Scott 320R Service Manual

ADJUSTMENT
FM RF Tracking
FM Signal
Generator
Scott
320R,330R/RL
FM
Equipment Required
Aud io signal generator.
Level meter.
Oscilloscope.
Digital frequency counter, 0 - 100 kllz.
FM multiplex signal generator.
Circuit tester , 20 ko hm/ V.
Ant Out
D ~ m m y Tape / Rec
[:::zJ
- o + - ~- -...u
FM Ant
300Ohm
Tf--:t:Q_-..S?::J--t-.--t:Q.... _
_J
Level Meter
Oscilloscope
OJ
Distortion Analyzer
I) Apply
90
MHz,
I
kllz and
100%
m odulated, 65 dHf signal
with 7 5 kHz deviation to the FM antenna terminal.
(con~ected in parallel with the oscilloscope).
2)
Tune the unit to 90 MIiz.
3) Observe the oscilloscope connected to the Ta pe/ Rec output
terminal for symmetrical sine v:ave. If failed, adjust T3 .
4) Adjust Tl , and T2 for maximum level meter reading
FM IF Amplifier
1) Mute the FM local oscilla tor by shorting CV3.
2) Connect oscilloscope to pin #13 of IC2.
3) Apply 10.7 MHz signal from the sweep generator to T2
in the m anner 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.
5)
Readjust the signal generator for 106 MIiz, and retune unit.
6) Repeat step 3), if failed, adjust the trimming capacitor,
ere.
7) Adjust the trimming capacitors, era and CTb .
1S446, etc.
r· · - -
Correct
0.00/µF
I
Oscilloscope
Incorrect,
as too low
Incorrect,
as too narrow