I have yet to see that happen....and I have replaced ALOT of dead or dieing PSU's.

January 10th, 2008, 08:35 PM

Thanks Durka
My wife said there was a small puff of smoke and a burning smell from the power supply unit(back of the tower case at least) when it failed. Didn't find out about the other components untill later.

January 11th, 2008, 08:15 AM

That sucks Juan

Before declaring the motherboard to be dead, try taking off the CMOS battery for a few minutes, put it back in and boot up.

January 11th, 2008, 08:29 AM

If you live in areas prone to electrical anomalies (surges, low-voltage etc.) and your computer is critical to your business/enterprise (or you don't perform regular back-ups) I'd suggest investing in a UPS system. Make sure that the unit you're looking at has line filtering and conditioning, as well, units that are "full-time" as opposed to swiched into line when a power condition outside the norm are sensed. These units (I was a dealer for American Power Conversions and Triplite (don't know if these units are still around...) but the stand-bys that are switched into circuit last longer (battery life) than do the "full-time" variety, but the added expense of the full-time units even with battery replacement assures you of significantly greater assurance from all aberrant line conditions than do the switched variety. Now it's been a while since I researched this hardware so my info is suspect... How about it Durka...had any up-close and personal experience with UPS/s?

January 11th, 2008, 08:54 AM

You can never go wrong with a UPS, provided you have the know-how to hook one up. I personally don't use one at home, as I live like to live life dangerously

At my work, we have redundant power to all the servers and backup generators in case the power ever goes out for a significant amount of time. The porn servers need their juice, otherwise there might be some sort of uprising in our subscriber base.

January 11th, 2008, 11:26 AM

We lived on Gabriola Island for over seven years. We must have lived a charmed life during that time because we had power outages at least once a week, sometimes three or four times a week. Once the power went on and off several times in a matter of seconds. I had to re-install Windows but nothing else was damaged. Power surges and outages were fairly common on the island but hard drives were the only thing that seemed to be effected. Went through about a dozen hard drives in the seven years