Component Description; Operation - Kenwood KDC-5021 Service Manual

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ELECTRIC UNIT (X25-922x-xx)
REF.
No.
IC1 SYSTEM u-COM
IC2 E-VOL/NC/MPX
IC3 MUTE
IC4 POWER IC
IC5 SWITCHING OP AMP
IC7 RDS DEMODULATOR
IC8 RESET IC
IC9 EEPROM
Q1 FM+B SW
Q2 FM+B SW
Q3 AM+B SW
Q4 AM+B SW
Q6 IFC BUFFER
Q201 PRE MUTE SW (FRONT Lch)
Q202 PRE MUTE SW (FRONT Rch)
Q203 PRE MUTE SW (REAR Lch)
Q204 PRE MUTE SW (REAR Rch)
Q205 PRE MUTE SW (NON-FADER Lch)
Q206 PRE MUTE SW (REAR Rch)
Q401 E-VOL MUTE SW
TE
L 13942296513
Q402 NOISE BUFFER
Q403,404 AUDIO MUTE DRIVER
BU & MOMENTARY POWER
Q501
DOWN DETECTOR
Q502 ACC DETECTOR
Q503,504 P-ANT SW
Q505 P-CON SW
Q506 P-CON PROTECTOR
Q507 P-CON PROTECTOR
Q508 P-CON SW
Q510 SMALL LAMP DETECTOR
Q701,702 BU 5V AVR
Q703 SW 5V
AUDIO 8V & SERVO +B AVR
Q704,705
ON/OFF SW
Q706,707 AUDIO 8V AVR
Q708 SERVO +B AVR
Q901-903 ILLUMINATION AVR
Q905 PANEL 5V SW
Q906 GUIDE ILLUMI SW
Q907 EJECT KEY & DSI ILLUMI SW
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COMPONENT DESCRIPTION

FUNCTION
System u-com.
E-volume, Noise Chancellor, Multiplexer.
4 inputs, 3 NOR gates.
Power IC.
Switches operation amplifier.
Demodulates RDS.
"L" when detection voltage goes below 3.0V.
EEPROM.
Q1 turns on when Q2 base level goes "H".
Turns on when FM signal exists.
Q3 turns on when Q4 base level goes "H".
Turns on when AM signal exists.
Shapes wave form.
Mutes when the base level goes "H".
Mutes when the base level goes "H".
Mutes when the base level goes "H".
Mutes when the base level goes "H".
Pre mute SW.
Pre mute SW.
Mutes E-vol when the base level goes "H".
Buffers noise.
Turns on when the base level goes "L".
Turns on when the base level goes "H" during the back-up effects.
Turns on when the base level goes "H" during ACC effects.
Q503 turns on when Q504 base level goes "H".
Q505 turns on when Q508 base level goes "H".
Protects Q505 by Q506 turning on when P-CON output effect stops.
Prevents Q507 turning on during being stand-by after turning power on.
Q505 turns on when Q508 base level goes "H".
Turns on when the base level goes "H" during illumination lights.
Turns on when the back-up effects.
Turns on when the base level goes "L".
Q704 turns on when Q705 base level goes "H".
Output voltage is 8.3V.
Output voltage is 7.4V.
AVR output turns on when Q901 base level goes "H".
Turns on when the base level goes "L".
Turns on when the base level goes "L".
Turns on when the base level goes "L".
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OPERATION

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