Western Electric 407A-4, Инструкция по эксплуатации

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Units C, D and E should be completely adjusted
for 50-kw operation before adjustments for 5-kw
emergency operation are attempted, and accord­
ingly D6G ( control transfer switch ) sh ould be in
the 50-kw position, D2H (50-kw Rect. Fil. Switch)
closed, and D5G ( 5-kw Rect. Fil. Switch ) open.
Adjustment of Input Circuit
The only adjustment necessary in the grid circuit of
this stage consists in tuning circuit L31C-C32C to series
resonance at the carrier frequency. The short-circuiting
strap used in tuning the D-99110 Oscillator Amplifier Unit
having been removed from this circuit, a cathode-ray tube is
connected by means of jack JlC
"RF
By-Pass Tuning, 11 with
switch D31C closed, and excitation is applied from the oscil­
lator amplifier unit. C32C
"RF
By-Pass Tuning" is then ad­
justed to minimum deflection on the cathode-ray tube.
If a
minimum is not obtained within the range of C32C, new taps
are chosen on L31C until the require d minimum is obtained.
Switch D31C is then opened.
After this adjustment has been made, the tuning of the
oscillator-amplifier should be found to be the same as when
L31C-C32C was short-circuited.
Neutralization
The modulating amplifier is neutralized by applying
excitation with switch D30C in the test position and with a
cathode-ray tube connected at jack J2C "Neutralizing. " C5C
"Neutralizing" is adjusted for minimum deflection on the
cathode-ray tube. This minimum should be obtained at be­
tween half and full scale setting of C5C.
A tap on L5C
should be chosen that will give this result.
In adjusting L5C 9 if there are more than five or six un­
used turns they should be shorted to avoid the building up of
excessive voltages.
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