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Five-step Troubleshooting
1.
Verify
The
Complaint
Turn on
all the components in the problem circuit to
verify the customer complaint. Note the symptoms.
Do not begin disassembly or testing until you have
narrowed down the problem area.
2.
Analyze The Schematic
Look up the schematic for the problem
circuit.
Determine how the circuit is supposed to work by
tracing
the
current paths from the power feed
through the circuit components to ground
.
If
several
circuits
fail at
the
same time, the fuse
or
ground is a
likely
cause.
Based
o
n the
symptoms and
your
understanding of
the
circuit
operation,
identify one
o
r
more possible
causes
of the problem.
3.
Isolate Th
e
Problem
By
Testing
The
Circuit
Make
circuit
tests to check the diagnosis you made
in step
2. Keep in mind that a
log ical,
simple proce-
dure is the key to efficient troubleshooting.
Test
for
the
most
likely
cause of
failure
first. Try to
make
tests at points that
are easily
accessible.
4.
Fi
x
The
Problem
Once the specific
problem is
identified,
make th
e
repa ir.
Be
su
re
to use proper tools
and
safe proce-
dures.
5.
Make Sure
The
Circuit Works
Turn
on
all
compone
nts
in
the
repaired
circuit in
all
modes
to
make
sure you've
fixed the entire
prob-
lem.
If
the problem was a blown fuse, be sure to
test
aU
of the
circuits on the
fuse. Make sure no new
problems turn up and the
origi
na
l
problem does
not
recur.
Wire Color Codes
The following
abbreviatio
n
s are
used
to
identify
w
ire
colors
in
the
circuit
schematics:
WHT
.............................
White
YEL
..............................
Yellow
BLK
..............................
Black
BLU
........
. ............
Blu
e
GRN .............................
Green
RED
.............................. Red
ORN
................. ....... .....
Orange
PNK
..................... .........
Pink
BRN
..............................
Brown
GRY
..............................
Gray
PUR
..............................
Purp
le
LT BLU
.................. ....... Light
Blu
e
L T
GRN
........................
Light
Green
Th
e
wire insulation
ha
s
one
co lor o
r
one
co
lor
w
ith
another color stripe. The second
color
is the stripe.
WHT/BLK
23-5
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Table of Contents
Troubleshooting
