viii
CAUTIONS
z Observe and heed all CAUTION notices in the manuals and on the equipment. CAUTIONS call attention to information
about safeguarding equipment from damage.
HANDLING PRECAUTIONS FOR ELECTRONIC DEVICES SUBJECT TO DAMAGE BY STATIC ELECTRICITY
Place instrument or module to be serviced, spare parts in
conductive (anti–static) envelopes or carriers, hand tools
etc. on a work surface defined as follows. The work surface
must be conductive and reliably connected to earth ground
through a safety resistance of approximately 250 kilohms.
The surface must NOT be metal. (A resistivity of 30 to 300
kilohms per square is suggested.) Avoid placing tools or
electrical parts on insulators.
Ground the frame of any line–powered equipment, test in-
struments, lamps, soldering irons, etc., directly to earth
ground. To avoid shorting out the safety resistance, be sure
that grounded equipment has rubber feet or other means of
insulation from the work surface. The module being serv-
iced should be insulated while grounded through the pow-
er–cord ground wire, but must be connected to the work
surface before, during and after any disassembly or other
procedure in which the line cord is disconnected.
Exclude any hand tools (such as non–conductive plunger–
type solder suckers) that can generate a static charge.
Ground yourself reliably, through a resistance, to the work
surface; use, for example, a conductive strap or cable with
a wrist cuff. The cuff must make electrical contact directly
with your skin; do NOT wear it over clothing. (Resistance
between skin contact and work surface through a commer-
cially available personnel grounding device is typically 250
kilohms to 1 megohm.)
If any circuit or IC packages are to be stored or transported,
enclose them in conductive envelopes or carriers. Remove
them only with the above precautions; handle IC packages
without touching the contact pins.
Avoid circumstances that are likely to produce static charges,
such as wearing clothes of synthetic material, sitting on a
plastic–covered stool (particularly while wearing wool), comb-
ing your hair, or making extensive erasures. These circum-
stances are most significant when the air is dry.
When testing static sensitive devices, be sure dc power is
on before, during, and after application of test signals. Be
sure all pertinent voltages have been switched off while
boards or components are removed or inserted.
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