Power Supply Failures

Power supplies typically die one of two ways: slowly or instantly and forever. While the power supply is statistically most likely to fail completely when it’s been turned off (or when you attempt to turn it on again), it sometimes fails right in the middle of a session. In most cases, your PC seems to switch off and usually won’t respond when you try to turn it on again. If it does try to start, you may smell smoke or overheated parts.

If the power supply doesn’t engage, the power supply may be well on its way to burning out, if it’s not already dead. If the power supply starts but the fan doesn’t move, turn the PC back off immediately, disconnect power, and use a can of compressed air to clean any debris and dust from the fan before trying again.

Those of you who are familiar with power supplies for other types of devices may already know that the fan in a PC power supply can usually be removed, cleaned, and oiled to grease recalcitrant blades (a droplet of 3-in-1 Oil usually works for me) or replaced. Then the entire power supply can be mounted back inside the case and reconnected to the rest of the system. This is a bit too advanced for me to recommend to everyone, so I’ll let the adventurers among you proceed at their own risk with this caveat: The fan should not be reinstalled until it is fully clean and dry, and you must exercise extreme care in reassembling the fan into the power supply and in reattaching all the connectors from the power supply to the other parts of your system that require them.

Chapter 11, “Avoiding Power and Overheating Problems,” explains how to install a new power supply should you need to replace or upgrade your current power supply.

Tip 

Don’t underestimate the ability of an overtaxed power supply to cause problems on a PC. On a standard 200-watt PC power supply packed in many computers, it’s possible to run out of juice before you run out of devices you can install into your PC that need a connection from the power supply. Chapter 11 contains more information about this.