Kenwood KAC 6402 Service Manual

Page 2

KAC-6402

BLOCK DIAGRAM

ISOLATION

LINE IN
AL 5

LINE IN
AR

AMPLIFIER

ISOLATION
AMPLIFIER

ISOLATION

LINE IN
BL

LINE IN
BR

AMPLIFIER

SPEAKER <
INPUT

AVAB

+6dB

POWER SPEAKER
Ash AMPLIFIER OUT AL
INPUT
GAIN
CONT POWER SPEAKER
sT/MONO AMPLIFIER OUT AR
MUTE
POWER SPEAKER
och AMPLIFIER OUT BL
INPUT
AIN , , ,
CONT HPF 1. POWER SPEAKER
1 I LPF+6dB I AMPLIFIER OUT BR

ISOLATION I
AMPLIFIER , fen/MONO

:15V DC/DC DC DETECT AND
AVR CONVERTER OVER ROAD PROTECTION
, P CON CIRCUIT - P CON
THERMAL -OVER VOLTAGE
PROTECTION PROTECTION BATTERY
OdB

+29.5dB

COMPONENTS DESCRIPTION

0 AUDIO UNIT (X09-5890-10)

Ref. No. Application / Function Operation / Condition / Compatibility
IC1,3 Buffer amplifier Lowers impedance and amplify by 6dB
IC2,4 Isolation amplifier Reduces common mode noise
ICS,9 Buffer amplifier Rch operates as reverse amplifier
ICG,10 Reverse buffer amplifier Reverse amplifier operation of 6dB
|C7,8,11,12 LPF/HPF LPF and HPF with Variable cut off
IC13 DC-DC converter Oscillation and control of DC-DC converter
03,4 Constant voltage power supply Constant voltage control of i15V
05,6 DC-DC converter Switching FET
07,8,9,10 DC-DC converter Gate driver for 05,6
011,12 DC-DC converter ON/OFF of IC13 output
0101,102,201,202 Input mute circuit Shock noise absorption at power ON/OFF
0103~106,203~206 Power amplifier First step differential absorption
0107~110,207~210 Power amplifier Second step differential absorption

0111,112,211,212

Power amplifier

Second step current mirror load

Q113,114,213,214

Power amplifier

Power amplification Circuit bias temperature compensation

0115~118,215~218 Power amplifier Excess current detection

0119~122,219~222 Power amplilier Power amplification step darlington driver

0123~126,223~226 Power amplifier Power amplification step darlington output transistor

0601 B-class step mute Mute signal generation circuit: Normally ON

0602 Mute circuit Mute signal generation circuit: Normally OFF

0603 Input mute Mute signal generation circuit: Normally OFF

0604 Power ON/OFF Primary power supply control transistor: Normally ON

0605 Power ON/OFF Power control Circuit

0606 Power ON/OFF Excess voltage protection circuit: Goes OFF when primary input voltage of 16V or less
0610 Excess current detection Goes ON When detecting excess current and turns OFF DC-DC converter
0611,612 DC output voltage detection Goes ON when detecting DC output voltage from power amplifier