MITSUBISHI TRITON 1997 Workshop Manual

CHASSIS ELECTRICAL ± Radio and Tape Player54-62
ItemsProblem symptomRelevant chart
Tape playerCassette tape will not be inserted.C-1
No sound.C-2
No sound from one speaker.C-3
Sound quality is poor, or sound is weak.C-4
Cassette tape will not be ejected.C-5
Uneven revolution. Tape speed is fast or slow.C-6
Faulty auto reverse.C-7
Tape gets caught in mechanism.C-8
CHART
A. NOISE
A-1 Noise appears at certain places when travelling (AM).
Is there a particular structure?NoDo the following measures eliminate the
noise?
1. Change to a different station with
a strong signal to boost resistance
to interference.
2. Suppress high tones to reduce
noise.
3. Extend antenna completely.Ye sOK
Ye s
Find out the following information from
the user:
1. Place
2. Locality conditions (valley, moun-
tain, etc.)
3. Name and frequency of stations
affected by noiseNo
If due to vehicle noise:
It may not be possible to prevent noise
if the signal is weak.
If there is more noise than other radios, find out the noise
conditions and the name and frequency of the receiving
stations from the user, and consult with the service centre.
If due to external noise:
In almost all cases, prevention on the
receiver side is impossible. Weak sig-
nals especially are susceptible to inter-
ference.

O
K N
o I
f th ere is m ore n ois e th an o th er r a dio s, fin d o ut t h e n ois e c o ndit io ns
a nd th e n am e a nd fr e quency o f th e r e ce iv in g s ta tio ns fr o m th e
u se r, a nd c o nsu lt w it h th e s e rv ic e c e ntr e .
N O TE
A bout F M w ave s:
F M w ave s h ave th e s a m e p ro pertie s a s lig ht, a nd
c a n b e d efle cte d a nd b lo cke d. W ave r e ce ptio n is
n ot p ossib le in th e s h adow o f o bstr u ctio ns s u ch
a s b uild in gs o r m ounta in s.
1 . The s ig nal b eco m es w eak a s th e d is ta nce fr o m
t h e s ta tio n's tr a nsm is sio n a nte nna in cre ase s.
A lt h ough th is m ay v a ry a cco rd in g to th e s ig nal
s tr e ngth o f th e tr a nsm it tin g s ta tio n a nd
i n te rv e nin g g eogra phic a l fo rm atio n o r b uild in gs,
t h e a re a o f g ood r e ce ptio n is a ppro x. 2 0 ± 25
k m fo r s te re o r e ce ptio n, a nd 3 0 ± 40 k m fo r
m onaura l r e ce ptio n.
2 . The s ig nal b eco m es w eak w hen a n a re a o f
s h adow fr o m th e tr a nsm it tin g a nte nna ( p la ce s
w here th ere a re o bstr u ctio ns s u ch a s m ounta in s
o r b uild in gs b etw een th e a nte nna a nd th e c a r),
a nd n ois e w ill a ppear. < T his is c a lle d fir s t fa din g,
a nd g iv e s a s te ady b uzzin g n ois e .> 3
. If a d ir e ct s ig nal h it s th e a nte nna a t th e s a m e
t im e a s a s ig nal r e fle cte d b y o bstr u ctio ns s u ch
a s m ounta in s o r b uild in gs, in te rfe re nce o f th e
t w o s ig nals w ill g enera te n ois e . D urin g
t r a ve llin g, n ois e w ill a ppear e ach tim e th e
v e hic le 's a nte nna p asse s th ro ugh th is k in d o f
o bstr u cte d a re a. T he s tr e ngth a nd in te rv a l o f
t h e n ois e v a rie s a cco rd in g to th e s ig nal s tr e ngth
a nd th e c o ndit io ns o f d efle ctio n. < T his is c a lle d
m ult ip ath n ois e , a nd is a r e petit io us b uzzin g.>
4 . Sin ce F M s te re o tr a nsm is sio n a nd r e ce ptio n
h as a w eake r fie ld th an m onaura l, it is o fte n
a cco m panie d b y a h is sin g n ois e .

CHASSIS ELECTRICAL ± Radio and Tape Player54-64
A-3 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 a different station or the
appearance of a beating sound* may occur.
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 by electrical
waves as well.
2. Factors due to vehicle noise: Alternator noise
may be a cause.
Is the noise still obvious even with the
lamps OFF?No
Ye s
Do the following measures eliminate the
noise?

Tune to a station with a strong signal.

Tune to a station with a strong signal
without completely extending the
antenna.Ye sOK
No
Does the noise fade away when the
vehicle harness is moved away from
the radio chassis? (if the harness is not
in the proper position.)Ye sOK
No
If there is more noise than other radios, consult a service
centre.

CHASSIS ELECTRICAL ± Radio and Tape Player54-65
A-4 Broadcasts can be heard but both AM and FM have a lot of noise.
(1)(2)
Noise occurs when the engine is stopped.
Ye s
Do the following measures eliminate the noise?

Tune to a station with a strong signal.

Extend the antenna completely.

Adjust the sound quality to suppress high tones.Ye s
OK
No
Is the radio body earth mounted securely?NoSecurely tighten the nuts for the body
earth.
Ye s
Is the antenna plug properly connected to the radio?NoCorrectly attach the antenna plug.
Ye s
Is the antenna itself in good condition or is it properly
mounted?NoClean the antenna plug and earth wire
mounting area. Mount the antenna se-
curely.
Ye s
If there is more noise than other radios, consult a service
centre.
Is the noise eliminated?
NoYe s
OK
Noise occurs when the engine in running.
Inspect the vehicle's noise suppressor. (Refer to A-6.)
NOTE
About noise encountered during FM reception only.
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 characteristicsof FM waves of noise or distortion generated by
typical noise interference (first fading and
multipath). (Refer to A-2.)
as mountainous regions, but this is not due to a
problem with the 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.>

<
4G 63, 4 G 64> (
F ig . 2 ) <
4D 56> C
ondit io ns C
ause R
em edy A
M , F M : Ig ni-
t io n n ois e ( P op-
p in g, s n appin g,
c ra ckin g, b uz-
z in g) O
th er e le ctr ic a l
c o m ponents ± N
ois e m ay a ppear a s e le ctr i-
c a l c o m ponents b eco m e o ld -
e r. R
epair o r r e pla ce e le ctr ic a l
c o m ponents . S
ta tic e le ctr ic it y
( C ra ckin g, c rin -
k lin g) O
ccu rs w hen p arts o r w ir in g
m ove fo r s o m e r e aso n a nd
c o nta ct m eta l p arts o f th e
b ody. R
etu rn p arts o r w ir in g to
t h eir p ro per p osit io n. D
ue to d eta ch m ent fr o m t h e
b ody o f th e fr o nt h ood,
b um pers , e xh aust p ip e a nd
m uff le r, s u sp ensio n, e tc . T
ig hte n th e m ountin g b olt s
s e cu re ly . C ase s w here th e
p ro ble m is n ot e lim in ate d b y
a s in gle r e sp onse to o ne
a re a a re c o m mon, d ue to
s e ve ra l b ody p arts b ein g
i m perfe ctly e arth ed.

<
2W D> <
4W D> <
4G 63, 4 G 64> <
V eh ic le s w it h a ir c o ndit io ner> E
nsu re p ro per c o nnectio n. Y
es D
oes n ois e a ppear w hen th e r a dio s w it c h is tu rn ed o n w hile th e
v e hic le is s to pped a nd th e r a dio is s tr u ck w hile t u ned a w ay f r o m
a s ta tio n? N
o S
ta tic e le ctr ic it y n ois e :
B ody s ta tic e le ctr ic fr o m th e s h ock a bso rb er r u bber b ush in gs u se d
t o p re ve nt v ib ra tio n, ty re s, e tc . o ccu rs b eca use o f s e para tio n fr o m
t h e e arth , c a usin g a b uzzin g n ois e . S in ce n o m easu re s c a n b e
t a ke n o n th e r a dio s id e, o th er s te ps s h ould b e ta ke n to d is ch arg e
t h e s ta tic e le ctr ic it y o f th e v e hic le b ody. Y
es I
s th e r a dio c o rre ctly e arth ed? ( Is th e m ountin g s cre w tig hte ned
s e cu re ly ? ) N
o T
ig hte n th e s cre w s e cu re ly . Y
es I
s th e a nte nna c o rre ctly e arth ed? ( If n ois e a ppears w hen th e a nte nna
i s m ove d, th is m eans th e e arth is n ot s e cu re ly c o nnecte d.) N
o I
f r u st is p re se nt a t th e a nte nna e arth s cre w , c le an a nd tig hte n
t h e e arth s e cu re ly . Y
es R
epair o r r e pla ce r a dio .

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.