TM 11-5855-239-23
DIRECT SUPPORT MAINTENANCE INSTRUCTIONS
information on the parts you are authorized to
3-1. Maintenance Operations
replace.
R e f e r to the maintenance allocation chart
maintenance operations you are authorized to
33. Direct Support Troubleshooting
perform. The MAC also lists the tools and test
The troubleshooting procedures in table 3-1 sup-
equipment required for DS maintenance.
plement the organizational troubleshooting pro-
Corrective action
Possible cause
Trouble
a. Image tube defective . . . . . . . . . .
a. Replace image tube (para 36).
1.
b. Defective switch . . . . . . . . . .
b. Replace switch (para 38).
image tube.
Poor image at long range . . . . . . I m a g e t u b e n o t s e a t e d p r o p e r l y
2.
Image pulsates . . . . . . . . a. Image tube defective . . . . . . . . a. Replace image tube (para 3-6).
3.
b. Image tube contact ring not making b. Remove contact ring and clean.
contact.
Bright flash in image tube or
Image tube defective . . . . . . . .
4.
sparking around edge of image.
Dirty image tube . . . . . . . . . . . . Clean image tube (para 3-6).
5.
Short viewing time . . . . . . . .
Light source failure . . . . . . . . . Defective switch . . . . . . . . . . . . Replace switch (para 3-9).
6.
High Voltage Power Supply
a. Unscrew the eyepiece counterclockwise.
a. Unscrew the switch assembly counterclock-
wise.
b. Unscrew the eyeshield and inspect the lens-
es for scratches, chips, or breaks.
b. Hold the metascope with the palm of your
hand over the open end. Tilt the metascope up
c. Clean the lenses with lens tissue or a lint-
and rap the closed end with your other hand.
free cloth. Use distilled water if necessary.
The power supply should slide free.
d. Replace the packing ring if the rubber is
c. Discharge the power supply as shown on fig-
deteriorated or damaged. Lubricate new pack-
ure 3-2.
ing ring with pneumatic grease MIL-G-4343.
d. Clean electrical contact areas, if necessary,
into the metascope
e. Screw the eyepiece
with fine abrasive paper. Wipe off with lens tis-
clockwise.
sue or a lint-free cloth.
e. Test the power supply by replacing it with
a new one.
f. Replace the
power
supply,
battery,
and
a. Unscrew the eyepiece counterclockwise.
switch assembly.