Kenwood KCAR-42-FM Service manual

FM MODULATOR

KCA-R42FM

(K, M type) SERVICE MANUAL

Antenna cord assy (E30-4310-08)

B51-7708-00(S) 1744

CASE (A01-2695-08)

Holder assy (B07-2138-08)

DC cord assy (E30-4733-08)

Magic tape assy (W01-0763-08)

Display unit assy (T95-0244-08)

Battery ∗ Not supplied as service parts

Remote controller assy (A70-0896-05)

KCA-R42FM

ACC

BATT

GND

DETECTION

ACC

(+5V)

AVR

LC72329

u-COM

IC2

IC1

CN101

DRIVER

RESET

CN102

MODE 1,2

Q308

CD-CH

13P

IC101

ISOLATION

AMP. L.P.F.

2nd.

IC102

EMPHASIS

IC301

MODULATOR

FM-St.

Q306,

STAGE

Q304,305

LEVEL CONTROL

AUDIO MUTE

Q309

ALC

DETECTION

IC302

AMP

Q101,201

DRIVER

ALC

CN103

IC4

AVR(+5.6V)

RIPPLE

FILTER

307

RL1

CN105

RADIO

CN104

ANT IN

Q1,6

Q4,5

Q310

MODE 1,2

VDD

HOLD

CH-CONTROL

P ON

MIX

MPX

+V(AUDIO)

+V(RF STAGE)

PLL

SIGNAL

(L/R)

12-17 26 61

29,30,60

74,77

PILOT

KCA-R42FM

BLOCK DIAGRAM

●DISPLAY UNIT

KCA-R42FM

COMPONENT DESCRIPTION

Ref No.

IC1 LC75852W LCD driver with key-matrix IC2 PNA4602M Remote control light senser Q1 DTC144EK Q2 DTB123YK Q3 DTA144EK key-matrix permition sw ready on key-matrix Q4 DTC144EK Q5 DTA114EK

Component Name Appication / Function Operation / Condition / Compatibility

LED on / off sw

IC2 on / off sw

●RF MODULATOR UNIT

Ref No.

IC1 UPC7805AHF BU 5V AVR IC2 LC72329-9274 System MI-COM. IC4 NJM78L05UA 5V AVR IC101 NJM2060M Isolation amp. IC102 NJM4565MD Low pass filter IC301 BA1405F FM ST modulator IC302 NJM4565MD 1/2 Vcc driver, ALC detection amp Q1 DTC124EK ACC detection Q2 2SA1782(T,U) Q3 DTC124EK Q4 DTC143TK Reset sw Q5 DTC143TK CH-Reset sw Q6 DTA124EK Hold detection sw Q8 DTC143TK Relay driver Q9 2SC4640(T,U) Ripple filter Q101 2SK2158 Q201 2SK2158 Q303 2SA1162(GR) Pilot mix amp Q304 Q305 Level 2/4:L, Level 1/3:H Q306 2SK508L RF oscillator buffer Q307 2SC2714(Y) RF amp. Q308 2SK2158 Mode (1/2) sw Mode1:H, Mode2:L Q309 2SK2158 Audio mute Power on:L, Power off:H Q310 2SK2158 Mode (1/2) sw Mode1:L, Mode2:H

Component Name Appication / Function Operation / Condition / Compatibility

Power sw

ALC control sw

2SK2158 Level control sw

Level 1/2:L, Level 3/4:H

KCA-R42FM

●

RF MODULATOR UNIT

1. DC balance adjustment (VR301)

While observing the waveform with a oscilloscope at pin 13 of IC301, adjust VR301 to minimize the waveform level.

ADJUSTMENT

2. PLL control voltage adjustment (VC301)

First set the transmission frequency to *87.9 MHz with the commander, then adjust VC301 so that the DC Voltage at the + pole of C317, measured using a multimeter or digital tester, is + 3V (± 0.1 V).

3. Modulation level adjustment (VR303)

The method using a standard receiver or tuner. Adjust VR303 so that the output level from the standard receiver or tuner is as specified.

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