WQ-740W/WQ-780W
– 5 –
ADJUSTMENT
Figure 5 VCO FREQUENCY TEST CIRCUIT
TUNER SECTION
fL: Low-range frequency
fH: High-renge frequency
Specified value Instrument Connection
VR201 76 kHz ± 200 Hz Pin 13, Pin 21 and ground
of IC202
Specified Value
MECHANISM SECTION
• Driving Force Check
Specified Value
• Torque Check (For WQ-740W)
Play: TW-2111 30 to 60 g.cm 30 to 60 g.cm
Fast forward: TW-2231 55 g.cm more 55 g.cm more
Rewind: TW-2231 55 g.cm more 55 g.cm more
• Head Azimuth
MTT-114 Headphones Socket
(Load resistance: 32 ohms)
Instrument Connection
• Tape Speed (Normal only)
Instrument
Connection
MTT-111 Tape 1,2:VR501 3,000 ± 60 Hz Headphones
Socket
(Loadresistance:
32 ohms)
* Open the cassette holder, and load the test tape directly into
the mechanism. (Do not load the tape into the cassette
holder.)
Specified Value
Beat Cancel A: 100 ± 4 kHz
B: 94 ± 4 kHz
C: 104 ± 4 kHz
DECK SECTION
• Bias Oscillation
Torque Meter
Torque Meter
Test Tape
Test Tape
• Beat Cancel Switch: A
T301 100 kHz ± 4 kHz Pin 1 of CNS108
Adjustment Point Specified value Instrument
Connection
Adjustment
Point
• VCO Frequency
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.
• FM IF/RF
Specified Value/
Adjusting
Point
Test Stage
IF T201 Input: FM Antenna
Detection T202 Output:Pin 9 of IC202
Band fL: L202 Input: Antenna
Coverage fH: TC202 Output: Headphone Socket
Tracking fL(88.0 MHz): L201 (Load resistance:
fH(108 MHz): TC201 32 ohms)
Instrument
Connection
• AM IF/RF
Test Stage
Specified Value/
Adjusting
Point
Instrument
Connection
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
Input: Antenna
Output: Pin 9 of IC202
Input: Antenna
Output: Headphone Socket
(Load resistance
32 ohms)
10 pF
1M ohm
10K ohm
TO FREQUENCY
COUNTER
Pin 13 of IC202
Pin 21 of IC202
FET: 2SK212
(or Other 2SK Type FET.)
G
D
S
0.1 µF
Play: TW-2412 Tape 1: Over 60 g
Tape 2: Over 50 g
Tape 1 Tape 2
Adjustment
Point
Specified
Value
Specified Value
• Torque Check (For WQ-780W)
Play: TW-2111 30 to 60 g.cm 30 to 60 g.cm
Fast forward: TW-2231 80 to 135 g.cm 55 to 120 g.cm
Rewind: TW-2231 80 to 135 g.cm 55 to 120 g.cm
Torque Meter
Tape 1 Tape 2
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