MITSUBISHI 3000GT 1992 2.G Workshop Manual

Downloaded from www.Manualslib.com manuals search engine CHASSIS ELECTRICAL - Radio and Tape Player54-165
NOISE SUPPRESSION PARTS MOUNTING POSITIONS
1/ Noise con::;;, 1
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Downloaded from www.Manualslib.com manuals search engine 54-166CHASSlS ELECTRICAL - Radio and Tape Player
IA-7Some noise appears when there is vibration or shocks during traveling.
‘d ~
Are connectors properly connected?
YesNo
---+ Ensure proper connection
t
Does noise appear when the radio switch is turned on while theNovehicle is stopped and the radio is struck while tuned away fromLa station?
YesStatic electricity noise:
Body static electric from the shock absorber rubber bushings used
to prevent vibration, tires, etc. occurs because of separation fromthe ground, causing a buzzing noise.
Since no measures can be taken on the radio side, steps shouldbe taken to discharge the static electricitv of the vehicle bodv.
tIs the radio correctly grounded?
(Is the mounting screw tightened securely?)
1 Yes
tIs the antenna correctly grounded? (If noise appears when the Nocantenna is moved, this means the ground is not securely con-
nected.)
If rust is present on the antenna ground screw, clean and tightenthe ground securely.
Yes
1 Reoair or reolace radio.1
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Downloaded from www.Manualslib.com manuals search engine CHASSIS ELECTRICAL - Radio and Tape Player54-167
A-8Noise sometimes appears on FM during traveling.
NoIs the antenna completely extended?
Yes
t Check the antenna itself.
(Refer to E-l, 2.)
+Does the problem clear up whenre
1 No
Yes
iDoes the problem appear only in certain locations and only with yes
certain stations?
No
~ Due to electrical field conditions. (Multipath
noise*, fading noise*).
Are connectors property connected?
Yes
Check connector connections.1
tDoes noise appear when the radio switch is turned on while the
vehicle is stopped
and the radio is struck while tuned away froma station?
Yes
No*Static electricity noise:Sody static electric from the shock absorberrubber bushings used to prevent vibration, tires,etc. occurs because of separation from the
ground, causing a buzzing noise.
Since no measures can be taken on the radioside, steps should be taken to discharge the
static
electricitv of the vehicle bodv.
Is the radio body correctly grounded?
No(Is the mounting screw tightened securely?
)
Yes
-) Tighten the screw securely.I
Is the antenna correctly grounded? (If noise appears when the antennais moved, this means the ground is not securely connected.)
Yes
If rust is present on the antenna ground screw,clean and tighten the ground securely.
*
1 Repair or replace radio.1
About multipath noise and fading noise
Because the frequency of FM waves is extreme-
ly high, it is highly susceptible to effects from
geological formations and buildings. These ef-
fects disrupt the broadcast signal and obstruct
‘reception in several ways.l Multipath noise
This describes the echo that occurs when the
broadcast signal is reflected by a large obstruc-
tion and enters the receiver with a slight time
delay relative to the direct signal (repetitious
buzzing).l Fading noise
This is a buzzing noise that occurs when the
broadcast beam is disrupted by obstructing ob-
jects and the signal strength fluctuates intricately
within a narrow range.
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Downloaded from www.Manualslib.com manuals search engine 54-168CHASSIS ELECTRICAL - Radio and Tape Player
IA-9Ever-present noise.I
Noise is often created by the following factors, and
often the radio is OK when it is checked individually.l Traveling conditions of the vehicle
l Terrain of area traveled through
l Surrounding buildings
l Signal conditions
l Time periodFor this reason, if there are still problems with noiseeven after the measures described in steps A-l
to A-8 have been taken, get information on the fac-
tors listed above as well as determining whetherthe problem occurs with AM or FM, the station
names, frequencies, etc., and contact a service cen-
ter.B. RADIO
IB-lNo power is supplied when the switch is set to ON.IIIIs multi-purpose fuse No. 4 blown or is the circuit open?Replace fuse or repair harness.
NoIs the connector at the back of the radio connected properly?
Yes
Connect connector securely.1t
NoDisconnect and check the connector at the rear of the radio. Is the ACC / Repair harness.
power (12 V) being supplied to the radio?J
I
Yes
1 Reoair or reolace radio.
1 B-2No sound from one speaker.ICheck to see if there is any sound when attached
to another radio.
I-=----[Repair or replace radio unit.
No
checkthespeakerharnessfor conductance.
out.*Speakarj
NoRepair speaker harness and ensure
proper connection of relay connectors.
tRepair or replace speaker.
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There is noise but no reception for both AM and FM or no sound from AM, or no sound from FM.
Example: in an underground garage or
Is proper performance
hicle is moved?
tt
Is the antenna completely extended?
YesNo
Check the antenna itself.-W (Refer to E-l, 2.)
Does tuning solve the problem?
Yes
NO
tNoAre the antenna plug and radio unit properly connected?
Yes
- Reconnect1Does the problem disappear if connected to another radio?
No
Repair or replace radio.1t
Repair or replace the antenna.
(Refer to E-l, 2.)
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Is proper performance’obtained when the ve-pziT---wm
4tIs the antenna completely extended?
YesNoCheck the antenna itself.
(Refer to E-l, 2.)
t
NoYes
Is the problem limited to the reception of a specific radio station yes)Electrical field condition related*.from a specific position?(multipath noise or fading noise)
No
iIs the antenna plug properly connected to the unit?
Yes
Ensure proper connection.Does the problem disappear when a different radio is connected?Repair or replace radio.
Repair or replace the antenna.
(Refer to E-l, 2.)
*For multipath noise and fading noise prob-
lems, refer to P.64-167.
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Downloaded from www.Manualslib.com manuals search engine CHASSIS ELECTRICAL - Radio and Tape Player54-I 71
1 B-5Distortion on AM or on both AM and FM.Are the speaker cords in contact with the cone paper?
NoRemove cords away from cone
pa-per.Remove the speakers and check for tom cone paper or foreign objects.
INoRepair or replace speakers.
iCheck for deformation with speaker installed.
No
Yes- Install speaker securely.
\ Repair or replace radio.j
B-6Distortion on FM onlyDoes the distortion persist when the radio is tuned to another
Nostation?
Yes
)- Due to weak electrical field of radiostation
YesDoes distortion increase or decrease when the vehicle is moved? ,
/ NoDue to multipath noise
1
1Repair or replace radio.
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Downloaded from www.Manualslib.com manuals search engine 54-172CHASSIS ELECTRICAL - Radio and Tape Player
B-7Too few automatic select stations.
tIs the antenna completely extended?
YesNo1Check theantennaitself.Is the antenna plug properly connected to the equipment?
Yes
Ensure proper connection.Does the equipment work properly if the radio is changed?
Repair or replace radio.
B-8lnsuff icient memory (preset stations are erased).Is multi-purpose fuse No. 19 blown or is the circuit open?
NoReplace fuse or repair harness.
Disconnect and check the connector at the rear of the radio. Is the memory
backup (battery) power beina supplied?Repair harness..-IYes
tRepair or replace radio.
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Downloaded from www.Manualslib.com manuals search engine CHASSIS ELECTRICAL - Radio and Tape Player54-173C. CASSETTE PLAYER
C-lCassette tape will not be inserted.Are there any foreign objects in the cassette player?/NoRemove the object(s)”
“1Attempting to force a foreign object (e g.. a coin or clip, etc.) out
of the cassette player may damage the mechanism. The player
should be taken to a service dealer for repair.
Does the cassette player work if another tape is inserted?
NoReplace tape
**
*2Ensure that the tape label is not that the tape itself tape of C-120
or greater length often get caught in the mechanism and should
not be used.
Repair or replace cassette player.
C-2No sound (even after a tape has been inserted).Is multi-purpose fuse No. 4 blown or is the circuit open?
NoYes
- Replace fuse or repair harness.
+Is connector at rear of radio connected tightly?
YesNo
- Connect connector firmly.
Disconnect connector at rear of radio. Is ACC power being supplied to the
yesPW Repair or replace caSSette player.
radio?
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CHASSIS ELECTRICAL - Radio and Tape Player
C-3No sound from one speaker.t
YesReplace the cassette player and check again.
NoRepair or replace cassette player.
thespeaker harness for conductance.___c It conducts electricity but isshorted out.
+Check the speaker for conductance.
NoRepair speaker harness and ensureproper connection of relay connectors.
tRepair or replace speaker.
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