RCA SSB-1 Instruction Book page 36

(18) Adjust carrier
(C-240) for half capacitance and turn TRANS­
MITTER GAIN control to zero.
(19) Turn TRANSMITTER switch on
and CARRIER switch to IN.
plate current.
(20) Throw CARRIER switch to OUT
and change tap no. 1 of (L-201) one turn at
a time. At each turn, put CARRIER switch
on and note plate current reading.
this procedure until a peak value of plate
current is obtained.
tap setting for L-201.
TUNING CAP 1 (C-208) for a dip in plate
current. Only a slight
capacitor should be required if the antenna
circuit has been properly resonated.
NOTE: If unable to note
plate current as the antenna coil
changed, increase coupling to
circuit by rotating ANTENNA
CAP 1 (C-201) clockwise one or two turns,
retune PA PLATE TUNING CAP 1 (C-208)
for dip in plate current and repeat proce­
dure as in paragraph 8
III.
(21) Set CARRIER switch to OUT and
raise the TRANSMITTER GAIN control set­
ting. Full load conditions are obtained if
the PEAK MODULATION INDICATOR lights
coincident with 190-200 rna of plate current.
(22) If the PEAK MODULATION INDI­
CATOR lights coincident with PA plate cur­
rent below 190 rna,
clockwise in small increments, dipping the
plate current with C-208 after each change.
Raise the TRANSMITTER GAIN setting after
each change unti l full load conditions exist.
(23) the PEAK
If
DICATOR lights coincident with plate current
in excess of 200 rna turn capacitor C-201
counter clockwise, dipping the plate current
with C-208, until conditions of full load exist.
(24) Align channels 2, 3 and 4 by re­
peating steps (14) through (23) above, using
the proper P. A. tuning and coupling capaci­
tors for each channel.
(25) The TRANSMITTER GAIN control,
with a 1 volt audio
approximate mid-position for. full load con­
ditions on all channels.
level capacitor
Note value of
Repeat
This is the correct
Readjust P. PLATE
A.
variation of the
any rise in PA
tap is
the antenna
COUPLING
and in Section
£ g
turn capacitor C-201
MODULATION IN­
input , should be at its
NOTE: If an audio oscillator is not avail­
able the tone oscillator in the SSB-1 may
be used. Follow channel alignment proce­
dure as described in Section III, paragraph
8.
(26) PA NEUTRALIZ.ATION- The set­
ting of the PA neutralizing capacitor C-215
will very seldom require adjustment.
for re-neutralization will be apparent
cessive plate dissipation in the PA tubes is
noted with full output (plate slightly red) or
an oscillatory
if
at the higher frequencies.
If neutralization adjustment is required,
connect a 0-3 amp (or lower) RF �mmeter
in series with the dummy
transmitter controls
alignment and the
for channel 4, advance the TRANSMITTER
GAIN control for
P A plate current and vary the plate tuning
capacitor C-205 through resonance as in­
dicated by the dip in PA plate current.
note the reading of the RF ammeter.
dip in plate current
maximum current as indicated on the RF
ammeter when the PA is properly neutra­
lized. If this is not the case vary the setting
of neutralizing capacitor
increments until plate current dip and maxi­
mum output current are coincident.
the locking screws on
neutralization.
(27) CARRIER
couple a suitable oscilloscope to the dummy
antenna with CHANNEL switch set on chan­
nel no. 1. Remove the audio oscillator from
terminals 14 and 15
TRANSMITTER GAIN
With no audio input adjust 250 kc balance
(C-243 and R-225)
(C-234 and R-215) for minimum output on
the oscilloscope. This adjustment is critical
and should be done in
interaction between
the 250 kc balance first
balance second.
(28) CARRIER LEVEL ADJUSTMENT­
Reconnect the audio oscillator across ter­
minals 14 and 15 of TB-102.
kc signal at a 1 volt level.
32
Need
if
condition exists, usually
antenna. With
set as for channel
CHANNEL switch set
approximately 130 rna
Also
should coincide with
C-215 in small
Tighten
C-215 and recheck
BALANCE - Closely
of TB-102. Set the
to its mid-position.
and 1150 kc balance
steps there being
the controls. Adjust
and the 1150 kc
Inject a 1000
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