Replace Your Power Supply
"The fan inside my computer's power supply has started making an awful noise, and I'm afraid it's ready to bite the dust. Is it difficult to replace a power supply?"
How to Replace Your Computer's Power Supply
Your computer's power supply is a critical component, obviously. The power supply converts alternating current to direct current and feeds power to all the many components of your computer. But how can you tell if your power supply is powerful enough, or if it's about to die? How do you decide what kind and capacity of power supply to buy, and how difficult is it to replace a power supply yourself?
You know your power supply has died when you turn on the computer and absolutely nothing happens: no monitor flicker, no LED lights indicating disk activity, nothing. Then it's time to replace the power supply. You may get early warning of a power supply that is going to die soon. It generally takes the form of a high-pitched whining noise traceable to the power supply. You may also hear a buzzing sound, which could indicate that the power supply cooling fan is going bad. In some cases, you may detect a whiff of a burning smell. Do not let these symptoms continue for long!
An overloaded or overheated power supply can send voltage surges through your computer that can fry components. I've even heard of power supplies catching fire or belching out acrid black smoke. It's much cheaper to replace a power supply now than a CPU, hard drive, and DVD drive all at once later.
Which Power Supply Should You Buy?
The number of watts a power supply can deliver is directly proportional to its cost. Computer makers want to save manufacturing costs, so they tend to include power supplies that barely provide enough power for the components added at the factory. There is your first clue about how to tell if your power supply is adequate.
If you add or upgrade components that consume more power, make sure your power supply can supply the new total requirement. The power requirement of each component, in watts, should be available on the device itself or in its documentation. Add up all the requirements and compare the total to the watt rating of your power supply, which should be on the power supply's label.
Your computer's total power requirements should not be more than 80 per cent of the power supply's rating. The reason for this leeway is that components are usually labeled with their "running" power requirement, and the startup power requirement may be higher. You don't want to overload the power supply when you power-up the computer.
It doesn't hurt to buy a power supply that's beefier than you need. If your computer was equipped with a wimpy 250W power supply, it won't hurt to replace it with a 450W model. High end gaming systems may require 750W or 1000W power supplies. Your existing power supply will be labeled with the wattage, so use that as a guide an bump it up a few notches just to be safe.
I found some 450W power supplies at Tiger Direct and other online vendors for under $30, but prices do vary widely. Higher-priced power supplies tend to have better cooling fans, and by better I mean quieter. A noisy cooling fan is a great irritation.
Do It Yourself Power Supply Replacement
The good news is that power supplies are pretty easy to replace, and are not terribly expensive. For the purposes of this article, let's limit ourselves to desktop computers. Laptop repairs can be tricker, and are best left to a professional repair staff.
A desktop computer's power supply is typically a silvery metal box held snugly in a corner of the computer's case by brackets and screws. You can easily find the location of the power supply, even without opening the system unit. Just look on the back of the unit, where the primary AC power cable plugs in.
After unplugging everything that's connected to the system unit, you can open the case by loosening a few screws and sliding the cover panel(s) off. Open up the system unit, and you'll see a tangle of wires coming out of the power supply. Pairs and triplets of wires terminate in connectors of various shapes. These connectors plug into the components that need power: motherboard, hard drive, CD/DVD drive, etc.
You can remove the power supply by unplugging all the connectors that are feeding the various components, and then removing the screws that hold the power supply to the case.
After popping the new power supply in the system unit, reconnect the connectors to all the components. Each component will accept only a certain shape of connector, so you really can't go wrong. If the connector fits, it's the right set of wires. Just make sure you don't forget to connect anything.
Research power supplies for type of system you have: basic home user, high-end gamer, business, etc. Talk to people in computer user groups and online forums; they're generally enthusiastic about the finer points of hardware and will be more than happy to tell you which power supplies are ideal for your needs and budget.
Do you have something to say about replacing a power supply? Post your comment or question below...
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Posted by Bob Rankin on October 28, 2009 04:50 PM
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Article information: AskBobRankin -- Replace Your Power Supply (Posted: October 28, 2009 04:50 PM)
Source: http://askbobrankin.com/replace_your_power_supply.html
Copyright © 2005 - Bob Rankin - All Rights Reserved
Most recent comments on "Replace Your Power Supply"
(See all 17 comments for this article.)Posted by:
Dave C.
29 Oct 2009
If the fan is making noise, it may simply need to be cleaned, or oiled. "Dirt balls" are a common problem in a computer that runs a lot. Just need to vacuum out the dust- with the machine off, course.
To oil the fan, you need either a precision oiler, has a thin hypodermic like tube,(get it at hardware stores or model shop) or just a 3-in-1 like oiler.
Fan bearings usually are an oilite type, which can run dry after a few years. The bearing in in the center of the fan, and often found under a sticker and rubber plug seal. Pry off the sticker, and save it, also the rubber plug. Give the bearing a few drops of oil, and switch on, and let it run a minute or two, then top off with a drop or two, more. Wipe off the excess with a bit of paper towel or napkin and replace the rubber plug and sticker.
Usually you probably won't need to take the power supply out.
Posted by:
LynnS
29 Oct 2009
A question about laptops and power supplies. A few months ago, when I took my laptop (Dell) off the docking station, I got a blue screen when booting up, and was unable to use the laptop. When I re-attached the laptop to the docking station it worked fine. Then, about a week ago, my external monitor began to flicker on and off at least once a day - flickering will last about 1 minute, then stays on. Are these both symptoms of a dying power supply on the laptop?
EDITOR'S NOTE: I'm not sure about that. Isn't the external monitor powered separately? ie: plugged into a wall socket or power strip?
Posted by:
Carole
29 Oct 2009
I just had mine fail once again. I have had many problems with power supplies failing in the past (yet use a battery to prevent voltage spikes or brown outs). The symptoms are not always so obvious. Your computer may just seem a bit quirky. I am using a desktop utility that tells me if the voltage is spiking, good and free. However it was too late, a bad power supply already destroyed my 2 new hard drives... I had just replaced a failed drive a month ago. I believe next time I'll go with a better well know brand PSU.
Posted by:
Steve
30 Oct 2009
When my power supply fan started to make noise I replaced the fan and it has been working fine for about six months now. Fans are much cheaper than replace PSU's . I was fortunate my PSU fan was held in place with screws and not rivets.
Posted by:
Ron Perkins
30 Oct 2009
I would like to add that many Dell computer Power Supplies have a 24 pin Motherboard Connector. Most store replacement Power Supplies have a 20 pin Motherboard Connector. I am not sure these are 100% compatible, but one reference says the first 20 pins are the same, but I have not tried as I didn't want to fry someone else's computer. More info on this would be appreciated. I also know that some early Dell Power Supplies were NOT compatible, as they had different voltages wired into different Motherboard Power Connector pins and that could cause a major problem. Be cautious.
Posted by:
Mike Hampshire
01 Nov 2009
I have had computors since my first tandy 1000 and never had a power supply go bad. Why. I open the cases once a month and blow out fans in power supply and for the mother board. Check fan afterward and if it has any resistance to turning freely replace it. no heat build up = no faults
Posted by:
Fishplate
05 Nov 2009
We replaced a power supply in a computer today...MSI motherboard...in addition to the 24-pin main connector (labeled 20+4), it had the additional 4-pin power connector.
The power supply had two 4-pin plugs on the end of the wire, placed such that you could use one or the other...they might have been put there to fit an 8-pin socket, but I've never seen one. The wire loom was so tight that I couldn't see if htey were wired the same, but the plugs had slightly different shapes on them - one had two square pins and two rounded pins, the other had three rounded pins and one square pin. The plughs were labeled differently - as I recall, one was 4+ and the other was 4P.
Careful examination of the mobo showed two square pin sockets, so that's the plug I used...it worked, so I must have inferred correctly. Never seen a mobo with an 8-pin socket, so I don't know why the two plugs were tied so closely together.
Posted by:
noob
08 Nov 2009
This great guide.
http://www.xbitlabs.com/articles/coolers/display/system-wattage.html
Posted by:
Robert DiGrazia
18 Nov 2009
I turn my computer on and off daily. It remains plugged into live AC. Every so often, the AC goes away, either because of power failure, or because I unplug for a couple of days.
Whenever I start the computer after several hours not connected to AC, the power supply fan is noisy. The noise goes away after a few minutes. If the computer remains connected to AC when powered off, the fan is quiet when turned on.
Does the fan know when the computer is unplugged vs powered off?
Posted by:
Rob Mercer
27 Nov 2009
There is an excellent article about Buying a Power Supply by the Pound on the Directron.com website. There is a BIG difference in power supplies of the same wattage and how much they weigh, the more they weigh, the better they are manufactured. I'll take a heavy 450 watt power supply over a super light 600 watt one any day! Here's a link to the article...http://www.directron.com/psu.html