LEXUS SC400 1991 Service Repair Manual

2CLOCK LOSES OR GAINS TIME
(a) Check that the battery voltage is 10±16 V.
If voltage is not as specified, replace the battery.
(b) Inspect the error of the clock.
Allowable error (par day): + 2.0 seconds
If the error exceeds the allowable error, replace the clock.
(c) Check if the clock adjusting button is sticking in position
and has failed to return.
If the button has not returned, repair or replace the clock.
(d) troubleshoot the clock as follows.
HINT: Inspect the connector on the wire harness side.
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BODY ELECTRICAL SYSTEM ClockBE±195
Is there 10 ± 16 V between terminal +B and
body ground?
Adjust or replace clock. Locate cause, and repair or recharge
battery.
Below 10 V
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AUDIO SYSTEM
System Description
RADIO WAVE BAND
The radio wave bands used in radio broadcasting are as follows:
Frequency 30 kHz300 kHz 3 MHz30 MHz300 MHz
DesignationLFMFHFVHF
Radio waveAM
eFM
e
Modulation methodAmplitude modulationFrequency modulation
LF: Low Frequency MF: Medium Frequency HF: High Frequency VH\
F: Very High Frequency
SERVICE AREA
There are great differences in the size of the service area for
AM, FM monaural, and FM stereo broadcasting. Thus it may
happen that FM broadcasts cannot be received even though
AM comes in very clearly.
Not only does FM stereo have the smallest service area, but
it also picks up static and other types of interference (ºnoiseº)
easily.
RECEPTION PROBLEMS
Besides the problem of static, there are also the problems
called ºfadingº, ºmultipathº and ºfade outº. These pro\
blems
are caused not by electrical noise but by the nature of the ra-
dio waves themselves.
Fading
Besides electrical interference, AM broadcasts are also sus-
ceptible to other types of interference, especially at night.
This is because AM radio waves bounce off the ionosphere
at night. These radio waves then interfere with the signals
from the same transmitter that reach the vehicle's antenna di-
rectly. This type of interference is called ºfadingº.
Multipath
One type of interference caused by the bouncing of radio
waves off of obstructions is called ºmultipathº. Multipath oc-
curs when a signal from the broadcast transmitter antenna
bounces off of buildings and mountains and interferes with
the signal that is received directly.
Fade Out
Because FM radio waves are of higher frequencies than AM
radio waves, they bounce off of buildings, mountains, and
other obstructions. For this reason, FM si gnals often seem to
gradually disappear or fade away as the vehicle goes behind
a building or other obstruction. This is called ºfade outº.
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BODY ELECTRICAL SYSTEM Audio System
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MAINTENANCE OF TAPE PLAYER
Head Cleaning
Using a moist±type cleaning tape, clean the head surface, pinch rolle\
rs and capstans.
COMPACT DISC PLAYER
Compact Disc (hereafter called ºCDº) players use a laser beam pick±up\
to read the digital signals recorded
on the CD and reproduce analog signals of the music, etc. There are 4.7 in\
. (12 cm) and 3.2 in. (8 cm) CD
available, but it is recommended that you do not use 3.2 in. (8 cm) discs in the\
CD auto changer.
HINT: Never attempt to disassemble or oil any part of the player unit. Do not\
insert any object other than
a disc into the magagine.
NOTICE: CD players use on invisible laser laser beam which could cause hazardou\
s radiation expo-
sure. Be sure to operate the player correctly as instructed.
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BODY ELECTRICAL SYSTEM Audio SystemBE±197
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Parts Location
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BODY ELECTRICAL SYSTEM Audio System
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Wiring and Connector Diagrams
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BODY ELECTRICAL SYSTEM Audio SystemBE±199
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BE±200±
BODY ELECTRICAL SYSTEM Audio System
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Wiring and Connector Diagrams
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BODY ELECTRICAL SYSTEM Audio SystemBE±201
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BE±202±
BODY ELECTRICAL SYSTEM Audio System
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Wiring and Connector Diagrams
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BODY ELECTRICAL SYSTEM Audio SystemBE±203
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BE±204±
BODY ELECTRICAL SYSTEM Audio System
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