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Muting Level
Note:
No adjustment is necessary. However, if the check-
up is required, take the following steps.
1. Release the MONO/FM
MUTE OFF pushbutton during
this adjustment procedures.
2. Connect
a VTVM
and an Oscilloscope to the Rec. out
jacks on the rear panel.
3. Set the
RF
generator
to 108 MHz, a modulation
of
1 kHz and a deviation of 75 kHz, to provide an input
of 8uV.
4. Turn
VR101
clockwise
and remember
the point (or
position) at which the muting ceases operating.
5. Turn VR101
counterclockwise slightly so that the out-
put level drops by 1 dB.
6. Attenuate the output of the RF generator to 2 dB from
8 uV of step 2 and check that the muting is still oper-
ating.
8-(2)
AM
Section
Tracking and Sensitivity
Low Frequency
1. Press to AM position
2. Connect the RF generator to the antenna terminals on
the
rear
panel,
set
this
to
600kHz
(603 kHz)
with
30 %modulation at 400 Hz.
3. Connect an AC VTVM
and an Oscilloscope to the Rec.
Out jacks on the rear panel.
4. Set
the
frequency
display
of
the
unit
to
600 kHz
(603 kHz).
5. Adjust T201, T202, T203 and the ferrite bar antenna
adjusting the coil to maximize the output signal.
High Frequency
6. Set the
RF
generator
to
1400 kHz
(1404 kHz)
with
30 %modulation at 400 Hz.
7. Set the frequency
display
of the unit
to
1400 kHz
(1404 kHz).
8. Adjust
the
trimmers
TC201,
TC202
in the
tuning
_
gang so that the output signal is maximized.
9. Repeat
these
high
and
low
frequencies
adjustment
procedures
alternately
until
maximum
sensitivity
is
obtained.
9.
Power Amplifier Idling Current Adjustment
Procedure
R738
Right
channel
Adjustment Location of TX X-267 [_]-1 Main Amp. P.C. Board Ass'y
Precaution:
(1) Allow
the set to warm
up at least 5 minutes
before
connecting
aDC VTVM.
(2)
Must keep the heatsinks cooling to prevent overheating
and
consequent
destruction
of the
semiconductor
junction
and
set
the
volume
control
to
minimum
during these adjustment procedures.
(_): for Right channel Adjustment
R-S77
No.2520
Fig. 14
Procedures:
1. Turn
R737
and
(R738)
fully counterclockwise
before
the power switch on.
2. Connect
a DC VTVM
to the Test Point L-CH and L-E
(R-CH and R-E).
3. Adjust R737 (R738) for DC VTVM
reading of 5 mV.
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