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)
T a b l e 2 - 3 . T r o u b l e s h o o t i n g ( C o n t i n u e d)
M A L F U N C T I O N
TEST OR INSPECTION
CORRECTIVE ACTION
GYROSCOPIC REFERENCE UNIT (GRU) (Continued)
5 . T H E O D O L I T E I N O P E R A T I V E.
S t e p 1 . C h e c k f o r d e f e c t i v e l a m p s.
a.
b.
c .
d .
e .
f .
g .
Place MODE SELECT SWITCH (1) in PWR OFF position (2).
Turn protective cap (3) counterclockwise and remove.
Remove lamp (4) from socket.
Inspect lamp for burned out filament.
Replace defective lamp with a good one.
Install lamp (4) in socket.
Install protective cap (3) finger tight.
2-27
