EasyManua.ls Logo

Sharp QT-15XW - QT-15 XW FM IF;RF Alignment; FM IF Circuit Alignment; FM RF Circuit Alignment

Sharp QT-15XW
12 pages
Print Icon
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
FM
IF/RF
ADJUSTMENT
m
Set the mode selector switch
(SWlOl)
to FM position.
-0
Set the signal generator to produce a signal of
400Hz,
30%.
FM modulated.
l
For adjustment in step
1,
see
[Note].
TEST
FRE- DIAL
AD-
STEP BAND
STA-
QUEN-
SET-
JUST-
REMARKS
GE CY
TING
MENT
IF [Connect instruments as shown in Figure 5-l
.)
High
Adjust for
1
FM IF
10.7
MHz
end of
Tl
dial
T2
best “S”
curve.
I
L
I
RF (Connect instruments as shown in Figure
5-2.)
_..
_-~
Low
2
FM
Band
87 .I
MHz
end of L3
cover-
dial
Adjust for
maximum
output.
6
Repeat steps
2,3,4
and 5 until no further improvement
can be made.
When ceramic filters other than the one (red)
having
the
central frequency of 10.7 MHz are used, note that a marker
(10.7
MHz) of FM sweep generator, if used, will be deviated
-
therefore, adjust the generator by putting off the marker.
10
7
MHZ
FM SWEEP GENERATOR
“S
OSCILLOSCOPE CURVE
TP2
TP5
Figure
5-l
FM
IF
FM SIGNAL
GENERATOR
Telescopic
Earphone
ELECTRONIC
VOLTMETER
TP2
Figure
5-2
FM
RF
w
To Tslncopic Rod
Antenna
w
To
Chassis
GND
2:
Output
impedance
of
signal
gsnertior
Figure
5-3
FM
DUMMY
, Color Mark
1. Input
2. GND
3. output
Figure
5-4
NOTES ON SCHEMATIC DIAGRAM
1.
Resistor:
. The voltages in each part are measured with no signal given,
Unless otherwise specified, resistors are shown in ohm,
by using a digital
multimeter
with the unit in play mode.
K
(1000 ohm), and
1/4W
type.
The following must also be observed:
2.
Capacitor:
Radio circuit: Voltages without parentheses are for FM
l
Uniess otherwise specified, capacitors are shown in mode,
and those with parentheses for
microfarads,
P
=
Picofarads
AM mode
l
(CH),
(RH)
:
Temperature compensation
l
Specifications or wiring diagram of this model are subject
to change for improvement without prior notice.
-5-

Related product manuals