Scott 320R 320RL 330R 330RL Service Manual
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Extracted text from Scott 320R 320RL 330R 330RL Service Manual (Ocr-read)
Page 1
Scott 320R,330Fi/RL
ADJUSTMENT
Equipment Required
Audio signal generator.
Level meter,
Oscilloscope
Digital frequency
counter, 0 r 100 kllz.
FM multiplex signal generator,
Circuit tester, 20 kohle.
FM RF Tracking
FM
[3 ZZTmy Tape/Rec @
Out
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05-4-12: 2: a . 0
FM Signal FM Ant Level Meter Oscilloscope
Generate! 300 Ohm
1) Apply 90 MHz, 1 kllz and 100% modulated, 65 dHf signal
with 75 kHz deviation to the FM antenna terminal.
2) Time the unit to 90 Mllz.
3) Observe the oscilloscope connected to the Tape/Rec output
terminal for symmetrical sine wave, If failed. adjust 1'3.
4) Adjust T1, and 'l2 for maximum level meter rcading
FM IF Amplifier
Shel/dad 72
O Coax Cable
Sweep Generator ground ., - W V. 7'. 7 _
l) Mute the FM local oscillator by shorting CV3,
2) Connect oscilloscope to pin #13 of 1C2.
3) Apply 10.7 MHz signal from the sweep generator to 1'2
in the manner as shown as above.
4) Adjust T4 for correct figure as shown. It may be necessary
to increase or decrease the sweep generator output for
adjustment convenience
O o 8:9-3- 3 turn coil
9 B
__o 0--
C
Distortion Analyzer
(connected in parallel with the oscilloscope).
5) Rcadjust the signal generator for 106 Mill, and retune unit.
6) Repeat step 3). if failed, adjust the trimming capacitor,
C'l'c.
7) Adjust the trimming capacitors, (Il'a and (I'l'b.
13446, etc. 0;
r' ------1/
I
I
l
>\ r l
470k 7 :
, nmn
To chassrs <- wr - 1 o
J Oscilloscope
Correct Incorrect, Incorrect,
as too low as too narrow
Page 2
Tuning Meter
1) Remove signal generator output from the unit.
2) Adjust T5 for exact center reading on the FM Center Tun-
IF Distortion
1) Apply 98 MHz, 1 kHz and 100% modulated, 65 dB! signal
to the unit.
FM Signal Strength Meter [330R/RL only]
1) Apply 98 MHz, 90 dBf signal to the unit.
2) Tune the unit for 98 MHz.
Mute Circuit
1) Apply 98 MHz. 20 dBf signal to the unit,
2) Tune the unit (with the Mute switch in the Off position).
Pilot Signal (76 kHz)
1) Apply 98 MHz, 65 dBf signal to the unit with no modu-
lation,
2) Adjust RV4 for 76 kHz reading on the frequency counter
Stereo Separation
1) Apply 98 MHz. 65 dBf left channel signal to the unit modu-
lated with 1 kHz. 9% pilot signal of 6.75 kHz deviation.
2) Connect a digital voltmeter to the right channel Tape/Rec
output terminal.
3) Adjust RV3 for minimum leakage (minimum level) on the
voltmeter.
AM IF Amplifier
1) Apply 455 kHz sweep generator output to the unit AM
antenna terminal.
2) Connect scope to the pin number 12 of ICS.
3) Adjust T8 to obtain maximum and symmetrical display as
shown,
AM (MW) Tracking
1) Apply 600 kHz. 30% modulated with 1 kHz to the AM bar
antenna. See test setup figure (Distance between the AM
ha: antenna and emitting loop antenna should be 2 feet).
2) Adjust signal generator output so that a sine wave appears
on the scope.
3) Adjust T9 for maximum audio output on the digital volt-
ing meter.
2) Adjust T6 for minimum distortion on the distortion ana-
lyzer connected to the Tape/Rec output terminal.
3) Adjust RVl (or 90% reading on the signal strength meter.
3) Set the Mute switch to the On position
4) Adjust RV2 so that the signal is muted.
connected between T? and chassis ground. A deviation of
1200 Hz is acceptable.
4) Apply 98 MHz. 65 dBf right channel signal to the unit
modulated same as step 1).
5) Move digital voltmeter to the left channel Tape/Rec output
terminal.
6) Adjust RV3 for minimum level.
meter connected parallel with the scope. When turning
core. always adjust signal generator output to maintain
proper level. Do not change voltmeter range. Moreover.
always keep the generator output as low as possible to
avoid AGC action and to keep the measurements accurate.
4) Adjust the AM loopstick antenna core for maximum output