Lexus SC300 / Lexus SC400. Manual — part 146

2

CLOCK 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

Clock

BE–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

AUDIO SYSTEM

System Description

RADIO WAVE BAND

The radio wave bands used in radio broadcasting are as follows:

Frequency

30 kHz

300 kHz

3 MHz

30 MHz

300 MHz

Designation

LF

MF

HF

VHF

Radio wave

AM

↔

FM

↔

Modulation method

Amplitude modulation

Frequency modulation

LF: Low Frequency MF: Medium Frequency HF: High Frequency VHF: 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 (”noise”)
easily.

RECEPTION PROBLEMS

Besides the problem of static, there are also the problems
called ”fading”, ”multipath” and ”fade out”. These problems
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 ”fading”.

Multipath

One type of interference caused by the bouncing of radio
waves off of obstructions is called ”multipath”. 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 signals often seem to
gradually disappear or fade away as the vehicle goes behind
a building or other obstruction. This is called ”fade out”.

BE–196

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BODY ELECTRICAL SYSTEM

Audio System

MAINTENANCE OF TAPE PLAYER

Head Cleaning
Using a moist–type cleaning tape, clean the head surface, pinch rollers and capstans.

COMPACT DISC PLAYER

Compact Disc (hereafter called ”CD”) 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 hazardous radiation expo-
sure. Be sure to operate the player correctly as instructed.

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BODY ELECTRICAL SYSTEM

Audio System

BE–197

Parts Location

BE–198

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BODY ELECTRICAL SYSTEM

Audio System