Lexus SC300 / Lexus SC400. Manual - part 154

Temporarily install another amplifier.
Functions is OK?

Power amplifier faulty.

Radio receiver assembly faulty.

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM

BE–227

5

Radio

VOLUME FAINT (EXCEPT WOOFER)

A. without CD player type

*Is there continuity between the following terminals
with connector disconnected?

 Radio receiver assembly D3–ground

Is tape player operating normally?

Radio receiver assembly faulty.

Power switch faulty.

Wire harness faulty.

Radio receiver assembly faulty.

When the volume switch is turned from minimum
to maximum, does resistance between terminals
B1–B3 of radio receiver assembly change from 0
to 50 k



?

B. with CD player type

*Is there continuity between the following terminals
with connector disconnected?

 Radio receiver assembly D3–ground

Is tape player operating normally?

Radio receiver assembly faulty.

Power switch faulty.

Wire harness faulty.

Radio receiver assembly faulty.

When the volume switch is turned from minimum
to maximum, does resistance between terminals
B1–B3 of radio receiver assembly change from 0
to 50 k



?

Power amplifier faulty.

Temporarily install another power amplifier
Function is OK?

BE–228

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM

6

Radio

WOOFER DOES NOT WORK

A. without CD player type

Is there battery voltage between the following termi-
nals with connector connected?

 Woofer amplifier 3 – ground

 Woofer amplifier 4 – ground

Is there continuity between the following terminals
with connector disconnected?

 Woofer amplifier 9 – Woofer 2

 Woofer amplifier 10 – Woofer 1

Is there continuity between the following terminals
with connector disconnected?

 Woofer amplifier 9 – ground

 Woofer amplifier 10 – ground

Is there continuity between the following termi-
nals with connector connected?

 Radio receiver assembly A9–Woofer amplifier 6

Wire harness faulty.

Wire harness faulty.

Wire harness faulty.

Wire harness faulty.

Woofer faulty.

Is there continuity between the following termi-
nals with connector disconnected?

 Woofer amplifier 7–ground

Is there battery positive between the following
terminals with connector connected?

 Woofer amplifier 7–ground

Temporarily install another woofer.
Functions OK?

Radio receiver assembv faulty.

Radio receiver assembly faulty.

Is tape player operating normally?

Radio receiver
assembly faulty.

Wire harness faulty.

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM

BE–229

B. with CD player type

HINT: The part names and terminals indicated in brackets ( ) are for models with a Nakamichi system.

Wire harness faulty.

Wire harness faulty.

Wire harness faulty.

Wire harness faulty.

Wire harness faulty.

Woofer faulty.

Radio receiver assembly faulty.

Is tape player operating normally?

Radio receiver assembly faulty.

Temporarily install another woofer.
Functions OK?

Is there battery voltage between the following ter-
minals with connector connected?

 Woofer amplifier 6 (Power amplifier C6) – ground

Is there continuity between the following terminals
with connector disconnected?

Woofer amplifier 9 (Power amplifier C9) –Woofer 2

Woofer amplifier10 (Power amplifier C10) –Woofer 1

Is there continuity between the following terminals
with connector disconnected?

Woofer amplifier 7 (Power amplifier C7) –ground

Is there continuity between the following terminals
with connector disconnected?

Woofer amplifier 9 (Power amplifier C9) –ground

Woofer amplifier10 (Power amplifier C10) –ground

Is there battery positive between the following
terminals with connector connected?

Woofer amplifier 3 (Power amplifier C3) –ground

Woofer amplifier4 (Power amplifier C4) –ground

BE–230

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM