Adjustment; Mechanism Section; Tuner Section - Sharp CD-C422 Service Manual

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
Point
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 Frequency
Display
IF 450 kHz 1,720 kHz
Band — 530 kHz
Coverage
Tracking 990 kHz 990 kHz
*1. Input: Antenna, Output: TP302
*2. Input: Antenna, Output: TP301
TAPE MECHANISM
Volume in motor
FM BAND
COVERAGE fL

ADJUSTMENT

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
Value Connection
3,000 ± Speaker
30 Hz terminal
(Load
resistance:
8 ohms)
Setting/ Instrument
Adjusting Connection
Parts
T381 *1
(fL): T333 *2
1.1 ± 0.1 V
(fL): T331 *1
MM 1
Motor
FM IF
IC302
FM DET
TP303
VR381
VCO
Figure 11-1 ADJUSTMENT POINTS
CD-C422/C422C/C2800/C2800C
• FM RF
Signal generator: 1 kHz, 75 kHz dev., FM modulated
Frequency Frequency
Test Stage
Band —
Coverage
RF 98.00 MHz 98.00 MHz L312
(10-30 dB)
*1. Input: Antenna, Output: TP301
*2. Input: Antenna, Output: Speaker terminal
• Detection
Signal generator: 10.7 MHz, FM sweep generator
Test Frequency
Stage
Detection 10.7 MHz
IF 10.7 MHz
• VCO Frequency
Frequency
Frequency
Display
98.00 MHz 98.00 MHz
(60 dB)
* Adjust for 76 kHz ± 200 Hz.
Notes:
After preparing the test circuit shown in Fig 11-2, 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
IC301
1
L301
1
T302
T301
20 L312
T382
T331
CF301
1
IC303
13 17 21
T333
AM BAND
AM IF
TP302
COVERAGE fL
– 11 –
Serring/
Display Adjusting
Point
87.50 MHz T301(fL):
1.3 V ± 50 mV
Frequency
Adjusting Instrument
Display
Parts Connection
98.00 MHz T382 Input: Pin 1 of
IC303
Output: TP302
98.00 MHz T302(Turn Input: Pin 1 of
the core of IC301
transformer Output: TP302
T381 fully
counter-
clookwise.)
Adjusting Instrument
Parts Connection
VR381* Pin 13, Pin 21
and ground
of IC303
Pin 21 of IC303
FET : 2SK19 or 2SK54
D
TO FREQUENCY
S
COUNTER
10 kΩ
Figure 11-2
MAIN PWB
FM RF
TP301
FM
1
2
AM LOOP ANTENNA
3
AM TRACKING
fL
Instrument
Connection
*1
*2