F i g u r e 29. Assembly A7400, parts location..
(5) Move the 411A to connector P7501-
trouble isolation in assembly
C and P5701-D. The normal indi-
A7500 is complete.
c a t i o n should be less than 3 db
57. Isolating Troubles in Assembly A7600
(6) Move the 411A to connector P7501-
Refer to figure 39 for circuit details --
M and P7501-L and adjust the
and figure 31 for test point and parts loca-
666A output frequency to 5.6446
tion.
mc 100 cps as indicated by the
a. Preparation.
AN/USM-26 and for a 0-db indi-
(1) S e t T S - 1 7 7 7 / V R M - l s e l e c t o r
cation on the 411A.
switch S7902 to position 14.
(7) Move the 411A to connector P7501-
(2) Connect Hf Signal Generator 606A
C and P7501-D. The normal indi-
to the test probe, and adjust for an
c a t i o n should be less than 3 db
output frequency of 11.500 mc at
down.
0 volt.
(8) Move the 411A to connector P7501-
(3) Connect Rf Millivoltmeter 411A to
M and P7501-L and adjust the 606A
connector P7601-C.
output frequency to 5.6434 mc 100
(4) C o n n e c t the ME-26B/U to con-
cps as indicated by the AN/USM-
nector P7801-H and adjust it to in-
26 and for 0-db indication on the
d i c a t e + volts dc on the 30-volt
411A.
scale.
(9) Move the 411A to connector P7501-
b. Gain Test.
C and P7501-D. The normal indi-
(1) Adjust the 606A output for a 411A
c a t i o n should be less than 6db
indication of 10 mv.
down.
(2) Adjust potentiometer R7611 for a
(10) If the indication obtained in (3),
m a x i m u m indication on the ME-
(5), (7), or (9) above are not nor-
26B/U.
mal, replace filter FL7501.
(11) If the indications obtained in (3),
(3) A d j u s t transformers T 7 6 0 1 and
T 7 6 0 2 and inductor L7603 for a
(5), (7), or (9) above are normal,
58
