General Information 1-5
Safety
WARNING
LETHAL
VOLTAGES
ARE
PRESENT
INSIDE
THE
COMPUTER.
OBSERVE
ALL
WARNINGS
IN
THIS
MANUAL,
AND
OBSERVE
THE
FOLLOWING
SAFETY
PROCEDURES
AND
GUIDELINES.
General Safety Procedure
• Do
all
possible operations with the computer unplugged from the power source.
•
If
installation, maintenance,
or
repair must be done with the computer energized, take the
following precautions:
a.
Never work alone
in
high-voltage areas.
In
case of accidental shock, a
life
may
depend
on
rapid removal from the energized source
and
appropriate
first
-aid action.
b.
Employees working
in
high-voltage areas should know where to obtain respiratory
resuscitation and/or cardiopulmonary resuscitation
(CPR),
in
case a fellow worker needs
assistance.
c.
In
case of burns, treat only after the person
is
breathing
and
has a normal heartbeat.
•
If
primary wiring change
is
made, perform continuity test between power cord ground
and
metal chassis. Record results
on
Repair Order.
These simple precautions can save a
life.
Safety Guidelines
for
High-Voltage Testing
Here
is
a
list
of safety guidelines to be followed when working with voltages
in
excess of
SOV
dc
or
SOV
ac root-mean-square
(RMS).
1.
Know each step of the test procedure. Check the test setup to be sure the instruments are
connected properly
and
that
all
control settings are correct.
2.
Never defeat interlocks.
3. Never have
one
hand
on
chassis or other ground while measuring high voltages with a probe
held
in
the other hand. Use the
one
hand method, that
is,
probe
in
one
hand, the other
hand
behind the back or
in
a pocket.
4.
Make sure the probe being used has voltage insulation higher than the voltage being mea-
sured. Check wires
and
probes for cracked insulation
and
defects. If any defects are noted
do
not use until repairs are made.
5. Make certain that the instrument to
be
serviced
is
turned off
and
all
capacitors, CRTs,
and
high-voltage circuits are discharged before any component or hardware
is
removed
or
touched. Remember that a circuit can
be
lethally charged
if
a component
is
open
or
missing,
or
if a wire
is
disconnected or open, even with the ac power switch
off.
Isolated heat sinks can
also
be
statically charged.
6.
Make certain that instruments used for testing are used within their rated specification. Never
use instruments floated above their specified rating.
7.
Never reach around energized high voltage circuits. Always turn equipment off
and
discharge
the high voltage
first.
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