TM 11-6625-596-45
Action and indication
Possible cause
Correction
MICROPHONES OTHER TYPES
Open circuit------------------------------------ Check continuity between 1A3J2-F,
button 1A4S6J depressed; no
1A4S6J-1, 1A4S6J-2, and 1A3J8-C.
deflection of meter.
MICROPHONES-CARBON button
Open circuit------------------------------------ Check continuity between 1A3J2-F,
1A4S6K depressed; no deflection
1A4S6K-1, 1A4S6K-2, and1A3J8-C.
of meter.
Connect 220-ohm resistor from MICROPHONES CARBON terminal 1A4El to LO terminal 1A4E2. Depress READ MIC CURRENT
button 1A4S5F and slowly turn MICROPHONE CURRENT control 1A4R1. Meter 1A4M1 should read from 0 to 60.
No reading on 1A4M1--------------------
Open circuit------------------------------------ Check continuity between:
a. 1A3J5-H, 1A3LI-1, 1A3Ll-2, and
1A4R2-2.
b. 1A4R2-1, 1A4S.6K-4, and 1A4A1-1.
c. 1A4A1-2 and 1A4E1.
d. 1A4E2 and 1A3J8-L.
e. 1A3J8-R and 1A4S5F-5.
Depress DIAL BREAK button
No 24 volts de at 1A3J9-D----------------- Check voltage; check continuity between
1A4S6L.
1A3J9-D, 1A4S6L-7, and 1A3J5-H.
No meter deflection when DIAL
Open circuit to 1A4M1
Check continuity between:
BREAK control 1A4E18 is roated
a 1A3J9-J and 1A4S6L-5.
b. 1A4S6L-2 and 1A4R18-2.
c. 1A4R18-1 and 1A3J1-D.
d. 1A4R18-3 and 1A3J10-H.
Replace 1A3A9.
Depress DIAL SPEED button
No simulated dial pulse at 1A3J9-C------- Check continuity between;
1A4S6L; no meter deflection when
a. 1A3J9-B and 1A3R15-2.
DIAL SPEED control11A4R17 is
b. 1A3R15-1 and ground.
rotated.
No simulated dial pulse at 1A3J10-J --- Check continuity between 1A3J9-C
and 1A3J10-J.
No simulated dial pulse at 1A3J10-L----- Replace 1A3A10.
No simulated dial pulse at 1A3J10-K----- Check continuity between 1A3J10-K,
1A4S5A-8, 1A4S5A-7, and 1A3J10-L.
No monostable multivibrator pulse
Replace 1A3A10. Check continuity below.
at 1A3J10-P.
No monostable multivibrator pulse
Check continuity between:
at 1A3R17-1.
a. 1A3R17-1 and 1A3J10-P.
b 1A3R17-2 and 1A3J10-B.
c. 1A3R17-3 and 1A3J10-D.
Open circuit to11A4M1----------------------- Check continuity between:
a. 1A3J10-F, 1A4S6M-9, and
1A4S6M-8.
b. 1A4S6M-5 and ground.
High reading of meter; needle cannot
be brought below midscale by turn-
must have an on time of .050 second
or
ing DIAL SPEED control 1A4R17.
1A3A10 defective.
more and a period of exactly 0.10
has a period less than .10 second with
3-4.
Voltage Measurements
Control
Position
a. General.
Voltage measurements at
NOISE GEN ADJ button 1A4S6A------------
Depressed
recepta-cles 1A3J1 through J10 (FIG. 3-3 in to which
TEST CONDITION switch 1A4S9-----------
COUPLER
DRIVER
listed in the charts in b through k below. Voltage
VALUE controls C and D 1A4AT3 and
0
1A4AT4.
1A3T1 (FIG. 3-3) are listed in the chart in 1 below.
LEVEL controls A and B 1A4AT1
0
Measure the voltages with the test equipment specified,
and 1A4AT2.
and with test microphone 1A2A4A4 directly over test
MICROPHONE LOAD switch11A4S1-------
OFF
loudspeaker 1A2A2.
RECEIVER LOAD switch 1A4S2------------
OFF
(1) Unless otherwise specified, controls are set
BATTERY switch 1A4S4-----------------------
CB
as follows:
(2) Adjust the CALIBRATE controls listed in
the Control column of the chart below for a
3-21