Hardware Reference
In-Depth Information
• Don't overlook the simple or obvious. Double- and triple-check the installation and
configuration of each component.
• Keep in mind that the power supply is one of the most failure-prone parts in a PC. A
high-output(500Worhigher)“known-good”sparepowersupplyishighlyrecommen-
ded to use for testing suspect systems.
• Cables and connections are also a major cause of problems, so keep replacements of
all types on hand.
Before starting any system troubleshooting, you should perform a few basic steps to en-
sure a consistent starting point and to enable isolating the failed component:
1. Turn off the system and any peripheral devices. Disconnect all external peripherals
from the system, except for the keyboard and video display.
2. Make sure the system is plugged into a properly grounded power outlet.
3. Makesurethatakeyboardandvideodisplayareconnectedtothesystem.Turnonthe
video display, and turn up the brightness and contrast controls to at least two-thirds of
the maximum. If you can't get any video display but the system seems to be working,
trymovingthecardtoadifferentslot(ifpossible)ortryadifferentvideocardormon-
itor.
4. To enable the system to boot from a hard disk, make sure no floppy or optical discs
are in any of the drives. Alternatively, put a known-good bootable floppy or optical
disc with diagnostics on it in a drive for testing.
5. Turn on the system. Observe the power supply, chassis fans (if any), and lights on
eitherthesystemfrontpanelorpowersupply.Ifthefansdon'tspinandthelightsdon't
light, the power supply or motherboard might be defective.
6. Observe the power-on self test (POST). If no errors are detected, the system beeps
once (if the computer has a speaker in the case) and boots up. Errors that display on-
screen ( nonfatal errors) and that do not lock up the system display a text message that
varies according to BIOS type and version. Record any errors that occur and refer
to the POST error codes earlier in this chapter for more information on any specific
codes you see. Errors that lock up the system ( fatal errors) are indicated by a series of
audible beeps on systems that have a built-in speaker.
7. Confirm that the operating system loads successfully.
Problems During the POST
Problems that occur during the POST are usually caused by incorrect hardware config-
uration or installation. Actual hardware failure is a far less-frequent cause. If you have a
POST error, check the following:
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