Boeing SPECTROLAB SX-16 Nightsun User manual

SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
5.18.5 Cooling Blower
The Searchlight will rapidly overheat without the blower operating potentially damaging the entire
Searchlight. Operation of the Searchlight without the blower should only be considered in critical
emergency situations. Even then, operation should be limited to 60 seconds at a time within a 10
minute period. Even with this limited duty cycle, the Searchlight probably will suffer internal damage,
which can be very expensive to repair. In a life critical emergency, the choice to operate the
Searchlight is a choice that the operating crew must make.
NOTICE
Reliable operation of the blower is vital to the performance and service life of
the Searchlight. If the blower does not operate, it must be repaired or replaced
immediately.
5.18.5.1 Audible Inspection (Daily)
Conduct daily inspections of the blower while the Searchlight is completely assembled and installed
on the aircraft.
•The aircraft engine should not be running during the inspection so that you can hear the
blower. Instead, operate the blower using the aircraft battery or a quiet auxiliary power unit
(APU).
•Place the Start/On/Off switch in the On position to turn on the Searchlight blower.
oThe blower should start rapidly and run smoothly. It should come up to full speed
within 2 seconds and sound smooth and even. Let the fan run for 10 to 15 seconds to
be sure that it runs smoothly.
oIf the blower takes longer than 2 seconds to run at full speed, either the wiring or the
blower itself may be faulty and must be checked.
oAny change or unevenness in the tone or pitch of the blower may indicate bad
bearings or brushes. If the blower does not operate smoothly, it must be removed
and replaced.
•Turn the Start/On/Off switch to the Off position. The blower should coast smoothly to a stop in
a few seconds.
5.18.5.2 Removal of the Rear Cover
Place the Searchlight on a workbench during this procedure for ease of blower removal and
replacement.
•If the Searchlight must remain on the aircraft, place the Searchlight in a horizontal position,
and remove the power cable.
•If the Searchlight will be on a workbench, clean the top of the workbench, and place a soft
material on top of the bench. Position the Searchlight so that it rests on the window
assembly. The rear cover should be approximately at shoulder height. Remove the power
cable.
DANGER!
The arc lamp contains pressurized xenon gas at
approximately 85 to 90 psi at room temperature and
up to 370 psi at full operating temperature.
If the lamp is mishandled, it can explode and send
hot, sharp shards of quartz at high-speed in every
direction. These shards can cause serious bodily
injury.
To reduce the risk of serious injury:
•Remove power from the Searchlight so it
cannot be turned on during maintenance with
front glass removed.
Source: Spectrolab, Inc. 84
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
•Only trained personnel should remove
window assembly.
•Wear full protective gear that includes safety
glasses or full face mask, long-sleeve jacket,
and sturdy gloves.
•If Searchlight has been operating recently, let
it cool to room temperature before exposing
lamp.
•Never leave exposed xenon lamp unattended.
Remove the rear cover of the Searchlight.
•To remove the rear cover assembly (and trim ring if there is one), remove the four Phillips
pan-head screws that hold the cover in place. The screws are located around the perimeter
of the rear housing (Figure 39). As you remove the screws, the rear cover may pop out from
the housing as far as ½” (1.5 cm). This is normal and is caused by spring forces in the
reflector’s three return springs.
•Remove the trim ring (if applicable).
•If the internal springs do not force the rear cover off, hold the Searchlight housing with one
hand and pull the rear cover off with the other. Sometimes it takes considerable force to
remove the cover if there is corrosion on the housing or cover. Be careful not to damage the
wires that connect the rear cover to the rest of the Searchlight.
•Remove the Molex®connector that supplies power to the rear cover assembly (Figure 41).
•Place the rear cover on a workbench with the handle resting on the bench top. Place a
cushion, such as a soft clean rag or paper, underneath the cover to protect it from scratches
and keep it from rocking and wiggling as you work.
Source: Spectrolab, Inc. 85
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
Figure 41 Rear Cover Assembly Internal Components
Figure 42 Enhanced Rear Cover
5.18.5.3 Detailed Inspection (24 Months)
NOTICE
Disassembly of the blower is delicate work and should only be performed by
personnel experienced in small electric motor repair work.
The blower manufacturer does not recommend or support field disassembly or
motor repairs.
Source: Spectrolab, Inc. 86
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
Every 24 months or 1,200 flight hours or 500 operating hours, conduct a detailed inspection of the
blower.
•Loosen and remove the two screws that hold the blower end cover in place (Figure 41).
Remove the sheet metal cover from the end of the blower motor and feed it gently over the
power wires that lead to the bracket with the Diode and terminal posts.
•Inspect the blower (fan) to make sure that it is not frozen in place (the salt coating from use at
sea can cause this).
•Check the housing for signs of cracks.
•Check all electrical connections to ensure that they are intact.
5.18.5.4 Blower Replacement
WARNING!
Fan blades immediately rotate at high-speed
(15,000 rpm) when power is applied.
•Blades cause serious injury to fingers if
fingers touch rotating fan blades.
•Small objects can be sucked into fan
blades and be ejected at high-speed and
become eye and skin hazards.
To avoid injury:
•Do not touch blades.
•Wear eye protection.
•Keep work area clear of small loose
objects.
To replace the blower:
•Remove the Searchlight rear cover.
•Take notes, pictures, or draw a sketch to record which motor wires (by color) are connected
to which terminal posts.
•Unsolder the motor wire connections that attach to the Diode and terminal posts on the
bracket (Figure 41).
•Clip off the Ty-Wrap®wire ties to free the motor wire so that it can be removed after it is
unsoldered.
•Remove the screws from the motor mounting clips. Then remove the clips to remove the
blower motor from the rear cover assembly.
•Replace the old blower motor with a new unit. Replace the mounting clips and screws.
•Connect the wires from the new motor to the terminal posts on the bracket. To do this:
•Wrap the connections first, and then solder them.
•Remove excess flux from the solder joint after it is cool.
•Bundle the wires and attach Ty-Wrap®ties to hold the wires in place as they were before they
were removed.
•Connect the Molex®connector to supply power to the rear cover assembly.
Source: Spectrolab, Inc. 87
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
•Place the Start/On/Off switch in the On position to turn on the Searchlight blower. Verify that
the fan operates smoothly and rotates in the proper direction (in the direction of the arrow on
the motor housing).
•Place the Start/On/Off switch in the Off position to turn the blower off.
•Listen carefully to verify that the large relay (contactor K1) in the Junction Box opens as soon
as the power is turned off.
•If the motor’s positive (+) wire is not connected properly to the Diode on the bracket (Figure
41), contactor K1 will not open until the fan coasts to a stop (in 3 to 5 seconds).
•Before you re-install the rear cover assembly, conduct the focus motor and cam inspection.
5.18.5.5 3 Month Test of Focus Motor and Cam
The focus motor and cam are robust, but routine inspection and maintenance will help to ensure long
component life and reliable operation.
•Daily (or preflight) test the operation.
•Every 3 months or 100 flight hours or 50 operation hours, conduct a functional test of the
focus motor and cam, and conduct an interior inspection of the focus motor and cam with the
rear cover removed.
5.18.5.6 Preparation
Make the adjustments in this section using one of the following targets:
•A target that is 10 meters (33 feet) away. It should be dark or medium dark in color,
completely non-flammable, and heat-resistant to temperatures up to 500° F (260° C). The 10
meter test, however, is not as accurate as a 100 meter test.
•A target that is 100 meters (326 feet) away. It can be on the plain side of a building (interior or
exterior) or a hangar door. The target can be any color, but it should be non-flammable and
heat-resistant to temperatures of 160° F (70° C).
5.18.5.7 Functional Test
WARNING!
Xenon arc Searchlights produce a high-intensity light
beam during operation.
If the beam is directed into the eyes at close range, it can
cause permanent eye damage in a fraction of a second.
The ultraviolet rich beam can cause severe sunburn to
unprotected skin.
The beam also can set on fire nearby combustible
objects, including clothing and hair.
To reduce the risk of serious injury or fire:
•Never look directly into Searchlight during
operation.
•Do not expose people to light beam.
•Never walk through the light beam.
•Alert all nearby people that the Searchlight will
be operating.
•Always wear protective eyewear when looking at
objects illuminated by nearby Searchlight.
•Before starting Searchlight, make sure it points
down and not toward any objects that may be
damaged by light beam.
Source: Spectrolab, Inc. 88
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
•Keep all flammable objects away from the light
beam.
During close up inspection and cleaning activities, the
Searchlight must not be turned on. Remove the Control
Box or its cable, or disconnect the Searchlight cable so
the light cannot be turned on accidentally during the
inspection.
Conduct the following operational test of the focus mechanism:
•Place the Start/On/Off switch in the On position to turn on system power, and use the
Down/Up/Left/Right directional control to point the Searchlight toward the target.
•Place the Start/On/Off switch to the Start (up) position, and hold it in this position until the
lamp starts.
•Press the Focus button to complete the following tests:
oVerify that the beam diameter changes smoothly when the focus motor is operating.
If the motion is jerky, components could be worn out, loose, require cleaning, or
require lubrication. To examine these components, you will have to remove the rear
cover.
oVerify that 10 seconds are required to run through an entire focusing cycle, with the
beam cycling from wide to narrow and back to wide (or narrow to wide to narrow).
This indicates that the focus motor is operating properly and that the cam is not
slipping on the shaft.
oVerify that the beam changes from a minimum diameter of 2° to 4° to a maximum
diameter of 18° to 22°.
•Place the Start/On/Off switch to the Off position to turn the system off. Then immediately
place the switch in the On position to turn the fan on to cool the Searchlight.
5.18.5.8 Interior Inspection (24 Months, 1200 Flight Hours, 500 Operation Hours)
With the rear cover assembly still removed, make the following observations:
•Verify that the focus cam set screw is tight on the focus motor shaft.
•Verify that the fasteners holding the focus motor to the rear cover are tight.
•Verify that the rear cover is not dented in the area directly behind the focus cam. A dent can
interfere with the operation of the focus cam.
•Examine the motor wiring and the Molex®connector to make sure it is in good condition (not
frayed, worn, or broken). Repair or replace these as necessary.
•Examine the focus motor’s brush holder for signs of rust or dirt. If they are dirty or rusted,
clean them with alcohol.
•Apply a 28 volt DC power source to the focus motor. Verify that it rotates smoothly and takes
approximately 10 seconds for one revolution (focusing cycle).
•Apply some resistance to the cam to slow its rotation. The motor should slow down slightly
under moderate resistance. If the motor does not work or stalls easily during this test, it
should be replaced. The motor usually fails because of rust; therefore, it cannot be repaired.
•Lubricate the focus cam with a light coating of medium-viscosity, heat-resistant grease. Dow
Corning Molycote®44 is recommended for this.
•Re-install the rear cover assembly.
5.18.5.9 Rear Cover Installation
After the fan motor, focus motor, and focus cam inspections are complete, replace the rear cover
assembly and trim ring (if applicable).
•Connect the Molex®connector on the rear cover assembly to the connector for the
Searchlight (Figure 41).
Source: Spectrolab, Inc. 89
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
•Position the rear cover so that the fan filter cover is toward the top of the Searchlight (the rear
cover only fits onto the Searchlight housing one way). Slip the trim ring (if there is one) over
the cover.
•Align the holes on the rear cover with those on the housing. It may help to insert a pointed
alignment tool (such as a scratch awl) through a hole to align the cover with the housing and
hold it in place. Insert a screw into that hole and turn it a few turns, but do not tighten it fully.
•Press the rear cover down to overcome the spring tension. As you push the cover closed, the
remaining screw holes will come into alignment. Install the remaining screws in the remaining
holes without tightening them completely.
•Partially tighten all of the rear cover screws in preparation for a final fine focus adjustment.
•Re-install the Searchlight on the aircraft if it has been removed.
•Perform the focus adjustment. If necessary, follow the additional instructions in the Final Fine
Focus Adjustment with Rear Cover On section.
•Record the results
5.19 Mechanical Housing Inspection
WARNING!
Cracks around housing boss welds can cause housing
structural failure.
High vibration
or flexing can cause cracks in the
Searchlight housing near mounting bosses. If cracks are
extensive, Searchlight can break loose during flight.
Parts of the Searchlight can fall to ground and cause
serious injury, or severe damage to aircraft. .
To reduce the risk of serious injury or damage:
•Inspect housing bosses for cracks
•Do not fly aircraft if Searchlight housing has
cracks.
•Remove Searchlight with cracked housing from
service immediately upon discovery.
•There is no approved procedure to repair broken
housing welds.
5.19.1.1 Searchlight Safety Cable Bolt
There is a boss and insert for the Searchlight safety cable bolt located at the top of the Searchlight
housing (it has a ¼”-20 thread). Inspect the bolt and the insert every 3 months or 100 flight hours or
50 operation hours.
5.19.1.2 Weld Tests for Drive and Support Bosses
The bosses are contoured, machined, aluminum round bar stock, and they are arc welded to the
outside of the spun aluminum Searchlight housing. Both of the elevation bosses have a 5/16”-24
threaded locking HeliCoil®insert in the center. They also have a four-hole pattern of #6-32 screws on
a 1-1/16” diameter circle that is used to attach the elevation stop and spacer adapters.
With vibration and age, the bosses develop a variety of wear types. These include (1) metal fatigue
and cracking at the welds and (2) deformation of the metal around the screw holes, which causes the
screws to become loose. It is necessary to conduct visual inspections of the bosses according to
schedule. If you observe any sign of fatigue failure, replace the housing immediately.
Source: Spectrolab, Inc. 90
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
5.19.1.3 Boss to Housing External Weld Exam (3 Months)
This visual examination of the boss to housing external welds is conducted while the Searchlight is
installed on the aircraft. It takes place every 3 months or 100 flight hours or 50 operation hours. To
conduct this examination:
•Thoroughly wash the Searchlight and Gimbal with a warm soap and water solution; pay
particular attention to the housing boss areas. Dry it completely.
•In a well-lit location outdoors or using a strong handheld light indoors:
•Examine the edges of the drive boss welds. Pay particular attention to the area where the
weld fillet meets the housing. Look for any sign of cracking paint or cracks in the metal.
•Look for places where water (from the washing process) is seeping out of cracks in the paint
or metal.
•Try to wiggle the housing to see if it flexes too easily.
•If you discover any cracks or suspect that there are cracks, remove the Searchlight from the
aircraft and replace the housing.
5.19.1.4 Test of Wing Bolt Housing Boss Inserts
Each elevation boss has a 5/16”-24 threaded locking HeliCoil®insert. The Wing Bolts that hold the
Searchlight in place in the Gimbal screw into these HeliCoil®inserts. When they are new, the inserts
resist the tendency of the Wing Bolts to unscrew as a result of flight vibration. As the inserts become
worn from use over time, the locking feature can become ineffectual. As a result, the threads can
become damaged or galled. This causes the Wing Bolts to become difficult or impossible to install.
This examination takes place every 6 months or 300 flight hours or 100 operation hours or each time
the Wing Bolts are removed. To conduct this examination:
•When the inserts and Wing Bolts are in good condition, you can tighten the Wing Bolts by
hand until they are fully inserted. This requires approximately 2-1/2 to 3 turns for insertion.
•The inserts and Wing Bolts must be replaced if:
oThe Wing Bolts can be screwed in using just fingertips (this means that they are too
loose).
oThe Wing Bolts require a wrench to screw them in the required number of turns (this
means that the threaded insert or the Wing Bolt threads are damaged).
5.19.1.5 Test of Elevation Stop and Adapter Plate Threaded Holes
On the ends of the mounting bosses (on the Searchlight) on each side are four #6-32 internally
threaded screw holes that are equally spaced around a 1.062” diameter bolt circle that is centered on
the threaded locking Heli-Coil inserts.
•The flathead #6-32 screws that attach the elevation stop (on the drive side) and the adapter
plate (on the non-drive side) to the bosses should tighten fully. Furthermore, when Loctite®is
used on the screws during installation, the screws should remain tight.
•If the screws are properly tightened, the elevation stop will remain fixed with respect to the
boss when the housing is pushed with enough force to slip the elevation Gearbox clutch to
drive the elevation stop against its mechanical limits (against the screw heads or drive pins).
•If the #6-32 screws do not tighten properly or will not remain tight, this may indicate damage
to the threaded holes.
5.19.1.6 On-Aircraft Test
The on- aircraft examination is recommended to take place every 3 months or 100 flight hours or 50
operation hours. To conduct this examination:
•With a pencil, make a thin mark on an exposed edge of the elevation stop and continue this
line onto the adjacent part of the side of the elevation drive boss. This pencil line will be used
to visually verify that the elevation stop does not rotate in relation to the drive boss during the
next part of this test.
•With the Searchlight turned off and pointing downward at about a 45° angle, grasp the front
and rear of the Searchlight housing. Manually rotate the Searchlight in an upward direction.
This will cause the elevation clutch to slip.
Source: Spectrolab, Inc. 91
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
oObserve the pins or screw heads that act as mechanical stops (limits) for the
elevation stop plate as they make contact at the limit of travel. The screw head or pin
that limits motion as the Searchlight moves upward is called the upper stop. This limit
is not precise. If a different elevation stop (plate) is used, the limit will be different.
•At the moment when the upper elevation stop pin or screw head is contacted by the elevation
stop plate, observe the pencil mark that you made. The line should remain straight during this
contact.
•If the pencil line develops an offset at the joint where the parts meet, it indicates that the stop
is moving and that the screws are not tight (or something else is wrong). Immediately remove
the Searchlight from the Gimbal and perform the off-aircraft inspection.
•Repeat this observation moving the Searchlight all the way to its maximum downward
elevation.
•Observe the pins or screw heads as they make contact with the stop plate at the downward
limit of travel. The line should remain straight during this contact.
•If it develops an offset at the joint where the parts meet, it indicates that the stop is moving
and that the screws are not tight (or something else is wrong). Immediately remove the
Searchlight from the Gimbal and perform the off-aircraft inspection.
5.19.1.7 Off-Aircraft Test
If the pencil mark has developed an offset during the elevation test in upward or downward directions,
conduct the following examination with the Searchlight removed from the aircraft (off aircraft
inspection):
•Remove the Searchlight from the aircraft.
•Try to tighten the four #6-32 flathead screws that hold the elevation stop onto the boss. If they
are not fully tight, try to tighten them fully to see if the threads hold.
oIf the threads hold, they are probably in good condition. Remove the screws, and
reinstall them using Loctite®(as explained below).
oIf the threads do not tighten and hold, the internal threads may be damaged and
need further inspection. First, remove the screws and then examine both the screws
and the internal threads in the boss. If a screw is stripped, replace it and observe its
installation to determine if it remains tight. If it remains tight, it can be reinstalled
using Loctite®(as explained below). If the internal threads are damaged, however,
there is no repair procedure, and the housing must be replaced. Similarly, if a screw
has been sheared off while screwed in, you can try to remove it with a screw
extractor, but this is a delicate operation and may not succeed.
If the internal threaded holes become damaged during a screw extraction procedure, you must
replace the housing because there is no repair for damaged internal threads.
•To install the screws using Loctite®, remove them one at a time. Then put a drop of Loctite®
on the threads of each screw (one at a time), and replace the screws and tighten them fully.
5.19.1.8 Elevation Stop Internal Square Drive and Stop Hardware
The internal drive hole of the elevation stop, as shown in the Elevation Motion Stop section, should be
inspected for wear and tightness every 6 months or 300 hours or 100 operation hours. These
inspections should take place with the Searchlight removed from the Gimbal. Spectrolab provides
several types of elevation stop and each one limits Searchlight motion in different ways for different
applications.
All Spectrolab stops, however, have the following characteristics:
•Square hole of 0.437” for insertion of the elevation Gearbox shaft that drives the Searchlight
up and down.
•Thickness of 0.125” and have been machined from 4130 steel that is heat treated and plated
with a rust resistant coating.
If the Searchlight has an aftermarket stop replacement, it is not addressed in this manual. These
aftermarket stops can often be identified because they may have the following characteristics:
Source: Spectrolab, Inc. 92
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
•May be made of non-magnetic stainless steel, have variable or stepped thickness, and be
thinner than 0.125” thick.
•Some have magnets, limit switches, or optical sensors attached.
5.19.1.9 Internal Square Drive Hole
The internal square hole in the elevation stop measures 0.437” ± 0.001” in each direction. It should
slip over the elevation Gearbox shaft with a snug fit. Most of the wear in the square hole should occur
immediately next to (just inboard of) the corners. To inspect the hole for wear:
•Remove the Searchlight from the Gimbal.
•Measure the inside dimensions of the hole with calipers. Each 0.001” of wear or deformation
of the hole adds approximately ¼ of a degree of play to the Searchlight elevation motion.
oAt a narrow focus with a beam diameter of 4°, the amount of acceptable play is
generally considered to be 1° or 2° (but there is no fixed rule about what is a
maximum acceptable amount of play).
oIf the square hole has been enlarged by more than 0.008” beyond its designed
0.437” (which changes the dimensions of the hole to 0.445”), replace the stop
because the amount of play would be approximately 2°.
oElevation stops are not repairable.
oIf an aftermarket stop is installed, the criteria may be the same for determining if it is
worn out as for the original equipment. Obtain information about repairing or
overhauling a stop from the supplier or manufacturer of the stop.
•To replace the stop:
•Remove all four screws that attach the stop and pull off the old stop.
•Install a new stop, and position it in the same orientation as the old one.
•Place a drop of Loctite®on the screws and fully tighten them.
5.19.1.10 Alignment and Contact
CAUTION!
Elevation stops must work properly for safe
Searchlight operation. If not functioning properly:
Searchlight beam can shine or reflect into
the pilot’s visual space and be a flight
hazard.
Cause thermal damage to aircraft.
Cause the Searchlight to be stuck in the
Gimbal, making it inoperable in the
Elevation axis.
The elevation motion of the Searchlight is stopped when one edge of the elevation stop comes into
contact with a screw head (or a drive stop pin) that sticks out from the inside of the Gimbal arm. To
make sure that the stop operates properly:
•Its area of contact with the screw head (or stop pin) should be at least half the thickness of
the elevation stop itself.
•The contact also should be positive (solid); there should not be contact with a sloping screw
head or with the beveled edge of the drive pin.
•If the screw heads (or stop pins) are worn or damaged, or if the contact area is not at least
half the thickness of the elevation stop, replace the screw heads (or stop pins). Additional
information is in the Elevation Attachment and Movement section.
Source: Spectrolab, Inc. 93
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
5.20 Searchlight Chassis
The Searchlight chassis includes the structural and electronic components inside the rear part of the
Searchlight housing. It includes the reflector and all of the interior components between the reflector
and the rear cover (Figure 43). These components include starting circuits, fan mechanisms, and
focus mechanism. It is important to inspect some of the chassis components, and if they do not meet
visual inspection standards, they should be replaced or repaired before returning the Searchlight to
service. If no repair procedure is mentioned, there is no approved repair procedure. Conduct a
detailed inspection of the chassis (removed from the aircraft) every 24 months or 1,200 flight hours or
500 operation hours.
Figure 43 Searchlight Chassis Showing Internal Components
Source: Spectrolab, Inc. 94
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
5.21 Detailed Inspection with Chassis Removed
DANGER!
The arc lamp contains pressurized xenon gas at approximately
85 to 90 psi at room temperature and up to 370 psi at full
operating temperature.
If the lamp is mishandled, it may explode and send hot, sharp
shards of quartz at high-speed in every direction. These shards
can cause serious bodily injury.
To reduce the risk of serious injury:
Remove power from the Searchlight so it cannot be
turned on during maintenance with front glass
removed.
Only trained personnel should remove window
assembly.
Wear full protective gear that includes safety glasses
or full face mask, long-sleeve jacket, and sturdy
gloves.
If Searchlight has been operating recently, let it cool to
room temperature before exposing lamp.
Never leave exposed xenon lamp unattended.
•Remove the Searchlight from the aircraft.
•Remove the rear cover.
•Disconnect all harness connectors.
•Remove the front window assembly.
•Remove the lamp.
•To remove the chassis from the housing:
oPlace the Searchlight housing in a horizontal position on top of the workbench.
oRemove the 8 Phillips pan-head screws that attach the chassis to the perimeter of
the housing. These screws are located in four pairs around the outside of the housing
(in the midsection of the housing cylinder). Four are attached to the starter board,
and four are attached to the starter plate. All of them screw into vibration proof
locking nut plates. Consequently, there will be resistance to turning them. To avoid
stripping the screw heads, make sure to press the screwdriver into the screw heads
firmly and evenly.
oWhen the 8 screws have been removed, slide the chassis out through the rear of the
housing.
Source: Spectrolab, Inc. 95
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SX-16 Nightsun®Searchlight System
Maintenance Manual
Document 031734-1/Revision A 031734-1 Revision B
January 27, 2014
5.21.1 Ground Wire Inspection
The insulated ground wire is connected to the outer end of the lower left front spider leg (Figure 44).
•Examine the connection point between the insulated ground wire and spider leg for signs of
overheating, corrosion, and broken conductors.
•Examine the general condition of the wire’s insulation and crimp lugs. If you find any defects,
replace the cable.
Figure 44 Front Spider
5.21.2 Front Spider Inspection
Examine the following parts, which are located at the center of the front spider (Figure 44):
•Examine the three lamp centering adjustment screws. These Hex screws radiate from the
hexagonal hub in the center of the spider.
oThey must be straight, free of rust, and lightly lubricated with a high temperature anti-
seize compound.
oThe lamp centering adjustment screws are screwed into the #6-32 self-locking
Keensert® inserts. These inserts should be tight and firmly installed. (located around
the circumference of the light shield). If the inserts are loose, they should be
replaced, but this requires a special Keensert®insertion tool.
•Examine the un-insulated 6 AWG stranded wire that is brazed into the spider’s center ring.
oThis flexible wire provides a complete electrical connection to the front of the lamp.
This connection is necessary because the three radial lamp centering screws do not
form a reliable high-current carrying connection when they are loosened during the
adjustment process.
oIf more than four of the 19 strands of conducting wire are broken, the entire spider
assembly must be replaced.
•Examine the brazed joints located at each end of the spider legs:
oMake sure that the joints exhibit integrity and are free of corrosion.
oIf the silver plating is tarnished lightly, you can remove the tarnish using a non-
abrasive metal polish. Do not use abrasive cleanser, sandpaper, or steel wool to
remove tarnish; this will remove the protective coating, and the parts will corrode and
tarnish even more rapidly.
oApply thread lubricant to each of the three inserts where the spider mounts to the
housing to prevent seizing.
Source: Spectrolab, Inc. 96
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•Examine the light shield to verify the inside is coated with black paint. Also, verify a 1-inch
area the lamp makes contact with is free of paint.
5.21.3 Starter Board Inspection
The starter board assembly (Figure 45) serves as the mounting location for the electrical components
that start the lamp, and it also serves as a structural support for the other interior components. It must
be removed from the Searchlight housing to conduct a complete inspection. Be cautious of the high-
voltage Capacitors (Figure 47) before inspecting the starter board assembly.
Note that the bottom edge of the figure is toward the front of the Searchlight.
•The high-voltage starting components are arranged so that there are large spaces between them
and between any electrical ground locations (including the housing). This prevents uncontrolled
and unwanted arcing. Operating voltages for these components can be as high as 50,000 volts.
•A printed circuit board is attached to the starter board assembly. It contains the lower voltage
components (28 volts DC to about 200 volts DC). These components include the circuits for build
up voltage and voltage sensing.
Figure 45 Starter Board Assembly (Side View)
Examine the starter board for the following characteristics, and make repairs or replacements as
required:
•Examine the molded plastic starter board for overall cleanliness. An accumulation of dirt,
dust, oil, or salt spray mist residue can lead to arcing between high-voltage components.
Source: Spectrolab, Inc. 97
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Look for evidence of arcing, which appears in the form of carbon tracks. Once arcing has
taken place, the components usually must be replaced to eliminate the carbon tracks.
Routine cleaning can be conducted with oil-free compressed air and/or alcohol.
•Examine the starter board for heat and mechanical damage in the central area, where the
nickel plated lamp receptacle (the anode adapter) is bolted in place. If the board is cracked or
charred from overheating, replace the board.
•Examine the printed circuit (PC) board for traces of burning, corrosion, solder joint cracks,
broken component leads, and overheated or otherwise damaged components.
5.21.4 Reflector Rod and Bushing Inspection
NOTICE
Only handle the reflector from the back side. The reflective coating is very
delicate and can be damaged by contact with skin oils or gloves that are even
slightly abrasive. If you touch the front of the reflector by mistake, clean it after
completing the mechanical installation.
The reflector is a delicate, precision optical element that can be easily destroyed
by rough handling. Treat it as if it were thin glass. This will prevent any
accidental distortion, which can cause low candlepower, odd beam shape, and
inability to focus properly.
•Three ¼” diameter (6.35mm) aluminum rods, called reflector support rods or reflector rods,
support and position the 10” diameter reflector (Figure 46). These rods run along the length
of the inside of the Searchlight behind the reflector (Figure 43).
•Each aluminum reflector rod passes through two Teflon® support bushings (Figure 45) and
springs. One of these bushings is located in the aluminum starter plate, and the other is
located in the starter board.
•Three springs the rods provide pressure between the cam follower and the focus cam on the
back cover.
•As the focus cam on the rear cover forces the cam follower (mounted to the rear spider) to
move forward and backward, these rods similarly move back and forth through the bushings
by approximately 3/16” (5 mm). This back-and-forth movement causes the reflector to move
in synchronization with the cam.
Figure 46 Reflector with Rods
Examine all three of the reflector rods and all six bushings:
Source: Spectrolab, Inc. 98
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•The holes in the bushings should maintain a close fit with the reflector rods, but there should
be little friction. If the holes in the bushings become enlarged, the reflector will vibrate or shift
off-center. This will decrease peak beam candlepower and Searchlight utility. Consequently,
the amount of clearance (or play) between the rods and bushings should not be more than
0.010” (0.25 mm). If clearance exceeds 0.010”, the bushings or the rods must be replaced.
•There should be a light coating of Molycote®44 grease on the rods, but they should remain
free of dirt. If there is inadequate lubrication or if dirt adheres to the lubricant, it is necessary
to clean and re-lubricate the rods.
•To clean the rods, wipe them with a solvent dampened rag. Remove all remaining grease
and dirt, and remove all of the solvent until the rods are clean and dry.
•Re-lubricate the rods with a thin layer of Molycote®44. It may be applied with a cotton-tipped
applicator.
•Examine the cotter pins that hold the rods to the reflector support ring. Make sure that the
cotter pins are in sound condition and that the holes in the rods and in the collector support
ring are not oversize.
•Clearance between the cotter pins and insertion holes should be less than 0.005”. A
clearance of 0.010” is the maximum permissible amount.
•If the clearance is greater than 0.010”, replace the rods or cotter pins (or both).
5.21.5 Connector, Pin, and Soldering Inspection
Examine the circular 5-pin power connector (Figure 47). It is shown hanging off the side of the starter
board in the 8 o’clock position. Inspect it for overall condition, cracks in the housing, stripped or
damaged threads, corrosion on the pins, and the integrity of solder joints. If the connector is not in
good to excellent condition, replace it.
You can remove light corrosion from the pins with a non-abrasive electrical contact cleaner.
Apply a very thin coating of light grease (Molycote®44, for example) on the threads to prevent galling.
Figure 47 Starter Board Assembly (Back)
Source: Spectrolab, Inc. 99
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5.21.5.1 T1 Transformer Mounting Feet Inspection
The T1 (combined) transformer has mounting feet consisting of formed sheet metal (Figure 45). If
these feet crack from vibration fatigue, the transformer core and windings can come loose inside the
housing and cause substantial internal damage to the Searchlight.
Examine the mounting feet of the transformer for cracks. If there are any cracks, replace the
transformer.
To isolate the transformer from vibration and to provide additional support, spread a layer of RTV
adhesive under the center portion of the transformer before bolting it into place.
5.21.5.2 Right-angle Floating Nut Plate Inspection
Examine the eight right-angle floating nut plates that accept the Phillips pan-head screws to attach
the chassis to the housing (Figure 45 and Figure 47). Four are attached to the starter board and four
to the starter plate.
•Examine the nut plate rivets for a firm attachment, and make sure that the nut plates are in
good condition.
•If the nut plates are not in good condition, replace them.
5.21.5.3 Arc Lamp Inspection
Inspect the Lamp.
5.21.5.4 Heavy Gauge Wiring and Crimp Inspection
There are four heavy gauge (6 AWG or 8 AWG) high-current carrying wires inside the Searchlight.
These wires make the following connections, and they must be inspected annually.
•One wire connects Pin A on the power connector to the igniter transformer T2 (Figure 45).
•One wire connects the igniter transformer T2 to the anode plate lamp receptacle (Figure 45
and Figure 47).
•One wire connects Pin C to the E1 ground stud on the starter board (Figure 48).
•One wire is the ground wire that connects the starter board E1 ground stud to the front
spider.
Figure 48 Start Board Assembly Showing Components
On each of these four wires, inspect the following aspects:
Source: Spectrolab, Inc. 100
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•Each wire has one or two crimped-on ring lugs. Examine these lugs and crimps for tightness,
freedom from corrosion, and signs of heating generated by a bad connection. Repair or
replace any poor crimps and lugs.
•Examine the solder connections at the connector for corrosion and broken wire strands. If
more than a few strands of the wire are broken, repair or replace the wire.
•Examine the insulation on each wire. If the insulation is worn, damaged, or missing, replace
the wire.
5.21.5.5 Additional Detailed Inspection Items
Make sure to repair or replace any of the following items on the Searchlight chassis if the following
are observed:
•Components that exhibit carbon tracks or traces, which are caused by high-voltage arcing.
•Chaffed wiring and burned insulation.
•Broken insulators/standoffs that support the outer edges of the front spider.
•The two high strength permanent magnets, which are located just behind the reflector on the
metal starter plate (they help the lamp to start and create a more stable arc):
•Use a piece of steel to verify that the magnets still retain their magnetism; high temperatures
can cause demagnetization.
•Make sure that the adhesive that bonds the magnets to the metal starter plate is sound; if it is
not sound, re-bond the magnets with RTV silicone adhesive (such as Dow Corning 732 or GE
108, any color).
5.21.5.6 Reassemble the Chassis
When the inspection is complete, reassemble the various parts of the chassis:
•Slide the chassis back into the housing and reinstall the eight Phillips pan-head screws that
attach it to the housing.
•Replace the lamp (either the original or a replacement lamp if necessary).
•Replace the front window assembly.
•Replace the rear cover.
•Reinstall the Searchlight on the aircraft.
5.22 Routine Inspection Without Chassis Removal
The Searchlight is designed so that the following routine maintenance items can be performed on the
chassis without removing it from the Searchlight housing: anode adapter plate sockets and cable
connection; removal of the reflector; inspection of the bushings, rods, and focus cam; and installation
of a new reflector.
5.22.1 Anode Adapter Plate Holes
Located in the center of the starter board is a nickel-plated anode adapter plate (Figure 47). The
anode adapter plate has three through holes into which the lamp’s three contact pins are inserted. It
is important to have good electrical contact between the lamp’s contact pins and the holes in the
anode adapter plate. In a salty air environment or industrial area, however, the inside of the anode
plate holes can become tarnished or corroded. This compromises electrical contact, and it can cause
problems such as low brightness, difficult starting of the lamp, or cause the lamp to go out when
subjected to vibration (shaking out) or even during a level flight with minimal vibration.
To examine and clean the anode adapter plate holes:
•Remove the front window and lamp.
•From the front of the Searchlight, shine a bright light through the center of the reflector and
down the fiberglass air tube in the center of the chassis assembly to illuminate the anode
adapter plate holes.
•Examine the adapter plate holes. They should be bright and shiny.
•If they are tarnished, remove the rear cover and clean the holes from the rear of the
Searchlight using steel wool, fine sandpaper, or emery cloth.
Source: Spectrolab, Inc. 101
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•If the sockets are tarnished, they can be cleaned with an oil-free solvent such as alcohol. This
also can be used to remove any residue left behind from cleaning the sockets with sandpaper
or steel wool.
•At this time, inspect the pins on the lamp. They are made of copper, and they should be
cleaned to a bright shine. Use fine steel wool, sandpaper, or emery cloth to clean the lamp’s
pins.
•Make sure that the bolted connection to the heavy gauge wire that connects the igniter
transformer T2 to the anode adapter plate is sound and tight.
•Replace the lamp and front window.
5.22.2 Reflector Removal
After time depending on environment, the Searchlight reflector will begin to tarnish and corrode, and
cleaning will no longer restore its reflective properties. If the cleaning procedures were performed
without success, and the reflector exhibits a performance loss, replacement is recommended.
•Remove the front window assembly.
•Remove the xenon arc lamp.
•Remove the rear cover.
•Place the Searchlight face down on a clean, padded workbench surface.
•Loosen the three Phillips pan-head screws that attach the rear spider to the reflector support
rods, leaving the support rods attached to the reflector. The rear spider is spring-loaded, and
the screws must be removed carefully to prevent the springs and washers from flying out of
the Searchlight during disassembly.
•Gently press down on the rear spider as you remove the screws.
•When the screws have been removed, slowly release pressure from the rear spider. After it
moves about ½” to 1”, all tension will be released from the springs.
•Remove the rear spider, and then remove the springs and washers.
•The reflector and rod assembly may slide out of the front of the Searchlight (and onto the
table) at this time.
•If the reflector and rod assembly do not slide out, lift the Searchlight straight up. Gently apply
a small amount of force to the reflector rods; the reflector assembly should slide out the front
of the Searchlight and onto the table as you lift the Searchlight.
•Remove any loose dust from the inside of the Searchlight at this time.
5.22.3 Replacement of Bushings, Reflector Rods, and Focus Cam
Examine the six Teflon reflector rod bushings. Replace them if needed:
•To remove the bushings, remove the e-clip snap ring that holds them in place, and push them
out.
•As you reinstall new bushings, make sure that they float freely in their oversize holes after
installation. This prevents binding and ensures free motion of the reflector and the reflector
rods.
Examine the three reflector support rods (or reflector rods) for wear and to identify their type (whether
they are the old or the current configuration).
•Their nominal outside diameter (OD) should be ¼”. If they do not have more than 0.003” of
wear (in diameter), they can be reused. It is recommended to replace the rods at the same
time the reflector is replaced.
•There are two types of reflector rods, the old configuration and the new configuration:
oIf the rods are cross drilled and have a Roll Pin that is ¾” long and 1/16” in diameter
inserted about 2” from where they attach to the reflector ring, they are the old,
obsolete type, and they must be replaced. On the old type of rod, the Roll Pins acted
as mechanical stops to halt the rearward motion of the reflector.
oIf the rods are not cross drilled, they are the new type (P/N 017000-13). For this type
of rod, the focus cam is used exclusively to stop the rearward motion of the reflector.
Source: Spectrolab, Inc. 102
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•The operation of the reflector differed between the old and new rod configuration (and cam
configuration).
oThe old mechanism (in conjunction with the old focus cam) enabled the reflector to
move only during half of the focus cam’s rotation. There was a dwell period (a delay
in focusing changes) at the widest focus that lasted approximately 5 seconds. At the
end of the dwell period, when the reflector began to move again, the beam then
changed from wide to narrow focus and back to wide focus in only 5 seconds, which
was considered too rapid.
oThe new mechanism enables the reflector to move more slowly and continuously
through its focusing range (no dwell period). It moves through all 360° of the focus
cam’s rotation. This also produces a slightly larger beam diameter and a slower rate
of change in the size of the beam. As a result, the operator has better control of the
beam diameter, which prevents overshooting the correct focus. With the old
configuration, there was less control because the focus motor would coast slightly
after the focus control switch was released.
•If the Searchlight has the old cam, this is the time to replace it with the current part. If the cam
does not have the part number visible, the type of cam can be identified by looking at the
wear marks on the cam:
oOn all of the new cams (P/N 017013-13), the wear marks appear along the entire
outer edge (the entire perimeter). As a result, the gold or silver colored plating wears
off around the entire cam perimeter.
oOn the old cams, the plating will be worn off only on approximately one half (180°) of
the cam’s perimeter.
•If it is decided to re-use the old rods, however, remove them from the old reflector assembly
by straightening them and removing the cotter pins. Then, install them on the new reflector’s
mounting ring. Use new cotter pins when you install the rods.
5.22.4 Installing a New Reflector
NOTICE
•Only handle the reflector from the back side. The reflective coating is
very delicate and can be damaged by contact with skin oils or gloves
that are even slightly abrasive. If the front of the reflector is touched by
mistake, clean it as described properly
after completing the
mechanical installation.
•The reflector is a delicate, precision optical element that can be easily
destroyed by rough handling. Treat it as if it were thin glass. This will
prevent any accidental distortion, which can cause low candlepower,
odd beam shape, and inability to focus properly.
To install a new reflector:
•Lubricate the rods with a light coating of Molycote®44 medium-viscosity, high temperature
grease.
•Clean all grease off of your hands. If you used gloves to grease the rods, put on a new, clean
pair of gloves.
•Turn the Searchlight on its side.
oInstall the reflector’s return springs over the rods.
oReinstall the rear spider so that the cam follower contact surface is to the rear. No
further orientation of the rear spider is necessary. Tighten the screws fully.
•Return the Searchlight to the vertical position with the front of the housing resting on the
table. Test the movement of the reflector:
Source: Spectrolab, Inc. 103
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