radio MITSUBISHI MONTERO 1987 1.G User Guide

8-196 AUDIO SYSTEM - Service Adjustment Procedures
SERVICE ADJUSTMENT PROCEDURES
ANTkNNA TRUMMER NOBNIAA
70R0351
1.
2.
3.
1.
2.
3.
4.
5. The antenna trimmer is essential for matching the antenna
with the radio in order to obtain the maximum sensitivity of
the radio.
It must be adjusted with the antenna actually mounted on
the vehicle. If the trimmer is not adjusted properly, the
radio suffers from not only low sensitivity but also noises,
su’ch as external noise and noise from passing vehicles.
In the following cases, therefore, adjust it as described
below.
(1) When radio is installed.
(2) If antenna is replaced.
(3) If radio has low sensitivity.
(4) If radio is noisy.
AkTENNA TRIMMER ADJUSTMENT
Mgke the following preparations for adjustment:
(1)’ Turn the ignition key to the “ACC” position.
(2) Extend the antenna all the way.
(3) Tune accurately to a station near 1,400 kHz in order to
receive a broadcast in as weak an electric field as can
be barely received. If there is no station near 1,400 kHz,
tune to any high-frequency station (above 1,000 kHz)
available. If there are two or more stations near 1,400
kHz, choose the louder one.
(4) Set the volume control to the proper volume.
(5) Set the tone ccontrol to treble position.
Be sure that preparations 1 through 5 have been correctly
made.
Insert a screwdriver into the trimmer adjusting hole.
Tumrn the screwdriver clockwise or counterclockwise for
maximum sensitivity (maximum broadcast wave sound).
If the optimum sensitivity point cannot be found, check for
an antenna malfunction or a broken wire.
NOTE
The antenna trimmer of an electronic tuning radio does not
require adjustment.
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AUDIO SYSTEM - Radio and Tape Player e-197
RADIO AND TAPE PLAYER
REMOVAL AND INSTALLATION NOINJAF
16W1519
Post-installation Operation l Adjustment of Antenna Trimmer
(Refer to P.8-196.) Removal steps
1. Knob
2. Plug
3. Center console
4. Connection of center panel wiring har-
ness to front wiring harness connector 7. Radio
8. Tape player
9. Box (Vehicles without tape player)
5. Radio panel
6. Radio bracket NOTE
Reverse the removal procedures to reinstall. 1 STB Revision

8-200 AUDIO SYSTEM - Antenna/Noise Suppression
3. REMOVAL OF FRONT FENDER PANEL
Refer to GROUP 23 Body-Front Fender
SEFiVlCE ff OINTS OF INSTALLATION
3. IbSTALLATION OF FRONT FENDER PANEL
Refer to GROUP 23 Body-Front Fender.
NOISE SWPRESSION N08NOAA
I. Noise interfering with radio reception may be roughly
classified as follows:
(1) Noise produced by the vehicle itself
Noise from the ignition circuit, alternator circuit, etc
(2) Noise generated in the radio itself
Thermal noise from transistors, IC, resistor, etc.
(3) Atmospheric noise
Noise from other cars, neon signs, etc.
2. The radio has devices to suppress noise of the radio itsel f
3. and atmospheric noise, but it is difficult to eliminate them
completely. Noise produced by the vehicle includes whin-
ing from the alternator system, and a strong, impulsive,
fast popping noise from the ignition system.
Before performing any checking or adjustments, first
confirm the following points.
Adjust the antenna trimmer completely.
Set the push buttons (tuning) properly.
Extend the antenna all the way.
PREVENTION OF IGNITION CIRCUIT NOISE
A resistance-equipped cable is used for the high-tension cable
in order to prevent noise; however, if any noise from the
ignition circuit does occur, check the tightness and ground
connection of the positive (+) terminal of the noise filter, and,
if necessary, check the noise filter.
Caution
Be careful not to connect the noise filter to the hightension
cable; doing so could damage the noise filter.
PREVENTION OF OTHER CIRCUIT NOISE
1. For other noises, take necessary corrective actions in
accordance with the following items and the NOISE
SUPPRESSION CHART.
2. Polish the grounding cable terminal, and connect it proper-
ly.
3. Polish the pillar antenna ground terminal, and connect it
properly.
4. Ground electric parts completely.
5. Keep the antenna cable and speaker lead wire away from
other electric wiring.
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AUDIO SYSTEM - Noise Suppression 8-201
NOISE SUPPRESSION CHART
Symptom
Unusual noise related to
engine speed. ’ Remedy
Securely ground the engine, frame and/or body and engine
hood.
- Ground wire
16E71C
“Clatter” noise related to the
Turn signals
flashing of turn signal lights Connect a 0.5 FF noise-suppression capacitor to the 6 terminal
of the flasher unit.
Abnormal noise when
the horn is operated. Horn ?L - 0.5pF noise suppression
capacitor
16E71:
1. Connect a 0.5 FF noise-suppression capacitor to the + B
terminal of the horn.
2. For an FM radio, connect an LC filter to the horn terminals.
Noise when the wind-
shield washer oprates. Washer motor Horn LC filter
16E71:
1. Connect a 0.5 PF noise-suppression capacitor between
the terminal of the washer motor and the power source
wire.
2. For an FM radio, connect an LC filter between the terminal
of the washer motor and the power source wire.
Unusual noise when the
engine is started. Water tempera-
ture gauge unit Connect a 0.1 p,F noise-suppression capacitor to the terminal o
the water temperature gauge unit.
0.1 PF noise suppression
capacrtor
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