Western Electric 407A-4, Инструкция по эксплуатации

Страница: 52 / 136

the "Test Meter" switch on the "Vl Plate X20" pos ition.
With the
"RF
Output" control s et at ab out 80, adjus t the
"Plate Circuit Tuning Vl" control unti l the "Test Meter" in­
dicates a minimum, or until the "Test Meter" indicates a
maximum when turned to the posit i on "V2 Grid X5 . 11
Second Radi o-Frequency .Amplifier Tuning
With the "Output Coupling V211 c ontrol set at zero and
the "Test Meter" switch on the 11V2 Plate XlOO" pos ition ad­
just the "Plate Circu it Tuning V2 11 control until the "Test
Meter" indicates a minimum. With the "Output Coupling V2 11
control at approximately 10, adjust the "Output Cil"cuit
Tuning V211 control until the "Test Meter11 indi cates a maxi­
mum. This completes the prel iminary adj ustments of the sec­
ond amplifier plate and output circuits . Place the 11Plate
Rectifier11 switch in the "OFF" pos ition and s et the "RF Out­
put" control on z ero before proceeding with the neutraliza­
tion of the third amplifi er .
Third Radio-Frequency .Amplifier Neutral iz ati on
Connect the radio-frequency rectifiers in the closed
circuit by placing link Dl7A in position 1-3. Check that
D6A and D7A are open. Adjust the tap on LlOA which is as ­
sociated with Dl7A for a number of turns above ground equal
to about 15 per cent of the total active turns . Set the
"Test Meter" control on "VlO Plate X20. " Place the "Output
Coupling 3rd Amp . 11 control at zero and close the "Plate
Rectifier" switch. Set the "Output Coupling V211 control at
approximately 30 and then slowly vary the "Plate C ircuit
Tuning 3rd .Amp . " control in conjunction with the
"RF
Output11
contro l until the "Test Meter11 indicates a maximum. Con­
tinue by increas ing the
"RF
Output" control to a maximum,
meanwhile adjusting the "Neutralizing 3rd Amp. " control to
keep the "Test Meter" reading below 5 milliamperes . Check
45