Adjustment - Sharp QT-CD161 Service Manual

QT-CD161/141
MECHANISM SECTION
• Driving Force Check
Torque Meter
PLAY: TW-2412 Over 120 g
• Torque Check
Torque Meter
Play: TW-2111 25 to 65 g.cm
Fast Forward: TW-2231 60 to 130 g.cm
Rewind: TW-2231 60 to 130 g.cm
• Head Azimuth
Torque Meter
MTT-114 Output: Speaker Terminal
(CNP201 Load resistance: 8 ohms)
• Tape Speed
Adjusting
Test Specified
Point
Tape
3,000 ± 90 Hz
MTT-111 In motor
TAPE SECTION
Position of each switch or control
Volume control
Function switch
X-BASS
• Bias Oscillation
Adjustment Point Specified Value
82 kHz ± 6 kHz
L301
– 6 kHz
• Playback Amplifier Sensitivity Check
Test Tape Specified Value
1.8 V ± 3 dB
MTT-118
AM TRACKING
fL fH
TC1
L3
TP1
AM BAR
ANTENNA
R7
L2
FM IF
L1
FM RF
T1
1
IC1
Figure 6-2 ADJUSTMENT POINTS

ADJUSTMENT

Specified Value
Specified Value
Specified Value
Instrument
Value Connection
Output: Speaker
Teaminal
(CNP201 Load
resistance: 8 ohms)
Max
Tape/Power Off
On
Instrument
Connection
Pin 2 of CNP201
Instrument Connection
Speaker Terminal
(Load resistance: 8 ohms)
FM ROD ANTENNA
AM BAND
COVERAGE MAIN PWB
TP2
R26
T2
VR1
L4
FM DET.
19 13
21 17
VCO
IC2
1
T3
AM IF
FM BAND
COVERAGE
TUNER SECTION
fL: Low-range frequency
fH: High-renge frequency
• FM RF
Signal generator: 1 kHz, 75 kHz dev., FM modulated
Test Stage Frequency
Band —
Coverage
RF 90.0 MHz
(10~30 dB)
*1. Input: Antenna, Output: TP1
*2. Input: Antenna, Output: Speaker Terminal
• Detection
Signal generator: 10.7 MHz, FM sweep generator
Test Frequency Frequency
Stage
IF 10.7 MHz 98.00 MHz
• AM IF/RF
Signal generator: 400 Hz, 30%, AM modulated
Test Stage Frequency
IF 450 kHz
Band —
Coverage
Tracking 600 kHz
1,400 kHz
*1. Input: Antenna, Output: Pin19 of IC2
*2. Input: Antenna, Output: Speaker Terminal
*3. Input: Input is not connected,
• VCO Frequency
Adjusting Point
76 kHz ± 200 Hz
VR1
Note:
After preparing the test circuit shown in Fig. 6-1, connect the
Pin 13, Pin 21 and ground of the IC2 with the test circuit, and
measure the value. At this time, apply a standard unmodulated
signal input and adjust the VCO.
Pin 13 of IC2 Pin 21 of IC2
FET : 2SK19 or 2SK54
D
G
S
10 kohm
Figure 6-1 VCO FREQUENCY TEST CIRCUIT
– 6 –
Frequency Setting/
Instrument
Display
Adjusting Connection
Parts
87.5 MHz (fL): L2 *1
2.0 ± 0.1 V
90.0 MHz L1 *2
Setting/
Instrument
Display
Adjusting Connection
Parts
T1(Turn Input: Pin 1 of
the core of IC1
T1 fully Output: TP2
counter-
clockwise.
Frequency
Setting/ Instrument
Display Adjusting Connection
Parts
1,720 kHz T3 *1
530 kHz (fL): L4 *3
1.4 ± 0.05 V
600 kHz (fL): L3 *2
1,400 kHz (fH):TC1
Output: TP1
Specified Instrument
Value Connection
Pin 13, pin 21 and
ground of IC2
TO FREQUENCY
COUNTER