Sharp QT-CD121H (serv.man2) Service Manual ▷ View online
– 5 –
QT-CD121H/112H
QT-CD112H
1. Cassette Compartment
2. CD Compartment
3. Fine Tuning Control
4. Band Selector Switch
5. Tuning Control
6. (TAPE) Record Button:
7. (TAPE) Play Button:
8. (TAPE) Rewind Button:
9. (TAPE) Fast Forward Button:
2. CD Compartment
3. Fine Tuning Control
4. Band Selector Switch
5. Tuning Control
6. (TAPE) Record Button:
7. (TAPE) Play Button:
8. (TAPE) Rewind Button:
9. (TAPE) Fast Forward Button:
10. (TAPE) Stop/Eject Button:
11. (TAPE) Pause Button:
12. CD Eject Button:
11. (TAPE) Pause Button:
12. CD Eject Button:
/
13. (CD) Play Indicator:
14. (CD) Track Number Indicator
15. (CD) Repeat Indicator:
16. Volume Control
17. Stand-by, On/Function Switch
18. Extra Bass Button: X-BASS
19. (CD) Track Down/Review Button:
20. (CD) Track Up/Cue Button:
21. (CD) Stop Button:
22. (CD) Play/Repeat Button:
14. (CD) Track Number Indicator
15. (CD) Repeat Indicator:
16. Volume Control
17. Stand-by, On/Function Switch
18. Extra Bass Button: X-BASS
19. (CD) Track Down/Review Button:
20. (CD) Track Up/Cue Button:
21. (CD) Stop Button:
22. (CD) Play/Repeat Button:
23. FM/SW Telescopic Rod Aerial
24. Headphones Socket
25. Battery Compartment
26. AC Power Input Socket
24. Headphones Socket
25. Battery Compartment
26. AC Power Input Socket
1
2
3
6
7 8
9
10
11 12
4
5
13 14
15
16 17 18 19 20 21 22
23
25
26
24
Remote Sensor
(8" - 20')
15
15
Notes concerning use:
Replace the batteries if control distance de-
creases or operation becomes erratic.
Periodically clean the transmitter LED on the
remote control and the sensor on the main unit
with a soft cloth.
Exposing the sensor on the main unit to strong
light may interfere with operation. Change the
lighting or the direction of the unit.
Keep the remote control away from moisture,
excessive heat, shock, and vibrations.
creases or operation becomes erratic.
Periodically clean the transmitter LED on the
remote control and the sensor on the main unit
with a soft cloth.
Exposing the sensor on the main unit to strong
light may interfere with operation. Change the
lighting or the direction of the unit.
Keep the remote control away from moisture,
excessive heat, shock, and vibrations.
0.2 m - 6 m
REMOTE CONTROL (121H ONLY)
– 6 –
QT-CD121H/112H
1
Rear Cabinet
1. Screw ................. (A1) x10
6-1
2. Socket .................. (A2) x1
6-2
2
Top Cabinet
1. Knob ..................... (B1) x1
6-2
(with CD Mechanism/ 2. Screw ................... (B2) x3
Tape Mechanism/
Tape Mechanism/
3. Socket .................. (B3) x1
Main PWB)
3
Main PWB/
1. Screw ................... (C1) x8
6-3
Switch PWB/
2. Socket .................. (C2) x4
6-3,6-4
Headphones PWB
4
Tape Mechanism
1. Screw ................... (D1) x4
6-4
5
CD Mechanism
1. Screw ................... (E1) x3
6-4
6
Terminal PWB
1. Screw ................... (F1) x7
6-5
2. Hook ..................... (F2) x1
DISASSEMBLY
Caution on Disassembly
Follow the below-mentioned notes when disassembling the
unit and reassembling it, to keep it safe and ensure excellent
performance:
1. Take cassette tape and compact disc out of the unit.
2. Be sure to remove the power supply plug from the wall
Follow the below-mentioned notes when disassembling the
unit and reassembling it, to keep it safe and ensure excellent
performance:
1. Take cassette tape and compact disc out of the unit.
2. Be sure to remove the power supply plug from the wall
outlet before starting to disassemble the unit.
3. Take off nylon bands or wire holders where they need be
removed when disassembling the unit. After servicing the
unit, be sure to rearrange the leads where they were
before disassembling.
unit, be sure to rearrange the leads where they were
before disassembling.
4. Take suffcient care on static electricity of integrated
circuits and other circuits when servicing.
STEP
REMOVAL
PROCEDURE
FIGURE
Figure 6-4
Figure 6-3
Figure 6-5
Figure 6-1
Figure 6-2
(Illustration: QT-CD121H)
(A1)x3
ø3x12mm
ø3x12mm
(A1)x1
ø3x12mm
ø3x12mm
(A1)x6
ø3x20mm
ø3x20mm
Rear Cabinet
Front Cabinet
(B2)x3
ø3x12mm
ø3x12mm
(A2)x1
(B3)x1
Front Cabinet
Top Cabinet
(B1)x1
Main PWB
Headphones
PWB
PWB
(C1)x7
ø3x10mm
ø3x10mm
(C2)x1
Switch PWB
(C1)x1
ø3x10mm
ø3x10mm
Main PWB
Top Cabinet
Headphones
PWB
PWB
Top Cabinet
Tape
Mechanism
CD Mechanism
(E1)x3
ø2.5x10mm
ø2.5x10mm
(D1)x4
ø3x10mm
ø3x10mm
(C2)x2
(C2)x1
(F1)x2
ø3x12mm
ø3x12mm
(F1)x2
ø3x14mm
ø3x14mm
Terminal PWB
Driver
Push
(F2)x1
(F1)x1
ø3x10mm
ø3x10mm
Spacer PWB
– 7 –
QT-CD121H/112H
CD MECHANISM SECTION
Perform steps 1, 2, 3 and 5 of the disassembly method to
remove the CD mechanism.
remove the CD mechanism.
How to remove the pickup (See Fig. 7.)
1. Remove the screws (A1) x 2 pcs., to remove the shaft (A2)
x1 pc.
2. Remove the stop washer (A3) x1 pc., to remove the gear
(A4) x 1 pc.
3. Remove the pickup.
Figure 7
REMOVING AND REINSTALLING THE MAIN PARTS
(A1) x2
2.6 x6mm
2.6 x6mm
Stop
Washer
(A3) x1
Washer
(A3) x1
CD
Mechanism
Mechanism
Gear
(A4) x1
(A4) x1
Shaft
(A2) x1
(A2) x1
Pickup
– 8 –
QT-CD121H/112H
Instrument
Connection
MECHANISM SECTION
• Driving Force Check
PLAY: TW-2412
Over 120 g
Torque Meter
Specified Value
• Torque Check
Torque Meter
Specified Value
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
• Tape Speed
MTT-111 In motor
3,000
±
90 Hz
Output: Speaker
Teaminal
(CNP201 Load
resistance: 8 ohms)
Teaminal
(CNP201 Load
resistance: 8 ohms)
Instrument
Connection
Specified
Value
Test
Tape
TAPE SECTION
Position of each switch or control
Volume control
Max
Function switch
Tape/Power Off
X-BASS
On
• Bias Oscillation
• Playback Amplifier Sensitivity Check
Instrument Connection
Test Tape
MTT-118
1.8 V
±
3 dB
Speaker Terminal
(Load resistance: 8 ohms)
(Load resistance: 8 ohms)
Specified Value
ADJUSTMENT
TUNER SECTION
fL: Low-range frequency
fH: High-range frequency
fH: High-range frequency
• FM IF/RF
IF
T1
Detection
T2
Band Coverage
fL: L2
fH: TC2
fH: TC2
Tracking
88.0 MHz: L1
108.0 MHz: TC1
108.0 MHz: TC1
Test Stage
Specified
Value/Adjusting
Point
Instrument
Connection
Input: Pin 1 of IC1
Output: Pin 17 of IC2
Output: Pin 17 of IC2
Iuput: Antenna
Output: Speaker
Terminal (CNP201
Load resistance: 8
ohms)
Output: Speaker
Terminal (CNP201
Load resistance: 8
ohms)
• VCO Frequency
Specified
Value
Instrument
Connection
VR1
76 kHz
±
200 Hz
Pin 13, pin 21 and
ground of IC2
ground of IC2
Adjusting Point
Note:
After preparing the test circuit shown in Fig. 8, 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.
After preparing the test circuit shown in Fig. 8, 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.
Figure 8 VCO FREQUENCY TEST CIRCUIT
• Head Azimuth
Torque Meter
Specified Value
MTT-114
Output: Speaker Terminal
(CNP201 Load resistance: 8 ohms)
(CNP201 Load resistance: 8 ohms)
Adjusting
Point
Adjustment Point
Specified Value
L301
82 kHz
±
6 kHz
Pin 2 of CNP201
IF
T3
Input: Antenna
Output: Pin 19 of IC2
Output: Pin 19 of IC2
MW Band
fL: L4
Input: Antenna
Coverage
fH: TC4
Output: Speaker
Terminal (CNP201
Load resistance: 8
ohms)
Terminal (CNP201
Load resistance: 8
ohms)
Test Stage
Specified
Value/Adjusting
Point
Instrument
Connection
• MW/SW IF/RF
MW Tracking
600 kHz: L3
1,400 kHz: TC3
1,400 kHz: TC3
SW Band
fL: L6
Coverage
fH: TC5
SW Tracking
6.5 MHz: L5
16 MHz: TC6
16 MHz: TC6
QT-CD121H
Instrument
Connection
Adjustment Point
Specified Value
L301
82 kHz
±
6 kHz
Pin 2 of CNP201
– 6 kHz
QT-CD112H
Pin 13 of IC2
Pin 21 of IC2
D
G
S
10 kohm
TO FREQUENCY
COUNTER
COUNTER
FET : 2SK19 or 2SK54
IF
T3
Input: Antenna
Output: Pin 19 of IC2
Output: Pin 19 of IC2
Band Coverage
fL: L4
Input: Antenna
fH: TC4
Output: Speaker
Terminal (CNP201
Load resistance: 8
ohms)
Terminal (CNP201
Load resistance: 8
ohms)
Test Stage
Specified
Value/Adjusting
Point
Instrument
Connection
• AM IF/RF
Tracking
600 kHz: L3
1,400 kHz: TC3
1,400 kHz: TC3
QT-CD121H
QT-CD112H
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