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4. Adjustment of neutralization
(1)
(2)
(3)
Purpose:
To
stabilize
operation
by neutralizing
the final
stage.
Measuring instruments:
1)
RF dummy or power meter
2)
RF vacuum tube vo!tmeter
Adjusting procedures:
1)
Connect
the dummy
or the power
meter
to
the ANT terminal.
2)
Obtain the maximum
output at a frequency
of 21.3MHz (CW).
3}
Set the STAND-BY switch to REC and cut off
screen. voltage by the SG switch mounted on
the rear panel of the set.
4)
Connect the RF vacuum tube voltmeter to the
ANT
terminal and set the STAND-BY
switch
to
SEND
and
then
adjust
a
neutralizing
variaole
capacitor
(TC1)
positioned
at the
final shield box so as to minimize the pointer
deflection of the RF voltmeter.
5)
Return
the STAND-BY
switch
to REC
and
disconnect the RF vacuum tube voltmeter and
restore the SG switch.
6)
Set the switch to SEND again the ascertain
that the power is available as before.
7)
Return the switch to REC.
[Note]
© Be careful
not to touch by the hand since the
plate line is always provided with high voltage
(800V).
®@ Continuous
transmission
for more
than
10
seconds by CW is not permitted.
@ Tubes at the final stage must be brought into
an inoperative condition with a ratio of 3 to 1
against all the transmission time.
@ When
the RF vacuum
tube voltmeter
is not
used,
any
type
of receiver
of being able
to
receive
a 21MHz
band may be used.
5.
BM and carrier position (Refer to Fig. 12, 13)
(1)
(2)
(3)
Purpose:
To
adjust the carrier
position
by balancing
the
balanced mixer.
Measuring instruments:
1)
AF generator
2)
AF vacuum tube voltmeter
3)
RF dummy or power meter
4)
RF vacuum tube voitmeter
Adjusting procedures:
1)
Connect a dummy
toad of 75 ohms and the
RF
vacuum
tube.
voltmeter
to
the
ANT
terminal.
2)
Set the MODE switch to CW and the frequen-
cy to 14.2MHz and adjust each knob so that a
maximum power can be obtained.
3)
Next, set the MODE switch to LSB and adjust
the balancing VR (VR2) and trimmer (TC1)
Carrier input
(RX)
MIC
input
4)
5)
VR3
TC2
Balanced Det
TC1
Balanced Mod
(TX)
T1
;
VR1
Carrier
O4 Level Adj
RF output
Fig. 12 X52-0010-00
in the
unit
X52-0010-00
so that
the
RF
vacuum
tube voltmeter will give a minimum
indication.
Apply
7mV,
1500Hz
AF
signal to the MIC
terminal while setting the range of RF vacuum
tube voltmeter to the maximum
voltage posi-
tion
and
obtain
an output
of 50 watts
by
adjusting the MIC GAIN VR (VR6).
At this stage, shift the frequency of AF signal
to 400Hz
and then to 2600Hz
and
perform
fine adjustment of the trimmer TC3 mounted
on the carrier unit X50-0009-00 to regulate
the difference of their outputs within 5 watts.
OUT
6)
7)
8)
Fig. 13 X50-0009-00
Set the MODE
switch to USB
and shift AF
signal to 400Hz and 2600Hz and peform fine
adjustment of the trimmer (TC2) mounted on
the carrier unit X50-0009-00 to rquslate the
difference of their outputs within 5 yatts.
Disconnect
the AF
generator from the MIC
terminal
and rotate the MIC GAINVR
fully
counterclockwise.
Set again the MODE switch to LSB ined adjust
the
balancing
VR2
and
trimmer {(TC1)
in
the unit X50-0010-00 so that the FF vacuum
tube voltmeter will give a minimum in dication
(similar operation to Item 3).
29
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