79. Alining Second Doubler
d. If the OUTPUT meter needle drifts away from
a. Place the FREQ RANGEMC selector in the 100-
the center scale reading, note the deflection.
200 me position.
to cool.
c. Form coil L17 to produce a maximum reading
f. Adjust R129 and R130 to new positions for
on the output meter.
center scale indication with 100,000 microvolts output.
Note the direction of adjustment.
g. Repeat the procedures given in c, d, and e
e. Vary capacitors C37 and C39 equally for a
above. If deflection increases, readjust R129 and R130
maximum output reading.
in the opposite direction from that noted in f above.
f. Repeat procedure outlined in b through e above
h. Repeat procedure outlined in g above until the
to obtain the highest output readings.
deflection is negligible.
80. Alining Third Doubler
83. Adjusting Audio-frequency Oscillator
a. Set the FREQ. RANGE-MC selector to the
200400 me position.
indicator between pin 1 of V1 and ground. Use
Frequency Meter 67/U or its equivalent.
c. Form coil L20 to produce a maximum reading
b. Rotate the DEVIATION control to obtain a full-
on the output meter.
scale reading on KILOCYCLES DEVIATION meter M1.
c. Set the MODULATION selector to 1000-.
e. Vary the front panel control 200-400 MC
d. Adjust capacitor C8 for a 1,000-cps indication at
TRIMMER for maximum output reading.
the af indicator.
f. Repeat procedure outlined in b through e above
e. Set the MODULATION selector to 1600-.
to obtain a maximum output reading.
f. Adjust capacitor C7 for a 1,600-cps reading at
the af indicator.
81. Calibrating Output Signal Level
g. Set the MODULATION selector to 20KC.
a. Barretter bridge model 202B and fixed
attenuator S/N 2Z9944-16, or their equivalents, are
h. Adjust capacitor C6 for a 20,000-cps reading at
required for output calibration.
the af indicator.
b. Connect the R. F. OUTPUT to the fixed
Note. If any of the audio frequencies cannot be
attenuator, using output cable W2, terminated in
obtained, adjust capacitor C9. This will shift the overall
Adaptor Connector UG-564/U. Connect the pad directly
af range up or down in accordance with the adjustment.
to the Barretter bridge.
After adjusting C9, capacitors C6, C7, and C8 must be
readjusted (o through h above).
c. Adjust the OUTPUT control of the signal
generator to produce a reading of 50 millivolts (50,000
i. Disconnect the af indicator.
microvolts) on the Barretter bridge.
j. Connect a precision audio distortion indicator
between pin 1 of V1 and ground. Use Spectrum
100,000 microvolts, since a 2: 1 voltage lose ratio is
Analyzer TS-723/U or its equivalent.
Introduced by the fixed attenuator.
k. Adjust potentiometer R27 for a distortion
reading of less than .2 per cent at 1,000, 1,600, and
20,000 cycles per second.
center scale (SET TO LINE).
l. Disconnect the distortion meter.
82. Adjusting Output Temperature Compensation
84. Adjusting Deviation Compensation and Deviation
a. Connect the equipment as directed in
Calibration
paragraphs 81a, b, and c.
a. Set R65 to approximately midrange.
b. Set the OUTPUT control to obtain a
100,000microvolt reading at center scale (par. 81).
100 me band.
Maintain the 50,000-microvolt reading at the Barretter
c. Set the MODULATION selector to 20KC and the
bridge throughout the following adjustments.
DEV MULT switch to X10, rotate the DEVIATION control
fully counterclockwise.
block.
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