Alpha Geek: How to replace a dead power supply

by Rick Broida

Click to viewPower supplies die. You never know when it's going to happen, but it's always at the worst possible time. You hit the power button and your PC just sits there. Idle. Quiet. Dead. At least hard drives have the courtesy to make that wrenching death-rattle when the end is near. But not power supplies: They just give up the ghost. Poof.

Fortunately, it's not impossible to replace one on your own. It's tricky, yes, and a bit time-consuming, but it's something any self-respecting lifehacker should learn to do. Plus, it'll save you upwards of $100 at the local computer shop, and that's always a good thing.

Here's how to extract and replace a power supply and, in the process, resurrect your fallen PC.

Step 1: Open up your PC

You gotta break some eggs to make an omelet. Start by unplugging the cord from the back of the power supply, then remove the case lid. There should be a label on the power supply that identifies the brand and model number. Write this down, as you'll probably want to order an identical replacement (more on that in a minute).

This would probably be a good time to blow out the dust that's accumulated inside the case. An ordinary can of compressed air will do the trick, though I recommend hauling the case out to the garage first—you'll be amazed by how much dust comes flying out of that thing. Here's more on how to evacuate PC dust bunnies while you're inside the case.

Step 2: Order a replacement power supply

The first order of business is to obtain a replacement for the dead power supply. Although these things are interchangeable to a point (a 300-watt ATX model is pretty much a 300-watt ATX model), I strongly recommend choosing an identical replacement. That way you can be absolutely sure it'll fit the available space and come with all the necessary power leads.

If you're in a hurry, you can call around to the local computer shops, but it's unlikely they'll have the exact model you need. Next stop: your computer vendor's web site. With any luck they'll make it easy for you to find and order a replacement. If you strike out there, try a Google search for the power supply brand and model number (such as "Bestec ATX-250-12Z"). Chances are good you'll find at least a few resellers that stock the PS.

Prices range from $20 to $100, though on average you'll spend about $40. That's what I paid for the 250-watt Hipro power supply I just ordered for my dead ABS Ultimate E2 media center—not including $11 for shipping.

Alpha Geek: How to replace a dead power supply

Step 3: Take "before" photos

Removing a power supply from a PC requires you to disconnect its leads from several places: the hard drive, the optical drive, and various spots on the motherboard. There may also be a lead connected to a front panel. Before you pull a single plug, grab your digital camera and snap some photos of the case interior, including one of each lead's location. Believe me: Once your PC is torn apart, you'll have a hard time remembering where everything goes.

Depending on the size of your case, some plugs may be hidden by cables, drive cages or other infrastructure. Just do the best you can to photo-document the power supply's connections.

Alpha Geek: How to replace a dead power supply

Step 4: Disconnect the power leads

Now for the surgery. Let me preface this by saying that you may not be able to reach all the power connections without first disassembling parts of the case. My aforementioned ABS system is the most extreme example of this: Because it's an ultra-compact, stereo component-style case, everything's jammed in tight. I had to remove the front panel (and the DVD drive along with it), the hard drive and the expansion-card risers—all to get to the main power leads on the motherboard.

You probably won't have quite so many innards to dissect, but if you do have to remove any internal components, keep snapping photos so you'll be able to review how it looked. At the same time, document your steps so you can perform them in reverse when installing the new PS. You can keep it simple: "1. Removed four screws from hard drive cage. 2. Removed hard drive cage to access front-panel power lead."

Speaking of screws, if you wind up removing more than a few, keep them organized. Grab a sheet of paper, cluster any "related" screws together, draw a circle around them, and then write a note indicating where they go. Put a piece of clear tape over them so they don't get bumped out of the circle.

Alpha Geek: How to replace a dead power supply

Step 5: Remove the dead power supply


Step 6: Install the new power supply

Out with the old, in with the new. Make sure the replacement power supply is set to the correct voltage, which for U.S. users means 115 (look for the little red switch on the back: If it's showing 230, slide it to 115).


Step 7: Fire it up


Look at that: You just resurrected the dead. Go have a beer, you big sexy repair god, you.

Be sure to check out our past features on more ways to repair or upgrade your PC yourself:

Rick Broida, Lifehacker associate editor, nearly shed tears when his beloved media center died, but now that it has a new power supply, he can enjoy Star Trek: Voyager reruns again. His special feature, Alpha Geek, appears every Monday. Subscribe to the Alpha Geek feed to get new installments in your newsreader.