Kenwood KAC 7252 Service Manual

Page 2

KAC-7202/7252

BLOCK DIAGRAM

ISO AMP LPF/OFF/HPF POWER AMP
ICIZJS lCl(X08) 579345 024 242 02017255
L BASS '
LINE IN © BOOST MUTE +
L 40710on Sp OUT L
LINE OUT ©7 MO/ST fo-
R SENS
LINE our @-
a
BASS
LINE IN © BOOST «I MUTE ~o+
407100H2 Sp OUT a
151 REMOTE -|
L CONTROL 7 CONTROL BOON
SP IN I GAIN
l:407100Hz
GAIN:0718dB
R -o BATT
SP IN 0- :15V AVR o.o. CON.
To GND

COMPONENTS DESCRIPTION

. PREAMPLIFIER UNIT (X08-4190-1 X) Ref. No. Application / Function

Ref. No. Application / Function 0101 Remote controller relerence voltage
|C1 HPF 0201 ~204 Power amplifier initial step diflerential driving
|C2 Phase reversal amplifier (Lcn only) 0209,210 Current limiter
|C3 LPF 0205~208 Power amplifier second step differential driving
|C4~6 Bass-boost circuit 0211,213 Temperature detection for idling
|C7 Bass-boost mixing amplifier 0220222427229 Power amplifier final

0241 ,242 Power amplifier mute
0251 ~258 Power amplifier driver
0 AUDIO UNlT (X09-5830-1x) 0280,282 Power amplifier ATT (-3dB)

Ref. No. Application / Function 0601 ,615~618 Power-ON shock preventer circuit
|C1,12,16 Input isolation amplifier 0602 P-Con OFF detection
ICS DC/DC converter 0603 Mute drive
ICG Temperature detection comparator 0604,605 P-Con control circuit
|C7,8 For adjusting bass-boost f 0606 Excess voltage detection
ICQ For adjusting bass-boost gain 0601606619620 Temperature detection control circuit
|C13 Bass-boost phase shifter 0609 Fan power supply
|C15 Bass-boost mixing amplifier 0610 Excess current detection
01,2 i15V AVR 0611,612 DC detection
03~8 DC/DC converter FET 0613,614 DC detection for latch
09~12 DC/DC converter FET driver 0621 ,622 For LED control
013,14 For controlling DC/DC converter FET driver 0623 Temperature detection control circuit

ADJ USTMENT
No. ITEM ALIGNMENT POINT METHOD ALIGN FOR NOTE
IDLE VR1 (Lch) Connect a DC voltmeter After Power on
1 between check land 2.5mV
CURRENT VR2 (Rch) 5 minutes
(Refer to PC BOARD)