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Safety Guidelines
If
you are aware of the guidelines for working with
electrical and mechanical equipment and practice these
guidelines, you can work safely with this equipment.
You need not fear electricity, but you must respect it.
You should take every safety precaution possible and
observe the following safety practices while maintain-
ing IBM equipment:
1.
You should not work alone under hazardous
conditions or around equipment with dangerous
voltage. Always advise your manager if this is a
potential problem.
2.
Remove all power before removing or assembling
major compop.ents, working in the immediate area
of
power
supplies,
performing
mechanical
inspection of power supplies, or installing changes
in machine circuitry.
3.
Power
supplies,
pumps,
blowers,
motor
generators, and other units with voltages that
exceed 30 Vac or 42.4 Vdc must not be serviced
with power on when the unit is removed from its
normal installed position within the machine,
unless maintenance documentation clearly states
otherwise. (This is done to ensure that proper
grounding is maintained.)
4.
Unplug the power supply cord whenever possible
before working on the machine. The wall box
switch, when turned off, should be locked in the
off position or tagged with a DO NOT OPERATE
tag (form Z229-0237). Be aware that a non-IBM
attachment to an IBM machine may be powered
from another source and controlled by a different
disconnect or circuit breaker.
5.
When it is absolutely necessary to work on
equipment having exposed live electrical circuitry,
observe the following precautions:
a.
Another person familiar with power-off
controls must be in the immediate vicinity.
(Someone must be there to turn off power if
it should become necessary.)
b.
Do not wear any jewelry, chains, metallic
frame eyeglasses, or metal cuff links. (In the
event of contact, there will be more current
flowing because of the greater contact area
afforded by the metal.)
c.
Use only insulated pliers, screwdrivers, and
appropriate probe tips/extenders. (Remem-
ber, worn or cracked insulation is unsafe.)
d.
Use only one hand when working on ener-
gized equipment. Keep the other hand in
your pocket or behind your back. (Remem-
ber, there must be a complete circuit for elec-
trical shock. This procedure helps eliminate
a path that could complete a circuit through
you.)
e.
When using test equipment, be certain that
controls are set correctly and that insulated
probes of proper capacity are used.
f.
Avoid contacting ground potential (metal
floor strips, machine frames, and so on); use
suitable rubber mats purchased locally, if
necessary.
6.
Follow special safety instructions when working
with extremely high voltages. These instructions
are outlined in CEMs and the safety portion of
maintenance documentation. Use extreme care
when checking high voltage.
7 .
Avoid use of tools and test equipment that have
not been approved by IBM. Electrical hand tools
(wire-wrap guns, drills, and so on) should be
inspected periodically.
8.
Replace worn or broken tools and test equipment.
9.
After maintenance, restore all safety devices, such
as guards, shields, signs, and ground leads.
Replace any safety device that is worn or defec-
tive. (These safety devices are there to protect
you from a hazard. Don't defeat their purpose by
not replacing them at the completion of the
service call.)
10. Safety glasses must be worn when:
Using a hammer to drive pins, and so on.
Power hand drilling.
Using spring hooks and attaching springs.
Soldering, wire cutting, removing steel bands.
Parts cleaning, using solvents, chemicals, and
cleaners.
Working with electrolytic capacitors that
have blowout plugs.
Use safety glasses for all other conditions that
might be hazardous to your eyes.
11. Never assume that a circuit is deenergized. Check
it first.
Safety Guidelines
iii
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