1997 MITSUBISHI TRITON radio

CHASSIS ELECTRICAL ± Radio and Tape Player54-66
A-5 There is more noise either on AM or on FM.
1. There is much noise only on AM.
Due to differences in AM and FM systems,
AM is more susceptible to noise interference.
Were conditions such as the following present when noise was
received?

Lightning was flashing. A motorcycle was passing.

A vehicle passed close by, but it appeared to be a vehicle
generating a particularly large amount of noise radiation.

Passed beneath a power line. Passed under a bridge.

Passed beneath a telephone line.

Passed close by a signal generator.

Passed close by some other source of electrical noise.
Ye s
No
Continue to check for static; when static is detected, check for
the conditions listed above.Ye sNoise prevention on the radio side is difficult. If the problem is
particularly worse than other radios, consult a service centre.
No
If the problem is particularly worse than other radios, consult a
service centre.
2. There is much noise only on FM.
Due to differences in FM and AM systems,
FM is not as susceptible as AM to interference
from engines, power lines, lightning, etc. On
the other hand, there are cases due to the
characteristics of FM waves of noise ordistortion generated by typical noise
interference (first fading and multipath). (Refer
to A-2) areas such as mountainous regions, but this
is not due to a problem with the radio.>

CHASSIS ELECTRICAL ± Radio and Tape Player54-69
A-8 Noise sometimes appears on FM during travelling.
Does the problem clear up when retuned?Ye sOK
No
Does the problem appear only in certain locations and only with
certain stations?Ye sDue to electrical field conditions. (Multipath noise*, fading noise*).
Are connectors properly connected?NoCheck connector connections.
Ye s
Does noise appear when the radio switch is turned on while the
vehicle is stopped and the radio is struck while tuned away from
a station?NoStatic electricity noise:
Body static electric from the shock absorber rubber bushings used
to prevent vibration, tyres, etc. occurs because of separation from
the earth, causing a buzzing noise. Since no measures can be
taken on the radio side, other steps should be taken to discharge
the static electricity of the vehicle body.
Ye s
Is the radio body correctly earthed? (Is the mounting screw tightened
securely?)NoTighten the screw securely.
Ye s
Is the antenna correctly earthed? (If noise appears when the antenna
is moved, this means the earth is not securely connected.)NoIf rust is present at the antenna earth screw, clean and tighten
the earth securely.
Ye s
Repair or replace radio.
No
* About 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 largeobstruction 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.

CHASSIS ELECTRICAL ± Radio and Tape Player54-70
A-9 Ever-present noise.
Noise is often created by the following factors, and
often the radio is OK when it is checked individually.

Travelling conditions of the vehicle

Terrain of area travelled through

Surrounding buildings

Signal conditions

Time periodFor this reason, if there are still problems with noise
even after the measures described in steps A-1
to A-8 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 a service
centre.
B. RADIO
B-1 No power is supplied when the switch is set to ON.
Is dedicated fuse No. 4 blown or is the circuit open?Ye sReplace fuse or repair harness.
No
Is the connector at the back of the radio connected properly?NoConnect connector securely.
Ye s
Disconnect and check the connector at the rear of the radio. Is
the ACC power (12 V) being supplied to the radio?NoRepair harness.
Ye s
Repair or replace radio.
B-2 No sound from one speaker.
Check to see if there is any sound when
attached to another radio.Ye sRepair or replace radio.
No
Remove the connector on the back of
the radio and check the speaker harness
for conductance.Ye sIt conducts electricity but is shorted out.Repair speaker harness.
No
Check the speaker for conductance.Ye sRepair speaker harness and ensure
proper connection of relay connectors.
No
Repair or replace speaker.

CHASSIS ELECTRICAL ± Radio and Tape Player54-71
B-3 There is noise but no reception for both AM and FM or no sound from AM, or no sound from
FM.
OK
Is the check being conducted under spe-
cial electrical field conditions?Ye s
Example: In an underground
garage or inside a building.
No
Does tuning solve the problem?
Is proper performance obtained when
the vehicle is moved?Ye s
OKYe s
No
No
ReconnectNoAre the antenna plug and radio unit properly connected?
Ye s
Repair or replace radio.Ye sDoes the problem disappear if connected to another radio?
No
Replace the antenna.
B-4 Insufficient sensitivity.
No
Replace the antenna.
Ye s
Repair or replace radio.Ye sDoes the problem disappear when a different radio is con-
nected?
OK
Is the check being conducted under spe-
cial electrical field conditions?Ye s
Example: In an underground
garage or inside a building.
No
Does tuning solve the problem?
Is proper performance obtained when
the vehicle is moved?Ye s
OKYe s
No
No
Electrical field condition related*
(multipath noise or fading noise)Ye sIs the problem limited to the reception of a specific radio
station from a specific position?
No
Ensure proper connection.NoIs the antenna plug properly connected to the unit?
* For multipath noise and fading noise problems, refer to P. 54-69.

CHASSIS ELECTRICAL ± Radio and Tape Player54-72
B-5 Distortion on AM or on both AM and FM.
How much distortion is there?OccasionalDistortion in the vicinity of the radio sta-
tionYe sExcessive antenna input
Constant
No
Are the speaker cords in contact with the cone paper?Ye sRemove cords away from cone paper.
No
Remove the speakers and check for torn cone paper or foreign
objects.Ye sRepair or replace speakers.
No
Check for deformation with speaker installed.Ye sInstall speaker securely.
No
Repair or replace radio.
B-6 Distortion on FM only
Does the distortion persist when the radio is tuned to another station?NoDue to weak electrical field of radio station
Ye s
Does distortion increase or decrease when the vehicle is moved?Ye sDue to multipath noise
No
Repair or replace radio.
B-7 Too few automatic select stations.
OK
Is the check being conducted under spe-
cial electrical field conditions?Ye s
Example: In an underground
garage or inside a building
No
Is the antenna plug properly connected to the equipment?
Is proper performance obtained when
the vehicle is moved?
Ensure proper connection.No
No
Ye s
Repair or replace radio.Ye sDoes the equipment work properly if the radio is changed?
No
Replace the antenna.Ye s

CHASSIS ELECTRICAL ± Radio and Tape Player54-73
B-8 Insufficient memory (preset stations are erased).
Is dedicated fuse No. 5 blown or is the circuit open?Ye sReplace fuse or repair harness.
No
Disconnect and check the connector at the rear of the radio.
Is the memory backup (battery) power being supplied?NoRepair harness.
Ye s
Repair or replace radio.
C. TAPE PLAYER
C-1 Cassette tape will not be inserted.
Are there any foreign objects in the tape player?Ye sRemove the object(s)*1
No*1
Attempting to force a foreign object (e.g., a coin or clip, etc.) out
of the tape player may damage the mechanism. The player should
be taken to a service dealer for repair.
Does the tape player work if another tape is inserted?Ye sReplace tape*2
No
Repair or replace tape player.
*2
Ensure that the tape label is not loose, that the tape itself is not
deformed and that the tape is tightly wound. Also, tape of C-120
or greater length often get caught in the mechanism and should
not be used.
C-2 No sound (even after a tape has been inserted).
Is dedicated fuse No. 4 blown or is the circuit open?Ye sReplace fuse or repair harness.
No
Is connector at rear of radio connected tightly?NoConnect connector firmly.
Ye s
Disconnect connector at rear of radio. Is ACC power being supplied
to the radio?Ye sRepair or replace tape player.
No
Repair harness.

CHASSIS ELECTRICAL ± Radio and Tape Player54-74
C-3 No sound from one speaker.
Clean the tape player head and check again.Ye sOK
No
Replace the tape player and check again.Ye sRepair or replace tape player.
No
Remove the connector on the back of the radio and check
the speaker harness for conductance.Ye sIt conducts electricity but is
shorted out.Repair harness.
No
Check the speaker for conductance.Ye sRepair harness.
No
Repair or replace speaker.
C-4 Sound quality is poor, or sound is weak.
Does the player play properly when another tape* is inserted?Ye sOK
No
*:

Ensure that the tape label is not loose, that the tape
itself is not deformed and that the tape is tightly wound.

Tapes of C-120 or greater length often get caught in
the mechanism and should not be used.
Does the player play properly when the tape player head is cleaned?Ye sOK
No
Is proper operation obtained when the tape player is replaced?Ye sRepair or replace tape player.
No
Repair or replace speaker.
C-5 Cassette tape will not be ejected.
The problems covered here are all the result of
the use of a bad tape (deformed or not properly
tightened) or of a malfunction of the tape player
itself. Malfunctions involving the tape becoming
caught in the mechanism and ruining the case arealso possible, and attempting to force the tape out
of the player can cause damage to the mechanism.
The player should be taken to a service dealer
for repair.

CHASSIS ELECTRICAL ± Radio and Tape Player54-76
C-8 Tape gets caught in mechanism*1.
*1
When the tape is caught in the mechanism, the case may
not eject. When this occurs, do not try to force the tape
out as this may damage the tape player mechanism. Take
the cassette to a service dealer for repair.
Does the player play OK if the tape*2 is changed?Ye sTape used is bad.
No
*2
Ensure that the tape label is not loose, that the tape itself
is not deformed and that the tape is tightly wound. Also,
tapes of C-120 or greater length often get caught in the
mechanism and should not be used.
Repair or replace tape player.