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GENERAL RADIO COMPANY
Section
4
OPERATING
PROCEDUR1E
4.1 INITIAL ADJUSTMENT.
After the proper connections have been made to the oscillator and
the output rectifier (refer to paragraphs 1.3 and 3.1), apply power, allow
at least a 2-minute warm up, and check operation as follows:
a. Standardize the output voltmeter.
(1) With the selector switch in the ZERO position, turn the ZERO
thumb-set control to zero the meter.
(2) Turn the selector switch to CHECK and observe the meter in-
dication.
(3) Turn the selector switch to CAL and turn the CAL thumb con-
trol to produce the same indication as noted in (2).
b. Turn the selector switch to OPERATE.
c. Select CW or 1-KC
ru
MOD.
d. Set the OUTPUT VOLTAGE control so that the desired operating
voltage is indicated on the meter. If it is impossible to reach this level
by advancing the OUTPUT VOLTAGE control, the oscillator cannot sup-
ply this output. As the normal oscillator output coupling is reduced, the
drop-out point of the regulator will occur abruptly, with no noticeable
change in level down to this point, if the system is operating properly.
If, with normal plate supply, the output from the oscillator is much
greater than desired, the control system may become unstable and break
into oscillation. This condition can easily be observed by the action of
the output meter as the oscillator output coupling is varied.
As the
coupling (control or loop on the oscillator itself) is increased from the
minimum setting, the indicated voltage should rise to the desired output
level, then remain constant over a part of the range of the oscillator out-
put coupling.
Then, if the coupling can be advanced far enough, the
meter will suddenly jump up or down, indicating the unstable oscillating
condition. All General Radio Unit Oscillators are equipped with an ad-
justable output coupling system, so that the above tests can be made.
Once the adjustments have been made, it should be possible to turn the
oscillator dial through the entire frequency range with no noticeable fluc-
tuation in output voltage.
10
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