2-28
TM 5-6675-250-20
2 - 1 0 . T R O U B L E S H O O T I N G ( C o n t i n u e d)
Table 2-3. Troubleshooting (Continued)
M A L F U N C T I ON
TEST OR INSPECTION
CORRECTIVE ACTION
GYROSCOPIC REFERENCE UNIT (GRU) (Continued)
Step 2.
Check for defective control.
a. Replace existing GRU with one that is operable. If the system
operates correctly with new GRU, this indicates original GRU was defec-
tive.
b. Replace a defective GRU (1) with a new one, by placing Mode Select
Switch (2) in PWR OFF position (3) and disconnecting and connecting
power cable (4) to GRU (1).
c.
Report defective GRU to Direct Support Maintenance.
