TM 55-4920-414-13&P
Table 4-2. Troubleshooting - Test Box
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1.
2.
3.
4.
POWER DC INDICATOR AND/OR MULTIMETER INDICATIONS NOT CORRECT WITH POWER DC SWITCH
ON AND TRIM SWITCH ON.
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Place POWER DC switch OFF.
Connect multimeter between pins 1 (+) and 2 (-) of cable plug marked “TO J466R".
Place TRIM switch ON.
Push in POWER DC circuit breaker.
Place POWER DC switch ON. POWER DC indicator shall light green and multimeter shall indicate 28 vdc.
a. If both indications are incorrect, check dc input power cable (Table 4-1 ).
If cable is good, send Test Box to higher maintenance.
If cable is not good, replace cable, paragraph 4-20.
b. If POWER DC indicator is on but multimeter indication is incorrect, send Test Box to higher
maintenance.
c. If multimeter indication is correct but POWER DC indicator is off, replace bulb, paragraph 4-10.
Place TRIM switch OFF. Multimeter shall indicate O vdc.
a. If multimeter does not indicate O vdc, send Test Box to higher maintenance.
MULTIMETER DOES NOT INDICATE DC LINE VOLTAGE WITH SAS SWITCH OFF.
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Place POWER DC switch OFF.
Connect mulitmeter between pins 1 (+) and 2 (-) of cable plug marked “TO J468R".
Place SAS switch OFF.
Place POWER DC switch ON. Multimeter shall indicate 28 vdc.
a. If multimeter does not indicate 28 vdc, send test box to higher maintenance.
Place SAS switch ON. Multimeter shall indicate O vdc.
a. If multimeter does not indicate O vdc, send to higher maintenance.
MULTIMETER DOES NOT INCLUDE DC LINE VOLTAGE WITH BOOST SWITCH OFF.
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Place POWER DC switch OFF.
Connect multimeter between pins 1 (+) and 2 (-) of cable plug marked “TO J469R".
Place BOOST switch OFF.
Place POWER DC switch ON. Multimeter shall indicate 28 vdc.
a. If multimeter does not indicate 28 vdc, send test box to higher maintenance.
Place BOOST switch ON. Multimeter shall indicate O vdc.
a. If multimeter does not indicate O vdc, send to higher maintenance.
SAS PRESS OFF AND/OR SAS PRESS ON INDICATOR DO NOT COME ON.
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Place POWER DC switch OFF.
Connect jumper wire between pins 1 and 2 of cable plug marked “TO J467R".
Place POWER DC switch ON. SAS PRESS OFF indicator shall light green.
a. If SAS PRESS OFF indicator does not light, replace bulb, paragraph 4-10. If indicator still doesn’t
light, send test box to higher maintenance.
Place POWER DC switch OFF.
Remove jumper lead from pin 2 and connect to pin 3.
4-3
