Adjustment - Sharp WQ-740W Service Manual

MECHANISM SECTION
• Driving Force Check
Torque Meter
Play: TW-2412
• Torque Check (For WQ-740W)
Torque Meter
Play: TW-2111 30 to 60 g.cm
Fast forward: TW-2231 55 g.cm more
Rewind: TW-2231 55 g.cm more
• Torque Check (For WQ-780W)
Torque Meter
Play: TW-2111 30 to 60 g.cm
Fast forward: TW-2231 80 to 135 g.cm
Rewind: TW-2231 80 to 135 g.cm
• Head Azimuth
Test Tape
MTT-114
* Open the cassette holder, and load the test tape directly into
the mechanism. (Do not load the tape into the cassette
holder.)
• Tape Speed (Normal only)
Test Tape

Adjustment

Point
Tape 1,2:VR501 3,000 ± 60 Hz Headphones
MTT-111
DECK SECTION
• Bias Oscillation
• Beat Cancel Switch: A
Adjustment Point Specified value
100 kHz ± 4 kHz
T301
Beat Cancel
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ADJUSTMENT
Specified Value
Tape 1: Over 60 g
Tape 2: Over 50 g
Specified Value
Tape 1 Tape 2
30 to 60 g.cm
55 g.cm more
55 g.cm more
Specified Value
Tape 1 Tape 2
30 to 60 g.cm
55 to 120 g.cm
55 to 120 g.cm
Instrument Connection
Headphones Socket
(Load resistance: 32 ohms)
Specified Instrument
Value Connection
Socket
(Loadresistance:
32 ohms)
Instrument
Connection
Pin 1 of CNS108
Specified Value
A: 100 ± 4 kHz
B: 94 ± 4 kHz
C: 104 ± 4 kHz
TUNER SECTION
fL: Low-range frequency
fH: High-renge frequency
• FM IF/RF
Specified Value/
Test Stage
Adjusting
Point
IF T201
Detection T202
Band fL: L202
Coverage fH: TC202
Tracking fL(88.0 MHz): L201
fH(108 MHz): TC201 32 ohms)
• AM IF/RF
Specified Value/
Test Stage
Adjusting
Point
IF T203
MW Band fL: L203
Coverage fH: TC203
MW Tracking fL(600 kHz): L206
fH(1,400 kHz):TC207
SW1 Band fL(2.3 MHz): L204
Coverage fH(7.3 MHz): TC204
SW1 fL(2.6 MHz): L207
Tracking fH(6 MHz): TC209
SW2 Band fL(7.3 MHz): L205
Coverage fH(22 MHz): TC205
SW2 fL(8.5 MHz): L208
Tracking fH(19 MHz): TC210
• VCO Frequency
Adjustment
Specified value
Point
76 kHz ± 200 Hz
VR201
Note:
After preparing the test circuit shown in Fig. 5, connect the Pin
13, Pin 21 and ground of the IC202 with the test circuit, and
measure the value.
Pin 13 of IC202 Pin 21 of IC202
G
10 pF
1M ohm
10K ohm
Figure 5 VCO FREQUENCY TEST CIRCUIT
– 5 –
WQ-740W/WQ-780W
Instrument
Connection
Input: FM Antenna
Output:Pin 9 of IC202
Input: Antenna
Output: Headphone Socket
(Load resistance:
Instrument
Connection
Input: Antenna
Output: Pin 9 of IC202
Input: Antenna
Output: Headphone Socket
(Load resistance
32 ohms)
Instrument Connection
Pin 13, Pin 21 and ground
of IC202
D
FET: 2SK212
(or Other 2SK Type FET.)
S
TO FREQUENCY
0.1 µF
COUNTER