Mitsubishi Galant. Manual — part 645
RADIO WITH TAPE PLAYER AND CD PLAYER
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CHASSIS ELECTRICAL
54A-133
DIAGNOSIS
STEP 1. Retune the radio, and check that no
noise appears.
Q: Does the problem clear up when retuned?
YES :
Check that there is no noise.
NO :
Go to Step 2.
STEP 2. Check that the noise appears only in
certain locations and only with certain stations.
NOTE: Multipath noise and fading noise: Because of
the frequency of FM waves in extremely high, it is
highly susceptible to effects from geological
formations and buildings. These effects disrupt the
broadcast signal and obstruct reception in several
ways.
.
•
Multipath noise
This describes the echo that occurs when the
broadcast signal is reflected by a large
obstruction and enters the receiver with a slight
time delay relative to the direct signal (repetitious
buzzing).
•
Fading noise
This is a buzzing noise that occurs when the
broadcast beam is disrupted by obstructing
objects and the signal strength fluctuates
intricately within a narrow range.
Q: Does the problem appear only in certain locations
and only with certain stations?
YES :
The effect of an electrical field condition
(multipath noise, fading noise) could be the
cause. Check that there is not noise.
NO :
Go to Step 3.
STEP 3. Check that the connectors are properly
connected.
NOTE: For the corresponding connectors, etc., refer
to GROUP 90,Audio System <vehicles with four
speakers
> or <vehicles with seven
speakers
Q: Are the connectors properly connected?
YES :
Go to Step 4.
NO :
Check the condition of the connector. Refer
to GROUP 00E, Harness Connector
Inspection
. Check that there is no
noise.
STEP 4. Check that noise appears when the radio
switch is turned on while the vehicle is stopped.
NOTE: Static electricity noise: Body static electric
from the shock absorber rubber bushings used to
prevent vibration, tires, etc. occurs because of
separation from the ground, causing a buzzing noise.
There is no measures to discharge the static
electricity of the vehicle body. Check that there is no
noise.
Q: Does noise appear when the radio switch is turned
on while the vehicle is stopped?
YES :
Go to Step 5.
NO :
It may be static electricity noise.
STEP 5. Check that the radio is correctly
grounded.
Q: Is the radio correctly grounded?
YES :
Go to Step 6.
NO :
Tighten the screw securely. Check that
there is no noise.
STEP 6. Check that the antenna is correctly
grounded. (If noise appears when the antenna is
moved, this means the ground is not securely
connected.)
Q: Is the antenna correctly grounded?
YES :
Repair or replace the radio. Check that
there is no noise.
NO :
If rust is present on the antenna ground
screw, clean off the rust and tighten the
ground screw securely. Check that there is
no noise.
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CHASSIS ELECTRICAL
RADIO WITH TAPE PLAYER AND CD PLAYER
54A-134
Inspection Procedure 13: Ever-present Noise.
Diagnosis
Noise is often created by the following factors, and often the
radio is OK when it is checked individually.
•
Traveling conditions of the vehicle
•
Terrain of area traveled through
•
Surrounding buildings
•
Signal conditions
•
Time period
For this reason, if there are still problems with noise even after
the measures described in inspection procedure 8 to 15 have
been taken, get information on the factors listed above as well
as determining whether the problem occurs with AM or FM, the
station names, frequencies, etc. and contact the radio
manufacturer's service center.
Inspection Procedure 14: There is noise but no reception for both AM and FM or no sound from AM,
or no sound from FM.
DIAGNOSIS
STEP 1. Make sure that the check is being
conducted under special electrical field
conditions.
Example: In an underground garage or inside a
building.
Q: Is the check being conducted under special
electrical field conditions?
YES :
Go to Step 2.
NO :
Go to Step 3.
STEP 2. Check that proper performance is
obtained when the vehicle is moved.
Q: Is proper performance obtained when the vehicle
is moved?
YES :
The radio should sound normally.
NO :
Go to Step 3.
STEP 3. Check that tuning solve the problem.
Q: Does tuning solve the problem?
YES :
The radio should sound normally.
NO :
Go to Step 4.
STEP 4. Check the antenna plug and radio unit
connected
Q: Are the antenna plug and radio unit properly
connected?
YES :
Go to Step 5.
NO :
Reconnect the antenna plug and radio unit
properly. the radio should sound normally.
STEP 5. Check that the problem disappear if
another radio is used.
Q: Does the problem disappear if another radio is
used?
YES :
Repair or replace the radio. The radio
should sound normally.
Inspection Procedure 15: Poor reception.
DIAGNOSIS
STEP 1. Make sure that the check is being
conducted under special electrical field
conditions.
Q: Is the check being conducted under special
electrical field conditions (such as in an
underground garage or inside a building?
YES :
Go to Step 2.
NO :
Go to Step 3.
RADIO WITH TAPE PLAYER AND CD PLAYER
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CHASSIS ELECTRICAL
54A-135
STEP 2. Check that proper performance is
obtained when the vehicle is moved.
Q: Is proper performance obtained when the vehicle
is moved?
YES :
Check that a poor reception is resolved.
NO :
Go to Step 3.
STEP 3. Check that tuning solves the problem.
Q: Does tuning solve the problem?
YES :
Check that a poor reception is resolved.
NO :
Go to Step 4.
STEP 4. Check that the problem is limited to the
reception of a specific radio station from a
specific position.
NOTE: Multipath noise and fading noise: Because
the frequency of FM waves is extremely high, it is
highly susceptible to effects from geological
formations and buildings. These effects disrupt the
broadcast signal and obstruct reception in several
ways.
.
•
Multipath noise
This describes the echo that occurs when the
broadcast signal is reflected by a large
obstruction and enters the receiver with a slight
time delay relative to the direct signal (repetitious
buzzing).
•
Fading noise
This is a buzzing noise that occurs when the
broadcast beam is disrupted by obstructing
objects and the signal strength fluctuates
intricately within a narrow range.
Q: Is the problem limited to the reception of a specific
radio station from a specific position?
YES :
Go to Step 5.
NO :
Check that a poor reception is resolved.
STEP 5. Check that the antenna plug is
connected to the radio properly.
Q: Is the antenna plug connected to the radio
properly?
YES :
Go to Step 6.
NO :
Reconnect the antenna plug and radio unit
properly. Check that a poor reception is
resolved.
STEP 6. Check that the problem disappears when
another radio is used.
Q: Does the problem disappear if another radio is
used?
YES :
Repair or replace the radio. Check that a
poor reception is resolved.
Inspection Procedure 16: Distortion on AM or on both AM and FM.
DIAGNOSIS
STEP 1. Check how much distortion there is.
Q: How much distortion is there?
Occasional distortion :
Go to Step 2.
Constant distortion :
Go to Step 3.
STEP 2. Check that there is distortion near the
radio station.
Q: Is there distortion near the radio station?
YES :
The antenna may receive too strong signal.
NO :
Go to Step 3 .
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CHASSIS ELECTRICAL
RADIO WITH TAPE PLAYER AND CD PLAYER
54A-136
STEP 3. Check that the speaker cords are in
contact with the cone paper.
Q: Are the speaker cords in contact with the cone
paper?
YES :
Move the cords away from the cone paper.
Check that a distortion is resolved.
NO :
Go to Step 4.
STEP 4. Remove the speakers, and check for
cone paper or foreign material.
Q: Is there cone paper or foreign material?
YES :
Repair or replace the speakers. Check that
a distortion is resolved.
NO :
Go to Step 5.
STEP 5. Check for distortion with the speaker
installed.
Q: Does a distortion occur?
YES :
Install the speaker securely. Check that a
distortion is resolved.
NO :
Repair or replace the radio. Check that a
distortion is resolved.
Inspection Procedure 17: Distortion on FM only.
DIAGNOSIS
STEP 1. Check that the distortion persists when
the radio is turned to another station.
Q: Does the distortion persist when the radio is
turned to another station?
YES :
Go to Step 2.
NO :
The signal from that station is too weak.
STEP 2. Check that the distortion increases or
decreases when the vehicle is moved.
Q: Does distortion increase or decrease when the
vehicle is moved?
YES :
The cause may be multipath noise.
NO :
Repair or replace the radio. Check that a
distortion is resolved.
Inspection Procedure 18: Using the auto select function, too few automatic stations are selected.
DIAGNOSIS
STEP 1. Consider the number of radio stations.
Check that there are enough radio stations in the
area.
Q: Consider the number of radio stations. Are there
enough in the area?
YES :
Go to Step 2.
NO :
Confirm automatic selection selects the
strongest signals in the area. If not, go to
Step 3.
STEP 2. Consider the distance to the radio
stations. Check that the transmitting antennas
are within 2miles.
Q: Consider the distance to the radio stations. Are the
transmitting antennas within 2 miles?
YES :
Go to Step 3.
NO :
Confirm automatic selection selects the
strongest signals in the area. If not, go to
Step 4.
STEP 3. Make sure that the check is being
conducted under special electrical field
conditions.
Q: Is the check being conducted under special
electrical field conditions (such as in an
underground garage or inside a building)?
YES :
Go to Step 4.
NO :
Go to Step 5.
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