TM 5-6675-250-20
2-8. ASSEMBLY AND PREPARATION FOR USE (Continued)
C O A R S E L E V E L i N G ( C o n t i n u e d)
c . I f t h e u n i t i s t o b e c e n t e r e d o v e r a f i x ed
reference point, extend plumb pointer (1) located
on the bottom of the GRU housing (2).
d. Place the GRU (1) on the ground so that the
pointer is close to the fixed point and press the
leg spades (2) into the ground.
e . R e l e a s e h o l d d o w n c l a m p s ( 3 ) o n t h e t r i p od
(4) and shift GRU (1) in the tripod (4) to position
pointer over the fixed reference point.
f. Rotate the theodolite alidade (5) to position
t h e o b j e c t i v e e n d o f t h e t e l e s c o p e ( 6 ) o v e r t he
NORTH mark on the GRU (1) and tighten horizon-
tal lock.
g.
Preorient the GRU (1) to north by releasing
t h e t r i p o d h o l d d o w n c l a m p s ( 3 ) a n d r o t a t e t h e
GRU (1) in the tripod (4) until the two magnetic
c o m p a s s n e e d l e i m a g e s a r e i n c o i n c i d e n c e . W i th
the telescope (6) level, depress the plunger (7) on
the magnetic compass (8).
h . C h e c k t o e n s u r e t h a t p l u m b i n g p o i n t e r i s
still over the fixed reference point. Tighten each
of the three holddown clamps (3) on the tripod (4).
i . C o n n e c t t h e i n t e r c o n n e c t c a b l e ( 1 ) b e t w e en
the ECU (2) and GRU (3).
C o n n e c t p o w e r c a b l e ( 4 ) b e t w e e n t he
POWER receptacle (5) on the ECU (2) and a 22-33
Vdc power source.
2-7
