TM 9-1240-400-34&P
Section III. TROUBLESHOOTING
3-6.
TROUBLESHOOTING PROCEDURES.
a. The symptom index can be used as a quick guide to troubleshooting. Common malfunctions are listed in
alphabetical order with a page number reference to the troubleshooting table, where a test or inspection and corrective
action are provided.
b. There are no direct support troubleshooting instructions. The general support troubleshooting table lists the
common malfunctions which may be found during maintenance of the M139 elbow telescope. Refer to page 3-4. Perform
the tests/inspections and corrective actions in the order listed.
c.
This manual cannot list all malfunctions that may occur, nor all tests or inspections and corrective actions.
GENERAL SUPPORT SYMPTOM INDEX
Troubleshooting
Procedure
(Page)
M139 ELBOW TELESCOPE
Is not collimated .................................................................................................................................................. 3-4
Has moisture or foreign matter ........................................................................................................................... 3-4
EYEPIECE ASSEMBLY
Has moisture, foreign matter, or is chipped ........................................................................................................ 3-4
RETICLE CELL ASSEMBLY
Has moisture or foreign matter ........................................................................................................................... 3-5
Does not illuminate ............................................................................................................................................. 3-5
COVER ASSEMBLY
Is not secured properly
Plate is not legible............................................................................................................................................... 3-6
OBJECTIVE CELL ASSEMBLY
Has moisture or foreign matter ........................................................................................................................... 3-6
Parallax exceeds 0.1 mil at 125 meters .............................................................................................................. 3-6
3-3
