TM 55-4920-390-13&P
5-3. CLEANING REFLECTOR . Whenever the reflector appears dirty or dingy, remove the plastic cover as in 5-2, b,
and clean the reflector using a clean cloth, cleaning tissue or similar. Water or solvent may be used, but avoid anything
that will leave an oily film. Such cleaning should be done whenever the flash tube is replaced.
5-4. FOCUSING LAMP . Periodically check focus of lamp, and when required, re-focus as in 5-2.
5-5. Lubrication is not required.
NOTE
A spare flash tube Nat. Stock No. 6240-019-5835, is kept in a plastic box secured by a clip on the
cover of the electronic section. ALWAYS replace the spare immediately after it is used. Otherwise,
the next user who needs a spare will be disappointed and this provision will have lost its value.
5-6. REPLACEMENT OF PARTS . If it
should be
determined, from tests in
Section VI, that replacement of
circuit board,
discharge capacitors, diode package, or reflector is required, proceed as follows -
5-7. REPLACEMENT OF CIRCUIT BOARD.
b) Remove five screws securing electronic compartment cover. Remove cover. (See Fig. 1-5).
c) Remove two screws holding circuit board at heat-sink end, and nut and threaded bushing from other end. (DO
NOT REMOVE threaded bushing secured to "center" of board near heat sink end.)
d) Circuit board can now be removed. "Rotate" on service loop of cables so that board is upside down over storage
e) Unsolder the 20 wires from circuit board. (Mark wires as they are disconnected to facilitate replacement.)
f) Install new circuit board.
g) Check operation of instrument per Section 6.
h) Re-paint disturbed solder joints with anti-fungus varnish as required.
i) Replace circuit board, reversing operations 5-7 a thru e.
5-4