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c
Set the TRA N SMITTER GAIN for a full
output on
f
sponse.
f
TRANSMITTER GAIN control must be most
advanced for full output.) Keeping the oscil
f
loscope coupled to the antenna, set the level
on the oscilloscope for 20 divisions at full out
f
put. Set the TRANSMITTER GAIN at mini
mum.
f
adjust capacitor C240 for 10 divisions on os
«
cilloscope. Raise the TRANSMITTER GAIN
c
control until the PEAK MODULATION INDI
CATOR lights. Pattern on oscilloscope should
f
appear as a two-tone signal with a sharp
cross-over point as illustrated in the figure
below.
(
t
c
c
c
«
c
t
t
5. R E P L A C E M E N T A N D T U N I NG
(
O F
FILTER TYPES- Three slightly differ
a_.
(
ent variations of mechanical filters, FL201
and FL202, have been supplied. All of these
pass an upper sideband approximately 3 kc
t
wide while rejecting the 250 kc carrier.
t
c
t
EQUIPMENT
•
SERIAL
c
NUMBERS
c
t
5501
•
to
55250
•
I
5601
to
56200
I
56201
•
and
above
I
the channel with the lowest re
(This is the channel
Throw the CARRIER switch to IN and
M E C H A N I C A L
TABLE 4. COMPONENTS USED WITH FILTERS
MECHANICAL
FILTER
FL201
FL202
Type
F250Z-4
(modified)
Type
F250Z-4
Type
MFU-250-1
cause of the variations, however, certain dif
ferent accessory components are used with
each of the three type filters. These compo
where the
nents are li sted in Table 4 and shown in the
schematics and P arts List.
Q..
anical filters FL201 and FL202 are designed
for continuous duty over long periods of time
without maintenance, it may become neces
sary to replace one because of failure due to
overloading, burn-out or physical damag e .
Direct replacement of one filter by another
of the same type will require no special pro
cedure except that,
Numbers 5601 and above, the new filter will
require tuning in accordance with paragraph
c. below. In case the filter to be installed is
of a different type than the one in the equip
ment, proceed as follows:
modified or not, may be used. No filter tun
ing is provided. Type MFU -250-1 filters can
not be installed in these equipments.
F I L T E R S .
with T ype F-250Z-4 filters at the factory. Di
rect replacement by a modified F-250Z-4 (as
supplied for spares on Serial Nos. 5501 to
55250) is satisfactory and the new filter should
Be-
then be tuned in accordance with paragraphg_.
CAPACITORS
C312
C313
C238
C314
C294
C315
Not
Used
91uuf
7-45uuf 68uuf
20 to
125uuf
360uuf
REPLACEMENT- Although the mech
irr equiprnents Serial
(1) FOR EQUIPMENTS SERIAL NOS.
5501 TO 55250.
Type F-250Z-4 filters whether
(2) FOR EQUIPMENTS SERIAL NOS.
5601 TO 56200.
These equipments are supplied
RESISTORS
C242
R285
C293
R255
R286
C242-82uuf
Not
Not
C293-91uuf
Used
Used
Not
Not
62uuf
Used
Used
33K,
47K,
360uuf
1/2W
1/2W A-1214593
BRA C KET
A201
(4 req'd)
Not
Used
Radiomarine
A-1214592
Radiomarine
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