Hardware Reference
In-Depth Information
I've been in situations in which I've had a defective component and replaced it with an-
other(unknowntome)defective new componentandtheproblemremained.Notknowing
that the new part I just installed was also defective, I wasted a lot of time checking other
parts that were not the problem.
This technique is also effective because so few parts are needed to make up a PC, and the
known-good parts don't always have to be the same (for example, a lower-end video card
can be substituted in a system to verify that the original card had failed).
Troubleshooting by the Bootstrap Approach
Another variation on this theme is the “bootstrap approach,” which is especially good for
what seems to be a dead system. In this approach, you take the system apart to strip it
downtothebare-minimumnecessary,functionalcomponentsandthentestittoseewheth-
eritworks.Forexample,youmightstripdownasystemtothechassis/powersupply,bare
motherboard, CPU (with heatsink), one bank of RAM, and a video card with display and
then power it up to see whether it works. In that stripped configuration, you should see
the POST or splash (logo) screen on the display, verifying that the motherboard, CPU,
RAM, video card, and display are functional. If a keyboard is connected, you should see
the three LEDs (capslock, scrlock, and numlock) flash within a few seconds after power-
ing on. This indicates that the CPU and motherboard are functioning because the POST
routines are testing the keyboard. After you get the system to a minimum of components
that are functional, you should reinstall or add one part at a time, testing the system each
time you make a change to verify it still works and that the part you added or changed is
not the cause of a problem. Essentially, you are rebuilding the system from scratch using
the existing parts, but doing it one step at a time.
Many times problems are caused by corrosion on contacts or connectors, so the mere act
of disassembling and reassembling a PC will “magically” repair it. Over the years, I've
disassembled, tested, and reassembled many systems only to find no problems after the
reassembly.
Some useful troubleshooting tips include the following:
• Eliminate unnecessary variables or components that are not pertinent to the problem.
• Reinstall, reconfigure, or replace only one component at a time.
• Test after each change you make.
• Keep a detailed record (write it down) of each step you take.
• Don't give up! Every problem has a solution.
• If you hit a roadblock, take a break or work on another problem. A fresh approach the
next day often reveals things you overlooked.
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