Sharp WOQ-272H(R) - Tuner Section Circuit Adjustment

"Ory 4 als)
=
AM (F/RF
ease
400 Hz, 30%, AM modulated
ease
TEST FRE- AD-
STEP | STAGE | QUENCY |POINTER | JUST-
SETTING | MENT
MW IF (Set the band selector switch to MW position.)
High T3
frequency
LW RF (Set the band selector switch to LW position.)
Lowest L10
Band frequency
coverage
Highest
A en
Repeat steps 2 and 3 until no further improvement can be
made.
re 170 Kitz | 170 KHz
raf 270 kHz | 270 KH
7 Repeat steps 5 and 6 until no further improvement can
be made.
Adjust for
best “IF” curve.
Adjust for
maximal
output.
Adjust for
maximal
output.
Tracking
MW RF (Set the band selector switch to MW position.)
Lowest
frequency
Adjust for
maximal
output.
Band
coverage Highest
4 dieduency
ie steps 8 and 9 until no further improvement
can be made.
ake | on ite or |
Haid sponte re.
Repeat steps 11 and 12 until no further improvement
can be made.
Adjust for
maximal
output.
o Tracking
SW RF (Set the band selector switch to SW position.)
Lowest L8
frequency
Band
ee Highest | TC6
frequency
he steps 14 and 15 until no further improvement can be
made.
pesmi [esmez |i |
[temnz | rome [rcs |
Repeat steps 17 and 18 until no further improvement
can be made.
Adjust for
maximal
output.
Adjust for
maximal
output.
Tracking
CIRCUIT ADJUSTMENT (TUNER SECTION)
Oscilloscope
Test MW/LW
Loop Bar Antenna
Sweep
Generator
Figure 12—1 AM IF
455 kHz or 468 kHz
Figure 12—2 AM IF CURVE
Electronic
MW/LW Voltmeter
Bar Antenna
Test
Loop
Signal
Generator
IC3
@ Pin
GND
Figure 12-3 LW/MW RF
Electronic
Dummy
Voltmeter
(See Figure 12—5)
Signal
Rod Antenna
Generator
Figure 12—4 SW RF
§}—eTo Telescopic Rod Antenna
Cc
R = 30 ohms
C=12pF
Z: Output impedance of signal generator
To Chassis GND
Z = 50 ohms
Figure 12—5 SW DUMMY
L7(LW)
Tuner P.W.B.
Figure 12-6 ADJUSTMENT POINTS
40