Technics QUARTZ ST-S4 - Indicator Adjustment

Step
No.
AM SIGNAL GENERATIOR DISPLAY
FREQUENCY
CONNECTION FREQUENCY] BY PRESET
522kHz
(30% Mod.
with 400Hz)
PARTS
PREPARATIONS ADJUSTED
AM-RF ADJUSTMENT
Connect DC VTVM to
522k
Hz
terminal.
L202 (OSC Coil)
Connect AM-SG to
AM antenna termina!
through 200pF
capacitor, Common to
chassis. (Weak input)
612kHz
(30% Mod.
with 400Hz)
Connect AC VT VM or
scope to “OUTPUT”
terminals of the set.
612k Hz L201 (ANT Coil)
ADJUSTING
PROCEDURE
Adjust L202 to
1.0V +0.05V.
. Adjust for maximum output.
2, Adjust ferrite core of L201
by screw driver,
1503k Hz
(30% Mod.
with 400Hz)
FM ADJUSTMENT |
* Equipment used
1. FM signal generator (FM-SG)
Connect AC VTVM or
scope to “OUTPUT”
terminals of the set.
1503k Hz
. Distortion analyser dummy antenna,
. AC and DC electronic voltmeters (VTVM)
. Frequency counter (19kHz and 108MHz measurable)
. FM 300Q dummy antenna (Fig. 9)
“IO O1B GON
72aB.)
¢ Preparation of FM signal generator (FM-SG)
1. Connect stereo modulator to FM-SG.
. Stereo modulator (or separation meter) 2. Apply SG output to antenna terminal of the set through 3009 FM
. Oscilloscope 3. The standard input of the set is GOdB (1mV), 400Hz 100%
modulation (Because of using dummy antenna, SG output must be
12dB plus (1HF). That is, when input is 60dB, SG output is to be
. Adjust for maximum output
CT201 (ANT Trimmer) | 2: Repeat steps (3) and (4) until
the frequency correctly
matches the dial display.
Setting a s was
1,
Set
FM
mode
switch
to
‘‘auto”’
position.
3.
Set
input
selector
to
'‘FM
position,
—
2.
FM
IF
-band
switch
to
‘’normal”
position.
4,
Other
setting
are
the
same
as
in
AM
adjustment.
FM SIGNAL GENERATOR DISPLAY
FREQUENCY INDICATOR ADJUSTMENT REMARKS
CONNECTION FREQUENCY]! BY PRESET POINTS
FM-IF ADJUSTMENT
Connect DC VTVM
Frequency of ', Adjust T1017 core so that
. betwee and J Sle
No-Signal non-inter- LP ort HERG T101 (Discri. IFT) voltage measured in signal
ference coil (Refer to Fig. 11) mode is OV in 300mV range.
_ FM RF ADJUSTMENT
Sj Connect DC VTVM to Adjust L5 (OSC Coil) to
No-Signa! 87 .50MHz taceninal L5 (OSC Coil) BEGIN.
; 1. Add weak input so that
ena
Connect
scope
to
LI
(ANT
Coil)
noise
is
included
in
the
th 200be) | 20:00MHz “OUTPUT” terminals L2 (RF DET Coil, Ist) output wave form.
Connect FM-S§G to with A OHz) of the set. L4 (RF THe Coil, 2nd) 2. Make the adjustment so
FM antenna terminal weak input T1 (FM IFT) that the output wave
through
300]
FM
form
is
vertically
sym-
metrical. Refer to Fig. 12.
BU anne: 106.00MHz Connect scope to 3, Repeat the steps (7) ae
with 400Hz) of the set correctly matches the dial
display.
FM MONO DISTORTION ADJUSTMENT
Connect FM-SG to
FM antenna terminal
through 3000 FM
dummy antenna.
100.00MHz
(100% Mod.
with 400Hz)
Connect distortion
analyser to “OUTPUT”
terminals of the set.
T102
100.00MHz
(Discri.
1FT)
FM dB INDICATOR ADJUSTMENT
Connect FM-SG to
FM antenna terminal
through 3002. FM
100 .OOMHz
(100% Mod.
with 400Hz)
100 .0OMHz V R501
dummy antenna.
aah
. Set the FM mode switch to
“auto” and then check step
(5) in no signal mode.
2. If itisdeflected, readjust
of T101.
. Adjust T102 core so that
distortion of rightand
left channels are
minimized,
GO
. Apply 100.00MHz, 400Hz
100% modulated 62dB
signal to antenna terminal
2. Push the FM signal level
indicator button switch,
and adjust VR501 so that
56dB displayed.
3. Decrease the input down to
30dB and then slowly in-
crease up to 62d B.
4. Make sure that the display
is then 56dB.
If 56dB is not displayed,
re-adjust It.
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