Mitsubishi Galant. Manual — part 643

RADIO WITH TAPE PLAYER AND CD PLAYER

TSB Revision

CHASSIS ELECTRICAL

54A-125

STEP 2. Check the radio, tape player and CD player
connector C-31 and vehicle speed sensor connector B-35
for damage.
Q: Are radio, tape player and CD player connector C-31

and vehicle speed sensor connector B-35 in good
condition?
YES : Go to Step 4 .
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. The sound volume

should depend on vehicle speed.

AC003686

CONNECTOR: B-35
<2.4L ENGINE>

AB

AC003687

CONNECTOR: B-35
<3.0L ENGINE>

AB

AC003089

CONNECTOR: C-31

AT

TSB Revision

CHASSIS ELECTRICAL

RADIO WITH TAPE PLAYER AND CD PLAYER

54A-126

STEP 3. Check the harness wires between radio, tape
player and CD player connector C-31 and vehicle speed
sensor connector B-35.
NOTE: After inspecting intermediate connector C-17 and C-56,
inspect the wires. If intermediate connector C-17 and C-56 are
damaged, repair or replace them. Refer to GROUP 00E,
Harness Connector Inspection

P.00E-2

.

Q: Are the harness wires between radio, tape player and

CD player connector C-31 and vehicle speed sensor
connector B-35 in good condition?
YES : Repair or replace the radio, tape player and CD

player. The sound volume should depend on vehicle
speed.

NO : Repair them. The sound volume should depend on

vehicle speed.

AC003686

CONNECTOR: B-35
<2.4L ENGINE>

AB

AC003687

CONNECTOR: B-35
<3.0L ENGINE>

AB

AC003089

C-17

C-31

CONNECTORS: C-17, C-31

AN

AC003089

CONNECTOR: C-56

AW

RADIO WITH TAPE PLAYER AND CD PLAYER

TSB Revision

CHASSIS ELECTRICAL

54A-127

Inspection Procedure 5: Noise appears at certain places when traveling (AM).

DIAGNOSIS

STEP 1. Check that the noise occur when
entering or near a particular structure (building,
tunnel, mountain, etc).

Q: Does the noise occur when entering or near a

particular structure (building, tunnel, mountain,
etc.)?
YES :

Go to Step 3 .

NO :

Go to Step 2.

STEP 2. After taking the following measures to
prevent the noise, check that no noise appears.
(1) Change to a different station with a stronger

wave to boost resistance to interference.

(2) Suppress high tones to reduce noise.
(3) Extend antenna completely.

Q: Do the following measures eliminate the noise?

YES :

The following causes can be considered.

NO :

Go to Step 4.

STEP 3. Ask the owner about the state of the
noise.
(1) Find out the following information from the owner.
(2) Place where the noise occurs.
(3) Locality conditions (valley, mountain, etc.)
(4) Name and frequency of stations affected by noise

Q: Which is the noise, vehicle noise or external

noise?
Vehicle noise :

It may not be possible to prevent

noise if the signal is weak.

External noise :

In almost all cases, prevention on

the receiver side is impossible. Weak
signals especially are susceptible to
interference. Go to Step 4 .

STEP 4. Check that there is no noise.

Q: Does noise still exist?

YES :

If there is more noise than on radios in other

vehicles, find out the noise condition and
the name and frequency of the receiving
stations from the owner, and consult with
the radio manufacturer's service center.

NO :

Normal

Inspection Procedure 6: Noise appears at certain places when traveling (FM).

DIAGNOSIS

NOTE: About FM waves: FM waves have the same
properties as light, and can be deflected and
blocked. Wave reception is not possible in the
shadow of obstructions such as buildings or
mountains.

1. The signal becomes weak as the distance from

the station's transmission antenna increases. This
may depend on the signal strength of the
transmitting station and intervening geographical
formation of buildings. Generally speaking, the
area of good reception is approximately 20

−

25

km (12

−

16 miles) for stereo reception, and 30

−

40 km (19

−

25 miles) for monaural reception.

ACX01869

10kW
OUTPUT FM
BROAD CAST

FOR STEREO:
20 - 25 km
(12 - 16 miles)

FOR MONAURAL:
30 - 40 km (19 - 25 miles)

FOR HOME STEREO:
80 - 90 km (50 - 56 miles)

MALTIPATH INTERFERENCE

FIRST FADING
INTERFERENCE

AC

TSB Revision

CHASSIS ELECTRICAL

RADIO WITH TAPE PLAYER AND CD PLAYER

54A-128

2. The signal becomes weak when an area of

shadow from the transmitting antenna (places
where there are obstructions such as mountains
or buildings between the station transmitter and
the vehicle), and noise will appear. <This is called
first fading, and gives a steady buzzing noise.>

3. If a direct signal hits the antenna at the same time

as a signal reflected by obstructions such as
mountains or buildings, interference of the two
signals will generate noise. During traveling, noise
will appear each time the vehicle's antenna
passes through this kind of obstructed area. The
strength and interval of the noise varies according
to the signal strength and the conditions of
deflection. <This is called multipath noise, and is a
repetitive buzzing.>

4. Since FM stereo transmission and reception has a

weaker field than monaural, it is often
accompanied by a hissing noise.

After taking measures to prevent the noise, check
that no noise occurs.
5. Change to a different station with a stronger wave

to boost resistance to interference.

6. Suppress high tones to reduce noise.

7. Extend antenna completely.
If there is noise, the following causes can be
considered.
8. If due to vehicle noise: It may not be possible to

prevent noise if the signal is weak.

9. If due to external noise: In almost all cases,

prevention on the receiver side is impossible.
Weak signals especially are susceptible to
interference.

If there is more noise than on radios in other
vehicles, find out the noise condition and the name
and frequency of the receiving stations from the
owner, and consult with the radio manufacturer's
service center.

Inspection Procedure 7: Mixed with noise, only at night (AM).

The following factors can be considered as possible
causes of noise appearing at night.
1. Factors due to signal conditions: Due to the fact

that long-distance signals are more easily
received at night, even stations that are received
without problem during the day may experience
interference in a general worsening of reception
conditions. The weaker a station is the more
susceptible it is to interference, and a change to
different station or the appearance of a beating
sound* may occur.

NOTE: Beat sound*: Two signals close in
frequency interfere with each other, creating a
repetitious high-pitched sound. This sound is
generated not only by sound signals but electrical
waves as well.

2. Factors due to vehicles noise: Generator noise

may be a cause.

DIAGNOSIS

STEP 1. Check that the noise is still obvious even
when the lights are off.

Q: Is the noise still obvious even when the lights are

off?
YES :

Go to Step 2.

NO :

Go to Step 3.

STEP 2. Check that the following actions
disappear the noise.
(1) Tune to a station with a stronger wave.
(2) Tune to a station with a stronger wave without

completely extending the antenna (Whip
antenna).

Q: Is there more noise than on radio in other

vehicles?
YES :

Consult the radio manufacturer's service

center.

NO :

Check that there is no noise.

STEP 3. Check that the noise fades away when
the vehicle harness is moved away from the
radio (if the harness is not in the proper
position).

Q: Does the noise fade away when the vehicle

harness is moved any from the radio (If the
harness is not in the proper position)?
NO :

If there is more noise than other radios,
consult the radio manufacturer's service
center.