TM 55-4920-414-13&P
Table 4-2. Troubleshooting - Test Box (Cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 6. Place POWER DC switch ON. SAS PRESS ON indicator shall light green.
a. If SAS PRESS ON indicator does not light, replace bulb, paragraph 4-10. If indicator still doesn’t light,
send test box to higher maintenance.
Step 7. Remove jumper wire.
5.
POWER AC INDICATOR DOES NOT LIGHT WITH POWER AC SWITCH ON.
Step 1. Place POWER DC switch OFF.
Step 2. Push in POWER AC circuit breaker.
Step 3. Place POWER AC switch ON. POWER AC indicator shall light red.
a. If POWER AC indicator does not light, replace bulb, paragraph 4-10.
b. If indicator still doesn’t light, check ac input power cable (Table 4-1). If cable is not good, replace
cable, paragraph 4-20. If cable is good, send Test Box to higher maintenance.
Step 4. Place POWER AC switch OFF. POWER AC indicator goes off.
a. If indicator stays on, send Test Box to higher maintenance.
6.
MULTIMETER INDICATIONS OF +15 VDC AND/OR -15 VDC NOT PRESENT WITH POWER AC SWITCH ON.
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Step 8.
Step 9.
Connect multimeter between +15 VDC and SIG GRD test jacks.
Place POWER AC switch ON. Multimeter shall indicate between +14.5 and +1 5.5 vdc.
a. If multimeter indication is not correct, send Test Box to higher maintenance.
Connect multirneter between -15 VDC and SIG GRD test jacks. Multimeter shall indicate between
-14.5 and -15.5 vdc.
a. If multimeter indication is not correct, send Test Box to higher maintenance.
Place POWER AC switch OFF. Connect test cable W 1 to receptacle J3 on rear of Test Box.
Connect multimeter between pin 4 on test cable plug marked “PITCH TRIM ACTUATOR” and Test Box
SIG GND test jack.
Place POWER AC switch ON. Multimeter shall indicate between +14.5 and +15.5 vdc.
a. If mulitmeter indication is not correct, check cable (Table 4-1). If cable is not good, replace cable,
paragraph 4-20. If cable is good, send Test Box to higher maintenance.
Place POWER AC switch OFF. Disconnect mulitmeter from pin 4 and connect to pin 7.
Place POWER AC switch ON. Multimeter shall indicate between+ 14.5 and +15.5 vdc.
a. If multimeter indication is not correct, check cable (Table 4-1). If cable is not good, replace cable,
paragraph 4-20. If cable is good, send Test Box to higher maintenance.
Place POWER AC switch OFF. Disconnect multimeter from pin 7 and connect to pin 8.
Step 10. Place POWER AC switch ON. Multimeter shall indicate between -14.5 and -15.5 vdc.
a. If multimeter indication is not correct, check cable (Table 4-1). If cable is not good, replace cable,
paragraph 4-20. If cable is good, send Test Box to higher maintenance.
Step 11. Place POWER AC switch OFF. Disconnect multimeter from pin 8 and connect to pin 5.
Step 12. Place POWER AC switch ON. Multimeter shall indicate between -14.5 and -15.5 vdc.
a. If multimeter indication is not correct, check cable (Table 4-1 ). If cable is not good, replace cable,
paragraph 4-20. If cable is good, send Test Box to higher maintenance.
Step 13. Place POWER AC switch OFF. Disconnect multimeter from pin 5 and connect to test box POSITION
XDCR TRIM PISTON test jack. Connect jumper wire from pin 5 to pin 9.
4 -4
