Adjustment - Sharp CD-C472 Service Manual

CD-C472/C3400/C3400C/C3800/C3800C
MECHANISM SECTION
• Driving Force Check
Torque Meter
Play: TW-2412
• Torque Check
Torque Meter
Play: TW-2111 30 to 60 g. cm
Fast forward: TW-2231 —
Rewind: TW-2231 —
• Tape Speed
Adjusting
Test Tape
Normal MTT-111 Volume in
speed motor.
(MM1)
TUNER SECTION
fL: Low-range frequency
fH: High-renge frequency
• AM IF/RF
Signal generator: 400 Hz, 30%, AM modulated
Test Stage Frequency
IF 450 kHz
Band —
Coverage
Tracking 990 kHz
*1. Input: Antenna, Output: TP302
*2. Input: Antenna, Output: TP301
TAPE MECHANISM
Volume in motor
Specified Value
Tape 1: Over 80 g
Tape 2: Over 80 g
Specified Value
Tape 1
Tape 2
30 to 60 g.cm
60 to 120 g.cm
60 to 120 g.cm
Specified Instrument
Point Value Connection
3,000 ± Speaker
30 Hz terminal
(Load
resistance:
8 ohms)
Frequency Setting/ Instrument
Display Adjusting
Connection
Parts
1,720 kHz T351 *1
530 kHz (fL): T302 *2
1.1 ± 0.1 V
990 kHz (fL): T302 *1
MM 1
Motor
FM BAND
COVERAGE fL
TP302
VR351
VCO
Figure 12-1 ADJUSTMENT POINTS

ADJUSTMENT

• FM RF
Signal generator: 1 kHz, 75 kHz dev., FM modulated
Test Stage
Band
Coverage
RF
*1. Input: Antenna, Output: TP301
*2. Input: Antenna, Output: Speaker terminal
• Detection
Signal generator: 10.7 MHz, FM sweep generator
Test
Stage
Detection 10.7 MHz
IF
• VCO Frequency
Frequency
98.00 MHz
(60 dB)
* Adjust for 76 kHz ± 200 Hz.
Notes:
After preparing the test circuit shown in Fig 12-2, connect the
Pin 13 , Pin 21 and ground of the IC303 with test circuit, and
measure the Value.
At this time, apply a standard unmodulated signal input and
adjust the VCO.
Pin 13 of IC303
G
MAIN PWB
1
IC301
L303
L302
FM RF
T301
FM IF
R316
T351
AM BAND
AM IF
COVERAGE fL
1
IC303
13 21
T302
T352
R340
AM TRACKING
FM DET
fL
– 12 –
Frequency Frequency
Display
— 87.50 MHz L303(fL):
3.4 V ± 50 mV
98.00 MHz 98.00 MHz L302
(10-30 dB)
Frequency
Frequency Adjusting
Display
98.00 MHz T352
10.7 MHz 98.00 MHz T301(Turn
the core of
transformer Output: TP302
T352 fully
counter-
clookwise.)
Frequency Adjusting
Display
98.00 MHz VR351*
Pin 21 of IC303
FET : 2SK19 or 2SK54
D
S
10 kΩ
Figure 12-2
TP301
Serring/ Instrument
Adjusting Connection
Point
*1
*2
Instrument
Parts Connection
Input: Pin 1 of
IC303
Output: TP302
Input: Pin 1 of
IC301
Instrument
Parts Connection
Pin 13, Pin 21
and ground
of IC303
TO FREQUENCY
COUNTER