Jeep J-10 Series 1982 Technical & Service Manual page 1223

ANTENNA
BASE
ADJUSTMENT 4
SWR
READING
3.5
3
2.5
2
1.5-+
1 10 20 30
CHANNELS
SPLITTER ADJUSTMENTS 80703
Fig. 3V-19 Typical SWR Curve
NOTE: Although you are not talking while checking
VSWR, a carrier signal is being transmitted which can
eliminate another transmission. Try to pick a time when
the channel is not in use to check VSWR.
SPEAKERS
Speakers have an impedance of either 3.2 or 8 ohms. A
speaker should be replaced with a speaker having the
proper part number. If the exact replacement is not
available, select a speaker which matches the ohm value
stamped on the radio chassis with a black ink stamp.
AM/FM stereo radios are more critical in the selection
of a speaker than are AM radios. A noticeable deteriora
tion in sound will be noticed if the correct speaker is not
used.
Stereo speakers are paired together for a truer stereo
sound, right front with right rear, left front with left
rear.
Speaker Repairs
A speaker, once it has been damaged, is usually not
repairable and should be replaced. Defective speakers
usually have one or more of the following symptoms:
• Loose mounting.
• Screws or other objects stuck to back of magnet.
• Audio distortion, particularly on the low frequency
notes and at high volume.
• Rattles and buzzes caused by foreign material hit
ting or rubbing against the speaker cone.
•Raspy noises caused by foreign matter inside the
speaker restricting free movement of the speaker
cone.
•Muffled sound caused by speaker opening
obstruction.
40
RADIO SOUND SYSTEMS 3V-15
Use a light to check the speaker openings).
If the entire speaker is not visible through the speaker
grille openings, remove the obstruction as follows:
Front Door Speakers
(1) Remove door trim panel lower screws.
(2) Carefully lift the door trim panel away from
door to expose speaker.
(3) Cut out excess water dam paper around speaker.
(4) Install door trim panel lower screws.
NOTE: Be sure the speaker mounting screws are tight
ened securely.
Speaker Harness Test
Ground Condition
(1) Disconnect speaker feed wires at radio con
nector and each individual speaker.
NOTE: When reconnecting the speaker harness to the
radio, be sure the antentw. lead-in cable is fully engaged
in the radio socket.
(2) Connect one lead of an ohmmeter to the speaker
feed wire and the other lead to a good ground. An in
finity reading should be indicated. Check each individ
ual speaker wire in this manner.
(3) If resistance is indicated on the ohmmeter, the
wire being checked is grounded.
NOTE: Grounded speaker harnesses are generally
caused by screws piercing wire harness.
Short Condition
(1) Disconnect speaker feed wires at the radio con
nector and at each individual speaker.
(2) Connect ohmmeter leads to speaker feed wires
at the radio connector.
(3) An infinity reading should be indicated.
(4) If resistance is indicated on ohmmeter, the feed
wires being checked are shorted.
Speaker Test
Speakers may be isolated for grounds by testing the
impedance with an ohmmeter. Connect ohmmeter be
tween the two speaker leads. The specified value should
match the ohm value stamped on the radio chassis.
Speaker Replacement
CJ and Scrambler Models
To remove the AM speaker, remove the four attaching
nuts from the mounting studs.