Basic Techniques
You have to do a few things right if youre going to work on computer hard-
ware effectively. Here they are:
? Control static electricity. You absolutely have to control static elec-
tricity (also called electrostatic discharge, or ESD). Voltages you cant
see or feel can kill the chips in your computer.
? Follow careful, well-de?ned procedures. You get nowhere ripping
hardware or software apart and making random changes hoping
something will work. You have to have a carefully thought-through
sequence in mind. Youll want to change only one thing at a time
(and test the result) so you can isolate what causes different results.
? Use the proper tools. Were as guilty as anyone of using vise grip pli-
ers as a universal tool, but thats not the right way to go about work-
ing on computer hardware. The parts are relatively small and fragile,
so you must have tools appropriate to the job.
Static electricity
The hundreds of millions of transistors inside the chips in your computer are
fantastically small. Although the small size of the transistors makes the speed
and functionality those chips offer possible, that same small size reduces the
voltage the transistors can withstand. Heres a typical warning about the maxi-
mum ratings on chips:
Operating the device beyond the Absolute Maximum Ratings may cause
permanent damage. Exposure to stress beyond the Operating Conditions
limits speci?ed for the device may affect reliability.
Typical signal and power level operating conditions for the largest chips in
new computers are no more than 3 volts, down from the 3.3 volts and 5 volts
used just a few years ago. You cant feel static electricity at much below 30
volts, and you can easily generate thousands of volts without intending to. The
absolute maximum voltage rating for most chips is 6.5 volts; some are even
less. Because youre not likely to feel less than 30 volts, you can destroy a chip
without even feeling a tingle. Whats worse is that you can weaken a chip
(priming it to fail a little later), damaging it just short of complete failure.
Ultimately, your feet scuf?ng on the ground, clothes rubbing on you, and a
multitude of other small things can generate the ammunition that kills a chip.
Heres the no-compromises plan to prevent static electricity problems:
? Ground everything, including you. Its not enough to simply touch a
piece of metal static electricity can build back up simply from
your moving as you work. The best way to prevent a static electricity
discharge is to not let any charge build up to begin with. Grounding
everything connecting you, your tools, and the equipment to a
good ground takes care of this. A proper anti-static workstation
includes not only a grounded workbench, but also a ground mat, a
grounded wrist strap (which fastens securely around your wrist), and
foot straps. Grounds should connect through an unbroken wire to a
secure cold-water ground. (Be sure the pipe into the ground is an
unbroken length of metal, with no plastic sections.) If youre going all
out, consider grounded tools and a humidi?er. Increased water in the
air helps static charges bleed off.
? Avoid materials that build up static charges. Workbench tops
should be a conductive, anti-static material. Under no circumstances
should you work on a plastic, vinyl, carpeted, cloth-covered, ?nished,
or waxed surface. Parts should be stored in plastic bins or bags
made of conductive, anti-static material. Check bins and bags for
extraneous material that could cause static buildup.
? Floors should be conductive tile. Avoid vinyl, carpet, ?nished wood,
sealed or dusty concrete, and ?oor wax. You can get carpet spray to
minimize static buildup, but its not really the right answer.
Youll also want to keep static-building material out of your work
area. This includes most plastics, nylon, polyethylene, Styrofoam,
vinyl notebooks, cellophane, and adhesive tape. Clothing often
includes static-building material, so your best bet is to wear a con-
ductive smock.
? Avoid other people. Onlookers are inevitable, but without their own
anti-static protection, they can destroy in a second what youve
worked to protect. Keep people without appropriate anti-static pro-
tection at least 3 feet away from the work area so they cant touch
anything.
Obviously, you can work in a less protected environment, and realistically, a
work area like that is more than most homes and of?ces can afford. Many serv-
ice centers, operations that should take careful precautions, do with less pro-
tection than weve recommended above. Simplifying the protections increases
your risk, especially in a dry atmosphere, so well cover what you should do
for suf?cient protection with minimum fuss.
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