searchlight beam in azimuth, set the azimuth engagement
which causes the searchlight to remain
lever to the horizontal (side) position to engage the
in the overdrive mode of operation
beyond the normal timing sequence.
(d) To manually position the searchlight
Do not operate the searchlight in
beam I in azimuth, set the azimuth engagement lever to
overdrive more than once in any 5-
the vertical (upward) position to disengage the azimuth
minute period of operation.
handwheel; turn the yoke manually.
(8) To place the searchlight in the overdrive
mode of operation, pull the mode SELECTOR SWITCH
on position to turn on the scale illumination lamps.
control knob outward and release it immediately. The
indicator lamp on control boxes will illuminate and the
3-5. Standby Procedure
intensity of the light beam will increase. After 17.5
The searchlight can be placed in a standby condition
seconds 2.5 have elapsed, the overdrive mode will
which will prevent emission of light from the searchlight but
automatically cut off; this action causes the indicator lamp
will allow the xenon lamp to remain illuminated. This is
to go off and the intensity of the light beam to return to
accomplished by either of the following methods:
a. Place the mode SELECTOR SWITCH at BO.
b. MT-3900A/GSS-14 (V).
b. Pull out and upward on the SEARCHLIGHT power
switch and set it to STAND BY.
Refer to TM 11-2300-351-15-3 for
3-6. Normal Stopping Procedure
Shut off the searchlight as follows: a. Pull out and
downward on the SEARCHLIGHT power switch and set it
(a) Remove the azimuth lockpin and
to OFF. The searchlight will shut off; however, the blower
release the elevation brake.
motor will continue to operate if the searchlight has been
(b) Adjust the elevation handwheel until
operating for 3 to 4 minutes or more.
the levels indicate that the searchlight is level.
(c) If necessary, loosen the elevation
To prevent xenon lamp explosion and
setscrew and set the elevation scale so that the pointer is
possible injury to personnel and
at the 000-mil mark on the elevation scale.
equipment wait until the blower motor
(d) Without moving the elevation scale,
stops before continuing to the next
tighten the elevation setscrew.
(2) Azimuth alignment. The following procedure
b. After the blower motor stops, set the main power
is required to orient the searchlight when it is used for fire
switch to OFF.
control purposes. Direction for this operation will be
received by field command.
d. Shut off the power source that supplies power to
(a) Determine the azimuth bearing of the
the searchlight. Refer to the applicable manual for proper
searchlight from information received from field command.
(b) Release the azimuth set latch and
position the azimuth scale until the azimuth pointer is at
3-7. Emergency Stopping Procedure
the mils setting representing the proper azimuth bearing.
(c) Without moving the azimuth scale,
To prevent injury to personnel due to
close the azimuth set latch.
the possibility of a xenon lamp
(3) Starting procedure.
explosion, clear all personnel away
(a) Turn the elevation brake handwheel
from the front of the searchlight.
and release the elevation brake.
In an emergency, it may be necessary to turn off the
(b) Turn the elevation handwheel to
searchlight in the shortest possible time. To do this, shut
position the searchlight in elevation.
off the power source that supplies power to the
Section III. OPERATION UNDER UNUSUAL CONDITIONS
water without damaging the searchlight internal
components. The adjustable cowling latches are used to
vary the tension on the cowling gasket which forms a
Do not operate the searchlight when
waterproof seal between the cowling assembly and the
fording through deep water.
searchlight housing assembly.
a. The tank searchlight can be forded through deep