TM 55-4920-414-13&P
Table 4-2. Troubleshooting - Test Box (Cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
b. If reading is out of tolerance, send Test Box to higher maintenance.
Step 5. Turn CURRENT CONTROL to extreme position toward DECR (counterclockwise). 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.
b. If reading is out of tolerance, send Test Box to higher maintenance.
Step 6. Place TRIM COIL SELECT switch to 1. VALVE CURRENT meter shall indicate between +06.50 and
+07.50 ma.
a. If reading is out of tolerance, send Test Box to higher maintenance.
Step 7. Turn CURRENT CONTROL to extreme position toward INCR. VALVE CURRENT meter shall indicate
between -06.50 and -07.50 ma.
a. If reading is out of tolerance, send Test Box to higher maintenance.
Step 8. Place TRIM COIL SELECT switch to 2. VALVE CURRENT meter shall indicate between -06.50 and
-07.50 ma.
a. If reading is out of tolerance, send Test Box to higher maintenance.
Step 9. Turn CURRENT CONTROL to extreme position toward DECR. VALVE CURRENT meter shall indicate
between +06.50 and +07.50 ma.
a. If reading is out of tolerance, send Test Box to higher maintenance.
Step 10. Place POWER AC switch OFF.
Step 11. Disconnect and stow all cables.
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