TM 9-1240-382-34
TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1.
LOSS OF BORESIGHT
Step 1. Ensure that boresight knobs are fully
engaged with their positive clutches.
a. If a knob cannot be engaged, repair
b. If boresight knobs operate properly,
proceed to step 2.
Step 2. Ensure that the elbow assembly is
properly seated in the head.
a. Remove the elbow assembly and
check for foreign matter around locating pads or
for work or damaged catches or strikes, and
replace, clean or repair as necessary (p 2-9 - 2-
b. If boresight capability is not restored,
replace head or elbow assembly as required.
2.
POOR OR NO ILLUMINATION OF NIGHT RETICLE
NOTE
Cover objective lens and apply 24 volts dc
power to the elbow assembly.
Step 1. Ensure that RETICLE control knob is properly adjusted.
a. Operate RETICLE control knob.
b. If reticle cannot be lighted, proceed to step 2.
Step 2. Check for damaged or defective incandescent lamp or
lampholder.
b. If lampholder is defective, replace lampholder (p 2-10-2-11).
c. If lamp and lampholder are satisfactory, proceed to step 3.
Step 3. Ensure that contact is not corroded.
a. If contact is corroded, clean the contact. (p 2-10).
b. If contact is not defective, proceed to step 4.
Step 4. With objective lens covered to simulate
darkness, move shutter switch to the ON
position (reset if necessary) and operate
TUBE control knob.
a. If image intensifier tube lights,
replace RETICLE variable resistor (p 2-12-2-15).
2-2
