Power Supply Problems

The PC power supply is probably the most failure-prone item
in a personal computer. It heats and cools each time it is
used and receives the first in-rush of AC current when the PC
is switched on. Typically, a stalled cooling fan is
a predictor of a power supply failure due to subsequent
overheated components. All devices in a PC receive their DC
power via the power supply.

A typical failure of a PC power supply is often noticed as
a burning smell just before the computer shuts down. Another
problem could be the failure of the vital cooling fan, which
allows components in the power supply to overheat. Failure
symptoms include random rebooting or failure in Windows for
no apparent reason.

For any problems you suspect to be the fault of the power
supply, use the documentation that came with your computer.
If you have ever removed the case from your personal computer
to add an adapter card or memory, you can change a power
supply. Make sure you remove the power cord first, since
voltages are present even though your computer is off.

Power Supply Improvements

Recent motherboard and chipset improvements permit the user
to monitor the revolutions per minute (RPM) of the power
supply fan via BIOS and a Windows application supplied by the
motherboard manufacturer. New designs offer fan control so
that the fan only runs the speed needed, depending on cooling
needs.

Recent designs in Web servers include power supplies that
offer a spare supply that can be exchanged while the other
power supply is in use. Some new computers, particularly
those designed for use as servers, provide redundant power
supplies. This means that there are two or more power
supplies in the system, with one providing power and the
other acting as a backup. The backup supply immediately takes
over in the event of a failure by the primary supply. Then,
the primary supply can be exchanged while the other power
supply is in use.