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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
untilyou 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. lf
several circuits fail at the same time, the fuse or
ground is a likely cause,
Based on the symptoms and your understanding of
the circuit operation, identify one or more possible
causes of the problem.
3. lsolate The Problem By Testing The Circuit
Make circuit tests to check the diagnosis you made
in step 2. Keep in mind that a logical, simp,e
procedure is the key to efficient troubleshooting.
Test for the most likely cause oI Iailure first. Try to
make tests at points lhat are easily accessible.
4. Fix The Problem
Once the specific problem is identified, make the
repair. Be sure to use proper tools and safe
procedures.
5. Make Sure The Circuit Works
Turn on all components in the repaired circuit in all
modes to make sure you've fixed the entire
problem. lfthe problem was a blown fuse, be sure
to test all of the circuits on the fuse. Make sure no
new problems turn up and the original problem
does not recur,
Wire Color Codes
The following abbreviations are used to identify wire
colors in the circuit schematics:
W H T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
W n r r e
Y E 1 . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . .
Y e l l o w
B 1 K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B l a c k
B 1 U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B l u e
G R N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G r e e n
R E D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
R e d
O R N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
O r a n g e
P N K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
P i n k
B R N . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B r o w n
G R Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G r a y
P U R . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . .
P u r p l e
1 T 8 1 U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
L i g h t B t u e
1 T G R N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
L l g h t G r e e n
The wire insulation has one color or one color with
another color stripe. The second color is the stripe.
WHT IBLK
22-5
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Table of Contents
Troubleshooting
