Specifications

(a) Signal voltage chart.
Circuit junction
I
Signal voltage (rms)
P7601-C
C7601 and T7601
T7601 and C7603
Q7601 base
T7602 and C7609
R7605 and R7606
T7602 and C7610
Q7602 base
Q7602 collector
R7606 and C7611
4.9 mv
3.0 mv
5.7 mv
5.6 mv
5.6 mv
17.0 mv
33.0 mv
34.0 mv
2.5 v
27.5 mv
(b) Dc voltage chart.
Circuit junction
+dc voltage to
ground (volts)
P7601-H
C7604 and R7603
Q7601 base
Q7601 emitter
R7605 and R7606
Q7602 base
Q7602 emitter
R7608 and C7611
CR7602 and R7611
P7601-K
15.3
16. 3
5.35
5.55
8.0
7.6
7.66
8.0
3.1 (rectified
signal)
2.0 (rectified
signal)
(3) Remove the test signal and set the
TS-1777/VRM-l ON-OFF switch
to OFF.
(4) Replace the faulty part.
(5) Repeat b and c above.
58. Isolating Troubles in Assembly A7700
Refer to figure 39 for circuit details and
figure 32 for aid in locating the parts.
a. Preparation for 5.65-Mc Amplifier
Tests.
(1)
(2)
(3)
(4)
Set TS-1777/VRM-1 selector
switch S7902 to position 15.
Adjust Hf Signal Generator 606A
for a frequency of 5.650 mc with an
output of O volt and connect it to the
test probe.
Connect Rf Millivoltmeter 411A to
connector P7701-M.
Connect the ME-26B/U to con-
nector P7801-H and adjust to in-
dicate + volts dc on the 30-volt
scale.
b. Gain Test for 5.65-Mc Amplifier.
(1) Adjust the 606A output for a 411A
indication of 150 mv.
60
(2)
(3)
(4)
(5)
Adjust potentiometer R7708 for a
maximum indication on the ME-
26B/U.
Adjust inductor L7704 for a max
imum indication on the ME-26B/U.
A normal indication should be +3.2
volts dc minimum.
Increase the 606A output to 300 mv
as indicated on the 411A. A normal
indication should be +4.5 volts dc
minimum.
If the indication obtained in (3) and
(4) above are low or absent, pro-
ceed to d below.
c. Bandwidth Test for 5.65-Mc Ampli-
fier.
(1)
(2)
(3)
(4)
(5)
(6)
Adjust the 606A for a 411A indi-
cation of 150 mv.
Adjust potentiometer R7708 for an
ME-26B/U indication of +3 volts
dc.
Adjust the 606A frequency to 4.600
mc and adjust the output level to
maintain a 411A indication of 150
mv. A normal indication should be
+1.5 volts dc ±0.3.
Adjust the 606A frequency to 6.8.
—
mc and adjust the output level to
maintain a 411A indication of 150
mv. A normal indication on the
ME-26 B/U should be +1.5 volts
dc ±0.3.
If indications obtained in (3) and
(4) above are normal, proceed to
e below.
If indications obtained in (3) and
(4) above are low, proceed to d
“below.
d. Trouble Isolation in 5.65-Mc Ampli-
fier.
(1)
(2)
Adjust the 606A for a frequency of
5.650 mc at a level of 18 mv as in-
dicated on the 411A.
Measure the signal and dc volt-
ages listed in the chart below to
isolate the faulty part. Measure the
ac voltages with an ME-30B/U; _
measure the dc voltages with an
ME-26B/U.