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If
r e s i s t o r R39 o r R93 should e v e r r e q u i r e replacement, the gener-
a t o r should be r e t u r n e d to the factory f o r readjustment o r , i f quali-
fied personnel i s available, the procedure f o r centering the selective
amplifier output level for the t h r e e ranges, described i n paragraph
4-12, may be performed.
4-5
CAPACITOR DRIVE
The s p e c i a l wire cable a r r a n g e m e n t used f o r rotating the two tuning
capacitors i n the Model 206A h a s a life f a r beyond the. life of the
equipment. However
should any drive failure e v e r occur
the i n -
s t r u m e n t should be r e t u r n e d to the factory for r e p a i r .
Under no
c i r c u m s t a n c e s should adjustment of the drive be attempted, since
such a n attempt will destroy the calibration of the instrument.
4-6
ADJUSTMENT O F REGULATED POWER SUPPLY VOLTAGE LEVEL
The level of the regulated output voltage may be m e a s u r e d either a t
the cathode of tube V11 o r V12.
1.
T u r n the POWER switch to ON, and allow a few minutes f o r
warmup.
2.
Connect a voltmeter to pin 8 of V11 o r V12. The voltage between
the cathode and ground should m e a s u r e 240 volts f 5 volts.
3.
Adjust r e s i s t o r R81 (located a s shown i n Fig. 4) a s n e c e s s a r y
to bring the voltage within the proper range.
4-7
ADJUSTMENT O F OSCILLATOR OUTPUT
1.
Connect a high-impedance vacuum tube voltmeter, such a s a
Hewlett-Packard Model 400B, C, o r D to the center t a p of v a r i -
able r e s i s t o r R18 (Fig. 4). With the Model 206A generating
1,000 cycles, the voltage f r o m the center t a p of R18 to ground
should m e a s u r e 21 volts f l volt.
2 .
Adjust variable r e s i s t o r R18 to obtain 21 volts
+
1 volt.
4-8
ADJUSTMENT O F SELECTIVE AMPLIFIER GAIN
With oscillator output voltage a t the proper level ( p a r a g r a p h 4-7),
if the output of the instrument falls below r a t e d level o r the output
waveform shows clipping, the gain of the selective amplifier may
need readjustment. P r o c e e d a s follows:
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