RCA SSB-1, Инструкция

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Replacement of a Type F-250Z-ll
filter by a Type MFU-250-1 fili:er requires
that additional components be changed as list­
ed in Table 4 and shown in Figure 21C. Pro­
ceed as follows:
(a) Remove filter tuning capac­
itors C312 and C313 and brackets A201, if
FL201 is being changed. Remove C314 and
C315 with brackets A201 if FL202 is being
replaced.
or FL202.
(b) Remove old filter unit FL201
in place.
(c) Mount new MFU -250-1 filter
(d) Replace filter tuning capac­
itors C312 to C315 with capacitors of proper
value (20-125 uuf) for MFU-250-1 filter. See
Table 4. New bracket A201 are required for
these capacitors.
(e) Replace capacitors C238 and
C242 or C293 and C294 with 360 uuf capacitors
as required for the new filter.
(f) Rewire filter circuit per the
schematic Figure 29B, inserting resistors
R285 and R286 ahead of FL201 and/ or R255
in the output circuit of FL202 as required.
(g) Tune filter in accordance
with paragraph
£."
below.
(3) FOR EQUIPMENTS SERIAL
NOS. 56201 AND ABOVE:
Replacement of the Type MFU-
250-1 filter installed at the factory by a Type
F-250Z-4 filter requires replacement of tun­
ing capacitors and removal of resistors as
follows:
(a) Remove filter tuning capaci­
tors C238 and C242 or C293 and C294 and
also brackets A201.
(b) Remove resistors R255 and/
or R285 and R286 and discard them.
(c) Remove the filter FL201 or
FL202.
(d) Mount new Type F-250Z-4
filter"
(e) Replace filter tuning capaci­
tors C312 and C313 and/or C314 and C315
with 7-45 uuf capacitors and new bracket A201.
(f) Replace capacitors C238 and
C242 or C293 and C294 with new ones of value
as specified in Table 4 for the F-250Z-4 filter.
(g) Tune filters in accordance
with paragraph
£..
belpw.
£..
TUNING- The m,ethod of tuning the me­
chanical filters is the same for the Type
F-250Z-4 and Type MFU -250-1 except that
they should be peaked at slightly different
audio {sideband) frequencies. Location of fil­
ter tuning capacitors is shown in Figure 31C.
36
TO TUNE
TRANSMITTER
SIDEBAND FILTER FL201.
(1) Set filter tuning capacitors C312
and C 313 approximately in mid-position.
(2) Connect the output from an Audio
Oscillator to terminal 4 on one of the Remote
Desk Set terminations on TB103. Connect
the corresponding terminal 5 to terminal 3
(ground).
(3) Set controls on the SSB-1 as
follows:
TELEGRAPH-PHONE to PHONE
LOCAL-REMOTE to REMOTE­
position corresponding to connections made
in paragraph (2) above.
TRANSMITTER GAIN at 0.
(4) Insert leads from a 0-250 rna de
milliameter into the METER LINK jacks ob­
serving proper polarity as marked on the
chassis.
(5) Energize the transmitter on a
channel for which a crystal is availabl!=!.
(6) Adjust Audio Oscillator output
to 1800 cps if a Type F-250Z-4 filter is used
or to 1950 cps if Type MFU-250-1 filter is
used.
NOTE: If an Audio Oscillator is not avail­
able, temporary field adjustments
made using the tone oscillator (1000 in
the SSB-1. In this case, omit steps (2), {3)
and (6). Start with the TRANSMITTER GAIN
set at 0. (Permanent adjustments should be
made at the earliest opportunity using the pro­
per frequency).
(7) Increase TRANSMITTER GAIN
until a reading is obtained on the milliameter
and then tune capacitor C313 for maximum
reading on the meter. Use an insulated screw­
driver for all adjustments.
NOTE: Never allow meter reading to ex­
ceed 90 rna. Throughout this procedure use
TRANSMITTER GAIN control to keep meter
reading at or below 60 rna for best operation.
(8) Tune capacitor C312 for maxi­
mum reading on the milliameter using GAIN
control to reduce output
if
necessary.
(9) After tuning is complete set
TRANSMITTER GAIN for 60 rna on the meter
and check tuning points by slightly varying
capacitor C313 and C312 settings, readjust­
ing for maximum output.
{10) Remove meter connections, Os­
cillator connections and ground from termi­
nal 5 on TB103.
TO TUNE RECEIVER
SIDEBAND FILTER FL202.
In order to tune the receiver filter
properly, an R.F. signal adjusted to the cen­
ter frequency of the sideband range of the fil-
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