Mitsubishi 380. Manual - part 918

 

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Mitsubishi 380. Manual - part 918

 

 

RADIO WITH CD PLAYER

CHASSIS ELECTRICAL

54A-206

STEP 19. Check the wiring harness between rear speaker 
(RH) connector D-09 (terminals 1 and 2) and radio and CD 
player connector C-111 (terminals 1 and 7).

NOTE: Also check intermediate connector C-28 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the 
connector. If intermediate connector C-28 is damaged, repair or 
replace the connectors as described in GROUP 00E, Harness 
Connector Inspection 

P.00E-2

.

Q: Is the wiring harness between rear speaker (RH) 

connector D-09 (terminals 1 and 2) and radio and CD 
player connector C-111 (terminals 1 and 7) in good 
condition?
YES : 
Replace the radio and CD player. The rear speaker 

(RH) should sound.

NO :  Repair the wiring harness. The rear speaker (RH) 

should sound.

54DB041A

HARNESS SIDE

3

9

4

12

14

6

13

5

1110

8

2

7

1

CONNECTOR: C-111

16DB350A

CONNECTOR:C-28

16DB608A

CONNECTOR: D-09

HARNESS SIDE

RADIO WITH CD PLAYER

CHASSIS ELECTRICAL

54A-207

INSPECTION PROCEDURE 6: Noise is Present while Moving (AM).

STEP 1. Ask the driver about 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: What type of noise is detected, vehicle noise or 

external noise?
Vehicle noise : 

It may not be possible to prevent 

noise if the signal is weak. Go to step 2.

External noise : 

In almost all cases, prevention on 

the receiver side is next to impossible when 
the signal is weak. Go to Step 4.

STEP 2. Ask the driver about the location where 
the noise occurs.

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 4.

STEP 3. Check if the noise can be eliminated by 
adjusting the radio.
(1) Adjust the radio as follows.
(2) Change to a different station with a stronger 

signal. This will boost the systems resistance to 
outside interference.

(3) Suppress high tones to reduce noise.

Q: Has the noise been eliminated?

YES : 

The noise has now been eliminated. Inform 

the customer that it is normal to hear noise 
while receiving a weak station.

NO : 

Go to Step 4.

STEP 4. Check for the noise.

Q: Does noise still exist? 

YES : 

If there is still more noise than on other 

similar radio’s find out the type of noise. Ask 
the owner for the name and frequency of the 
affected stations, and consult with the radio 
manufacturer service centre.

NO : 

System is operating normally.

INSPECTION PROCEDURE 7: Noise is Present while Moving (FM).

.

DIAGNOSIS

NOTE: FM waves have the same properties as light, 
and can be deflected and blocked. FM signal recep-
tion is severely degraded in the shadow of obstruc-
tions such as buildings or mountains. An FM receiver 
will then only receive a reflected signal.

1. The signal becomes weak as the distance from 

the station's transmission antenna increases. The 
signal strength received depends on the signal 
strength of the transmitting station and intervening 
obstructions such as buildings and hills. Generally 
speaking, the area of good reception is 
approximately 20 

− 25 km  for stereo reception, 

and 30 

− 40 km  for monaural reception.

2. The signal will 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.>

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

RADIO WITH CD PLAYER

CHASSIS ELECTRICAL

54A-208

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. When moving, 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. Does vehicle have an antenna which extend? If 

not eliminate this step.

If there is noise, the following causes can be consid-
ered.
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 not possible. 
Weak signals especially are susceptible to 
interference.

If there is more noise than on radios in other vehi-
cles, 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 
centre.

INSPECTION PROCEDURE 8: Sound mixed with Noise, Only at Night (AM).

The following can be considered as possible causes 
of noise appearing only at night.
1. It is significantly easier to receive long-distance 

signals at night. This means that even stations 
that are received without a problem during the day 
may experience problems at night. Remember 
that the weaker station is more susceptible to 
interference. The appearance of a beat sound 
may occur in the evening. A beat sound is created 
when two signals close in frequency interfere with 
each other. A common sign of this type of 
interference is a repetitious high-pitched sound 
that may over power the desired radio station. 
This sound is generated not only by sound signals 
but electrical waves as well.

2. The changing system may also be a source of 

noise. When diagnosing radio noise, do not over 
look the possibility of a problem with the vehicles 
alternator.

DIAGNOSIS

STEP 1. Check the vehicles lighting system.

Q: Does the noise disappear when the vehicles 

headlamps are turned "OFF"?
YES : 

Go to Step 2.

NO : 

Go to Step 3.

STEP 2. Check that the following actions 
disappear the noise.
Tune to a station with a stronger signal.

Q: Is there more noise than on radio in other 

vehicles?
YES : 

Consult the radio manufacturer's service 

centre.

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)?
YES : 

Consult the radio manufacturer's service 

centre.

NO : 

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

RADIO WITH CD PLAYER

CHASSIS ELECTRICAL

54A-209

INSPECTION PROCEDURE 9: Noise is Overpowering both AM and FM.

DIAGNOSIS

STEP 1. Verify that the noise occur when the 
engine is stopped or the engine is running.

Q: Does noise occur when the engine is stopped or 

the engine is running?
When the engine is stopped : 

Go to Step 2.

When the engine is running : 

Check the vehicle's 

noise suppressor. (Refer to Inspection 
Procedure 13 

P.54A-210

).

STEP 2. Verify that the following actions 
disappear the noise.
(1) Tune to a station with a stronger wave.
(2) Adjust the sound quality to suppress high tones.

Q: Is the noise eliminated?

YES : 

Consult the radio manufacturer's service 

centre.

NO : 

Go to Step 3.

STEP 3. Verify that the radio is correctly 
grounded

Q: Is the radio correctly grounded?

YES : 

Go to Step 4.

NO : 

Consult the radio manufacturer's service 
centre.

STEP 4. Check the connection of the antenna 
plug and radio and CD player or radio, CD player 
and CD changer.

Q:  Is the antenna plug thoroughly connected to the 

radio and CD player or radio, CD player and CD 
changer?
YES : 

Go to Step 6.

NO : 

Go to Step 5.

STEP 5. Verify that the noise is eliminated when 
the antenna plug is properly attached.

Q: Is the noise eliminated?

YES : 

Consult the radio manufacturer's service 

centre.

NO : 

Go to Step 6.

STEP 6. Verify that the antenna is in good 
condition and is it properly mounted.

Q: Is the antenna in good condition and is it properly 

mounted?
YES : 

Consult the radio manufacturer's service 

centre.

NO : 

Go to Step 7.

STEP 7. Clean the antenna plug and ground wire 
mounting area. Mount the antenna securely.

NOTE: Noise encountered during FM reception only 
due to differences in FM and AM system, FM is not 
as susceptible as AM to interference from engines, 
power lines, lighting, etc. On the other hand, due to 
the characteristics of FM waves, there are some-
times cases of noise or distortion which are gener-
ated by typical noise interference (first fading and 
multipath). (Refer to Inspection Procedure 9 

P.54A-207

.) <Noise (hissing) occurs in weak signal 

areas such as mountainous regions, but this is not 
due to a problem with the radio.>

NOTE: Furthermore, the amount of interference will 
be comparatively less for vehicles equipped with a 
diversity antenna system*. If there is an equivalent 
amount of distortion in vehicles or radios of the same 
type, then differences will be because of differences 
in antenna systems, and this should be explained to 
the user.

NOTE: Diversity antenna system*: A system where 
two types of antenna (glass main antenna and glass 
sub antenna) are equipped and the antenna that pro-
vides the best reception car be selected.

Q: Is the antenna in good condition?

YES : 

Consult the radio manufacturer's service 

centre.

NO : 

Clean or repair it. Check the noise is 
eliminated. If the noise is not eliminated, 
consult the radio manufacturer's service 
centre.

 

 

 

 

 

 

 

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