TM 55-4920-414-13&P
Table 4-2. Troubleshooting - Test Box (Cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 14. 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 15. Place POWER AC switch OFF.
Step 16. Connect jumper wire from pin 5 to pin 6.
Step 17. Disconnect multimeter from POSITION XDCR TRIM PISTON test jack and connect to POSITION XDCR
STICK INPUT test jack.
Step 18. 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 19. Disconnect multimeter leads.
Step 20. Place POWER AC switch OFF. Remove test cable WI.
Step 21. Make continuity check bet ween pin A of plug marked “TO TEST SET J3" and pin 2 of plug marked
“PITCH TRIM ACTUATOR.
a. If there is no continuity, replace cable (Table 4-1), paragraph 4-20.
Step 22. Make continuity check between pin B of plug marked “TO TEST SET J3" and pin 3 of plug marked
“PITCH TRIM ACTUATOR’.
a. If there is no continuity, replace cable (Table 4-1), paragraph 4-20.
7.
BOOST PRESS OFF AND/OR BOOST PRESS ON INDICATORS DO NOT GO ON.
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Connect test cable W2 to connector J3 on rear of Test Box.
Connect jumper wire between pin 1 and pin 2 on test cable plug marked “PRESSURE SWITCH”.
Place POWER DC switch ON. BOOST PRESS OFF indicator shall light green.
a. If indicator does not light, replace bulb, paragraph 4-10.
b. If indicator still doesn’t light, 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 DC switch OFF.
Disconnect jumper wire from pin 2 and connect to pin 3.
Place POWER DC switch ON. BOOST PRESS ON indicator shall light green.
a. If indicator does not light, replace bulb, paragraph 4-10.
b. If indicator still does not light, 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 DC switch OFF and remove jumper wire.
8.
VALVE CURRENT METER DOES NOT RESPOND CORRECTLY WHEN CURRENT CONTROL IS TURNED.
Step 1.
Step 2.
Step 3.
Step 4.
Connect one 1,000 ohm, 1/2 watt resistor between pins 3 and 4 and another between pins 1 and 2 on test
cable plug marked "SAS ACTUATOR’.
Place POWER AC switch ON.
Place TRIM COIL, SELECT switch to BOTH and allow 1 minute circuit warm-up time.
Turn CURRENT CONTROL to extreme position toward INCR (clockwise). VALVE CURRENT meter
shall indicate between -10.00 and -11.00 ma.
a. If meter does not indicate anything, 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.
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