TM 11-5826-225-35
amplifier Q4 through the 50-ohm
(c) Repeat paragraph d(l) (b) through
probe (fig. 28).
(e) above.
(d) Typical mixer gain values at vari-
(9)
Set control unit function switch to
ous radio frequencies are listed in
ANT and BFOOFF switch to BFO.
the following chart. If mixer gain
Tune for zero beat on 200 kc and then
differs appreciably from the chart,
set BFOOFF switch to OFF.
check the alignment of mixer stage
(11)
Adjust signal generator output signal
and if necessary, use further isolat-
to produce an indication of 5 volts d c
ing techniques to determine the de-
on vtvm. Record this value of signal.
fective component (para 2-8). After
(11)
C o n n e c t signal generator output
m a k i n g these tests, remove agc
through 50-ohm probe to test point
ground and adjust R90 (para 317 ).
TP-4.
(12)
Adjust signal generator output to pro-
duce an indication of 5 volts dc on
vtvm. Divide this signal generator
output level by the signal obtained in
step (10). A typical gain at 200 kc is
32. Repeat (2) through (12) above
for each frequency listed in the follow-
ing chart, If gain differs from that
listed in that chart, check the align-
ment (para 3-14) and, if necessary,
use further isolating techniques to de-
termine the trouble (para 2-8).
(1) Ground IF amplifier agc test point
TP-3.
(2) Set control unit function switch to
LOOP, range switch to 190- to 400-
kc range, BFO-OFF switch to BFO,
and GAIN control fully clockwise.
Tune to 200 kc.
(3) Connect signal generator to input of
test set. Tune to 200 kc and adjust
output to 100 microvolt.
(4) Tune control unit for zero heat and
f. Gain of Sense Antenna Input Circiut.
then set BFO-OFF switch to OFF,
(1) Repeat e (1) through (7), Then set
(5) Set vtvm for measuring O to 5 volts
control unit function switch to ANT.
dc and connect vtvm to the cathode of
(2) Tune signal generator for maximum
audio detector CRl (fig. 2-14 or 2-14.1).
indication of vtvm, Note the output
(6) Set test set LOOP SIMULATOR dial
si.gnal required to obtain 5 volts dc on
90 degrees from that indicated on
vtvm.
BEARING INDICATOR or for maxi-
mum indication on vtvm. Set GONI
(3) Divide the signal generator output
DRIVE switch to OFF.
signal determined in paragraph e (10)
by the value obtained in (2) above, A
('i) Adjust variable resistor R90 (fig.
typical gain figure at 200 kc is 0.05.
28) for an indication of 5 volts dc on
vtvm,
(4) Repeat (1) through (3) above for the
remaining frequencies listed in the
set and apply signal to the base of RF
following chart. If gain differs appre-
2-27
Change 1
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