Sharp GF-780H

®
CIRCUiT ADJUSTMENT (TUNER SECTION)
AM If/Rf
o
o
Electronic
Voltmeter
Electronic
Voltmeter
BW/LW
Bar Antenna
455 kHz
A
Figure 14-1 AM If
Figure 14-2 AM If CURVE
Figure 14-4 SW RF
Figure 14-3 lW!MW Rf
Dummy
(See Figure 14-5)
Rod Antenna
Sweep Test
Generator
Loop
Signal Test
Generator
Loop
I@ d=JlO
SIGNAL 400 Hz, 30%, AM modulated
GENERATOR
TEST FRIO·
DIAL AD-
STEP STAGE QUENCV POINTER
JUST·
REMARKS
SETTING MENT
MWIF
1
IF
455 kHz High T3
Adjust
for
frequency
best "IF" curve.
LWRF
2
145 kHz
Lowest L10
Band
frequency
f---
coverage
3 295 kHz Highest TC8
frequency
Adjust for
maximal output.
4 170 kHz 170 kHz L7
f--
Tracking
5 220
kHz 220 kHz TC5
6
Repeat steps 2,3,4 and 5 until no further improvement can
be made.
MW RF
7 510 kHz
Lowest L9
Band frequency
f---
coverage
8
1,650 kHz
Highest TC7
frequency
Adjust for
maximal output.
9
600 kHz 600 kHz
L7
f---
Tracking
10
1,400 kH 1,400 kH TC4
11
Repeat steps 7,8,9 and 10 until no further improvement
can
be made.
SW RF
12 5.85
MHz Lowest L8
Band
frequency
I--
coverage
13 18.5 MHz Highest TC6
frequency Adjust
for
maximal output.
14
6.5 MHz 6.5 MHz
L6
f---
Tracking
15
16
MHz 16 MHz TC3
16
Repeat steps 12,13,14 and 15 until no further improvement
can
be made.
Figure 14-5 SW DUMMY
...---.l\Nlr-il!-- To Telescopic Rod Antenna
C
<R =30ohms
Z = 50 ohms C = 12 pF
Z:
Output Impedance of Signal Generator
'----------To Chassis GND
i~' ~ ~ LI TC5@)
L2 TC3@
"', eJ'r'~·
TC2 @
'0
16
~ TC7 ~L6TC6@
8 9T2~ ~ ~ ~c~
IC2 I0l L9 LIO
\8!
VRI
~IC3
~
T3
LW
l7
MW
figure 14-6 ADJUSTMENT POINTS
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