28 Computer Service and Repair
In general, before opening the case to begin
work, disconnect the electrical power from the
computer. The recommended practice is to unplug
the ac power cord from the computer’s power
supply. The reason is many motherboards and
power supplies maintain a small electrical current
to some critical parts when the computer is turned
off. After the powering off a computer with the
on/off switch, you can actually see small lights
known as LEDs lit on the motherboard.
Removing jewelry before working inside a
computer case is also recommended. Jewelry can
snag on electronic components, damaging the
component. If the component was accidentally
energized, the jewelry could make an excellent
electrical path, causing electric shock.
One of the most common work-related injuries
is the back injury caused by lifting heavy objects.
Most physical injuries can be avoided when
safety standards are followed. A comprehensive
source of safety information for all occupations is
regulated by the Occupational Safety and Health
Administration (OSHA). OSHA is part of the
Department of Labor. It enforces safety standards
as well as trains, educates, and provides assistance
to employers and employees. Because there are a
great many work-related back injuries, OSHA has
developed a formula to determine the maximum
weight a person can lift without causing physical
injury. The formula includes factors such as the
height of the object being lifted, the distance it
is moved, and how many times the movement is
repeated within a given period. Most employers
restrict their employees to a maximum lift of
50 pounds. When the weight of an object exceeds
50 pounds, you should wait for assistance from
coworkers or special equipment designed for
lifting and hauling heavy objects. Figure 1-40
shows a typical cart used to transport heavy
equipment.
OSHA also provides standards for such areas
as ladders, electrical cords, grounding, working
surfaces, adequate lighting, and computer
workstation-related injuries. As a student and as
a computer technician, chances are you spend a
lot of time at a computer workstation. Check out
the OSHA website to learn how to avoid computer
workstation-related injuries. You may be surprised
at some bad habits you have developed over the
years.
Electrical Safety
Students who first enter a computer course
typically do not have an electronics background
that would enable them to understand fully
the electrical hazards in a computer laboratory
environment. As you progress through this
course, you will gain more knowledge about
potentially hazardous practices and devices. At
this point, the best practice to follow concerning
electrical safety is the following: Do not attempt to
open, inspect, or repair any electronic device that you
have not been trained on by your instructor or if you
have not received your instructor’s permission.
Goodheart-Willcox Publisher
Figure 1-40. Computers are moved using a cart which helps
protect the technician from injury.