C6, TM 9-2350-230-12
Table 5-1. Troubleshooting-Continued
Malfunction
Probable cause
Corrective action
CAL 5O MACHINE GUN,M2
45.Failure to lock - Continued
b.
Insufficient headspace
b.
46.Failure to fire
a.
a.
b.
Incorrect timing
b.
47.Failure to extract
a.
Dirty chamber
a.
Clean.
b.
Broken extractor
b.
Replace bolt assembly.
48.Failure to cock
a.
Broken sear
a.
Replace bolt assembly.
b.
Worn sear notch
b.
Replace bolt assembly.
c.
Weak sear spring
c.
Replace bolt assembly.
d.
Worn hooked notch on firing pin
d.
Replace bolt assembly.
extension.
49.Failure to eject
a. Defective ejector
a. Replace bolt assembly.
b. Obstructed T-slot in bolt assembly
b. Remove obstruction.
M37, M47 AND M48 PERISCOPES
50. Poor visibility
a. Dirty optical surface
a. Clean optical surfaces with lens
b. Refer to TM 750-116
M48 PERISCOPE
a. Periscope power switch not on
a. Check power switch on periscope
b. Weak or dead cell if operating from
battery.
NOTE. Place the positive tip of
the cell In housing first.
c. Check target area with another IR
viewing instrument .
52. No fluid from periscope washer
a. No fluid in reservoir
assembly
b. Clogged tubing
b. Clean tubing or nozzle.
53. Periscope loose after installa-
Loose mount assembly
Tighten mount assembly bolts (2-12).
tion.
54.Flickering infrared image
a. Loose or poor connection
b. Report condition to organizational
maintenance personnel.
XM44 SERIES PERISCOPE
55.Loss of boresight
Boresight knobs not fully engaged
Check knobs to insure firm engagement
a. Periscope power supply ON, OFF
a. Turn power supply switch to ON
switch in OFF position
b. Defective lamp)
c. Loose or broken connection
c. Check all connections on control panel.
5-6