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TM 11-5820-890-20-2
2-158
2.2.
TROUBLESHOOTING FLOWCHARTS. Continued
Chart 43
NO RT MODULATION AT SRM FROM COMMANDER'S C 2298.
(Sheet 7 of 12)
Set up multimeter as an ac
voltmeter. Use the lowest range.
Connect meter probes between
signal line or a test point and
chassis ground. Key the handset
and whistle into the mic. Look at
the meter and note any change
in ac voltage. The change
indicates the presence of the talk
signal. The reading will be less
than 1 volt ac.
PSA J1
K
L
F
E
R
M
H
C
B
A
D
J
N
P
Z
Y
d
b
a
S
R
X
W
V
T
U
Q
P
N
M
L
K
J
F
E
D
C
B
A
G
H
PSA J2
NO
YES
OPEN
?
1. SET AM 1780 MAIN PWR TO OFF.
2. REMOVE PSA FROM MB.
3. CHECK CONTINUITY AT PSA,
J1, PIN N TO J2, PIN E.
REPLACE PSA.
REPLACE RT.
1. OBSERVE CHANGE IN AC VOLTAGE AT
PSA J1, PIN N TO PIN A (GND) (SEE NOTE).
2. PRESS PTT AND WHISTLE SHARPLY
INTO HS.
NO
YES
AC
VOLTAGE
CHANGE
?
9
SH 8
7
SH 7
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