TABLE 4-2. TROUBLESHOOTlNG CHART (Continued)
Probable Cause
Step
Corrective Action
Symptom
Replace cable
c.
Defective video cable C147363
13
c.
(cont'd)
d.
d. Broken wire on Pushbutton Board Assy
1A3
Defective switch 1A3S1
e.
e.
No external pulse
14
Same as Step 12
Same as Step 12
modulation
Defective Modulator MD-1075/URM
Replace Modulator MD-1075/URM
15
a.
a.
N O internal FM operation
(AN/URM-206)
Defective video cable C147363
b.
b. Replace cable
(between FM OUT and EX FM
connectors)
c.
c.
d.
Defective switch 1A3S1
d.
Broken wire on Pushbutton Board
e.
Assembly 1A3
Defective amplifier circuit (1A3Q1
a.
No internal FM
16
a.
(Model SG-1145/URM)
b. Replace
b. Defective switch 1A3S1
No ac voltage between pin 2 of
Replace
c.
c.
1A3U2 and ground
d. Broken terminal T3, T4, and T5
on Pushbutton Board Assy 1A3
e. Defective in FM DEV potentiometer
e.
1A3R16