Upgrading and Fixing Computers: Do-it-Yourself For Dummies®

Chapter 10. Replacing the Power Supply or Laptop Battery

Topics and tasks in this chapter

• Shopping for a power supply

• Setting up a UPS (uninterruptible power supply)

• Replacing your desktop PC's power supply

• Replacing your laptop's battery

You can't see it, but you can almost always hear it: Your desktop computer's power supply sits inside your computer's case in a corner with its cooling fan whirring away. Some fans add a pleasant, running-water ambience to the room. Others whine like a weed whacker.

Power supplies suck in the 120 volts from your wall outlet and reduce it to the lower voltages preferred by your computer's more sensitive innards. This seemingly simple task heats up the power supply, so it needs a constantly whirling fan to keep it cool.

The power supply's fan sucks hot air out of your computer's case and blows it out the hole in the back. In fact, if you keep your computer too close to the wall and don't move it for a while, the fan leaves a black dust mark on the wall.

Power supplies retire more quickly than many other computer parts. This chapter shows how to interview potential replacements and place the new one into its proper cubicle. (Power supplies are replaceable only on desktop computers. Laptops and netbooks grab their power from batteries, which I describe how to replace in this chapter's last task.)

Choosing a Compatible Power Supply

Almost all power supplies work fine with today's PCs. When choosing a replacement power supply, you need keep an eye only on these ...