TM 5-6350-264-14&P-12
NAVELEX EE 181-AA-OMI-120/E121 C-7359-60-1
TO 31S9-2FSS9-1-12
Table 5-1. Troubleshooting Procedures - Continued
Corrective action
Probable cause
Trouble
b. If clock signal is stable, check FSK
d. (cont)
2. (cont)
signal. Set oscilloscope as follows:
@2v
volts/division
@0.1ms
time/division
@dc
input
Connect scope probe to A1-TP7,
violet. Connect scope ground to
Transmitter chassis. Ground A1-TP5
(green) by connecting a jumper
from A1-TP5 to Transmitter chassis.
The scope should display FSK signal
as a squarewave of 6 1 vdc, and
0.81 to 0.76 ms (1231.9 to 1308.1
Hz). Maintain this check for a period
of time to ensure that FSK signal is
stable.
Do NOT short A1-E14 to chassis/
ground or equipment will be damaged.
c. Disconnect jumper (between A1-TP5
and chassis) from Transmitter chas-
sis and connect it to A1-E14. The
scope should display FSK signal
as a squarewave of 6 1 vdc, and
0.96 to 0.91 ms (1037.9 to 1102.1
Hz). Maintain this check for a
period of time to ensure that FSK
signal is stable.
d. if either clock signal or FSK signal
changes, replace Data Transmitter.
(1) To remove Data Transmitter dis-
connect wires from TB6 and
TB7. Remove screws that secure
Data Transmitter to standoffs
in CU. Be careful not to drop
Transmitter inside CU. Remove
code plug from its socket on
PC board A2.
5-27
