TM 11-5841-287-30
Table 3-1. Encoder an Data Link Control Functional Test
Control Settings
Test
Equipment
Step
Equipment
under test
Performance Standard
POWER switch
Same as above
Indicator lamps sequence is as follows
XMT
1.RT FAULT, ENCODER FAULT, and BITE
DOWNLINK
IN PRCS lamps illuminate
BITE switch
2.RT FAULT and ENCODER FAULT lamps
3.RT FAULT lamp illuminates m approx.-
Press down
go off in approximately 3 seconds
mately 3 seconds
4
Depress
Observe BITE IN PRCS indicator lamp
BITE IN PRCS indicator lamp is extinguished
RT
DOWNLINK
on data link control
FAULT remains lluminated
BITE switch
5
POWER
POWER switch
Disconnect test setup
None
switch
OFF
OFF
Table 3-2. Encoder and Data Link Control Troubleshooting
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
WARNING
DANGEROUS VOLTAGES EXIST IN THIS EQUIPMENT Be careful when working around the 115-volt ac lne-
to-neutral connections
1.
ENCODER FAN AND ELAPSED TIME METER DO NOT OPERATE ENCODER FAULT LIGHT NOT LIT
(Data link control POWER switch Is In STBY or XMIT)
Step 1. Check for 28 + volts dc at fuse test point on encoder front panel
(a) Voltage present. Go to step 3.
(b) Voltage absent Set UKM-4 POWER switch to OFF Replace fuse Set UKM-4 POWER switch to ON If fuse blows, go to step 5. Voltage
absent and fuse is good, go to step 2.
Step 2 Disconnect 2J2 Check for 28 _ 2 volts dc between pins D and C of UKM-4 cable connector
(a) Voltage not correct Refer to TM 11-6625-2937-13, Test Set, Electronles Systems ANfUKM-5 Check UKM-5 output voltage
(b) Voltage correct Set UKM-4 POWER switch to OFF Remove encoder 2FL1 (para 3-16) Refer to figure 3-4, sheet 7 Isolate faulty component
or wiring Repair or replace components as necessary
Step 3 Set UKM-4 POWER switch to OFF Disconnect 2P4 from 2FL1-J 1 Set POWER switch to ON Measure 28 + 2 vdc betw, pins 2FL1-J1, pin
8 (+)and 2FL1-J1, pin 7 (gnd)
(a) Voltage present, go to step 4.
(b) Voltage incorrect Set UKM-4 POWER switch to OFF Remove 2FL1 (para 3-16) Using figure 3-4, sheet 4, isolate faulty component or wiring
Repair wiring or replace faulty component as necessary
Step 4 Set UKM-4 POWER switch to OFF Using point-to-point diagram below and ohmmeter, isolate faulty component or wiring Repair wiring or
replace components as necessary
3-3
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