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Music The regular care and proper operation of any piece of fine machinery is the
one way to prevent malfunction and possible damage to its components.
The AQ2A is a fine piece of electronic mechanical equipment. Its precision parts
have been machined to the close tolerances of a fine watch.
Yet, with the kind of ordinary care you will see demonstrated, this projector
should give many years of highly satisfactory service.
Basically, all motion picture projectors operate the same way and require the
same care. But for this demonstration, we shall use motion picture projector
AQ2A1.
When you receive an order or request to screen a certain film, check the
screening room to ascertain what adjustments are necessary for good viewing.
First, the room should be well ventilated. Generally, this room will be a dual
purpose classroom and will need some rearrangement
to adapt it to a screening room.
These windows will have to be blacked out. Any outside light will
cause poor projection quality.
Seats should be placed at an angle for better viewing for everyone.
Position the projector at least six feet from the rear row of seats and make sure
the stand is stable to prevent tipping or rolling
after the projector is in position.
The projection stand must be of such height that the projection light beam is
at least four feet from the floor.
Now, set up the viewing screen.
There are two simple rules to follow when placing this screen. First, place the
screen at least two screen widths in front of the first row of seats.
And second, put the bottom of the screen at least as high as the heads of the
viewers when they are seated.
Now the room is set, the screen is set, so you can start the preoperative
and setup check of the projector.
First, make sure you have a full assortment of replacement parts, including
aperture brush and spare belts, lens tissue, exciter lamp, lubrication oil having
military symbol 2135H, fuses, projection lamp, and a small
bottle of pure grain alcohol.
Now, attach the real arms to the projector in the manner shown. Make sure the arm
with the rewind mechanism goes in the front position.
Keep the pulley wheels toward you and you will have these arms properly
installed. The belts roll easily onto the pulleys. Make sure the
rewind plunger is disengaged.
The rear take-up arm is installed in the same manner.
Before you plug the projector in, check that all switches are turned off. Motor
switches and amplifier controls are located on the back of the projector.
The external loudspeaker receptacle, loudspeaker selector switch, and the AC
power receptacle are located on the front of the projector.
Plug the loudspeaker cable into the receptacle located on the bottom right side
of the projector. Make sure the speaker selector switch is in remote.
Always secure cables and wires to prevent the possibility of someone tripping on
them, causing personal injury and damaging the equipment.
It is a good idea to keep handy an AC power extension to reach the outlet. When
necessary to use one, loop the two ends together before connecting them. This
keeps the strain off the connection.
Before connecting this power cable to the projector, tie it to something solid.
This will prevent a direct pull on the projector in case
someone should trip on the wire.
Make sure the AC line locks into the receptacle on the projector.
Before plugging in the power line, attach the ground wire to the receptacle. This
will eliminate the possibility of dangerous shock.
Now you're ready to test the projector and make the preoperative checks. Flip the
power switch to the on position. This supplies power to both the projector
and to the loudspeaker.
Turn the volume control to the right to about midway in its range, and as the
projector warms up, you should hear a hissing sound coming out of the speaker.
Before going any further, let's see how the audio system works.
This is the sound optical system that synchronizes and
projects the sound with the picture.
The exciter lamp projects the light through this sound lens system. This lens
focuses a beam of light on the soundtrack at the edge of the film.
Should the exciter lamp burn out, turn the locking ring to the right, then turn
the bulb itself to the right and remove.
When replacing the bulb, turn it to the left, thus locking it on the registration
pins. Then turn the locking ring to the left, then replace the housing.
As a further test of the sound system, place a piece of cardboard between the
sound lens and the sound drum. This sound indicates
the system is working properly.
This interrupts the light beam from the sound lens to the photocell.
Place the loudspeaker on a stand near the projection screen. Never put the
speaker on the floor. Loop the cable around the stand leg to take the strain off
the connection on the speaker itself.
With your sound system checked out and set up, you are ready
to check and clean the projector.
Remove the projection lamp cover. Take it all the way off the projector.
Caution, be sure the power to the projector is turned off before
removing any lamps from their sockets.
To remove this lamp, push it down and turn one quarter turn to the left, then
lift it from the registration pins.
This is the projection lamp reflector, and this is the condensing lens. Both of
these must be clean for sharp, brilliant pictures.
Always use lens tissue to clean these using a gentle circular motion.
If there are fingerprints, use a drop or two of alcohol as a cleaner.
When the reflector and condensing lens are clean, replace the projection
lamp with a quarter turn to the right, then wipe this clean too.
Replace the lamp house cover on its hinges and snap it shut.
Now clean the projection lens.
First, loosen the locking screw and carefully remove the lens. Wipe this lens
using a gentle circular motion also.
If there are fingerprints or grease on it, use a drop or two of
pure grain alcohol on the tissue.
When it is clean, replace into housing and set the screw snugly.
Finally, you must clean the aperture plate and the pressure plate.
They are both located here.
Caution, never attempt to remove either of these plates
when the projector is running.
To take these out, first open the film channel by pulling out the release knob
here. Pull the pressure plate handle toward you.
Any accumulation of dust, dirt, and emulsion must come off to avoid scratching or
possible sticking and breaking of the film.
Clean with the aperture brush, never with any metallic object.
If there is gum on it, soften it with a little alcohol on a clean cloth. Then
use the aperture brush again.
Next, take out the aperture plate. Turn the
threading knob to retract the shuttle.
Grasp the aperture plate on top with your left hand. Pull up and lift out.
Remember, these parts come out easily. Never force them.
Here again, all traces of dirt must be removed as you did on the pressure plate.
But to get in corners is a toothpick, stiff card, or a manicurist's orange stick.
Never use anything metallic to clean these plates.
When it is clean, place slots of the aperture plate over the studs on the
mounting bracket, and then, and this is important, push it down all the way.
When replacing the pressure plate, see that the clips top and bottom
engage the mounting brackets.
If this is done right, it slips right in.
And that's about it. You have checked to make sure that you have sound, light,
clean lens, clean aperture, and pressure plates, and all
the replacement parts necessary.
Now you are ready to check the projection light image on the screen. It is
important to check this out before your audience arrives.
Notice the light is high, tilted, and off-center. Center the image by moving the
projector. To lower the image, turn the leveling knob
on the lower front of the projector.
To adjust the tilt, there is a leveling screw on the rear leg of the projector.
Turn it to raise or lower the leg.
Now the projection image is straight on the screen.
You are ready now to put the film on the projector.
But first, make sure the film is the right one, scheduled to be shown, and is on
the reel, heads out. Unroll the film to the title, and hold it up to the light.
You will be able to read the title right side up if the film
has been rewound correctly.
Then put the reel on the feed reel arm. Measure the take-up reel by comparing it
with the feed reel to make sure they are the same size.
If you are short of take-up reels, you can get them in the four sizes from your
film library or order them from the Air Force Film Library Center.
Now you are ready to thread the film.
First, check the path the film will take. There are no
shortcuts to the threading procedure.
The course of the film must follow exactly the route as
outlined on the projector case.
More than 80% of all projector failures during a screening are the direct results
of improper threading of the film.
With about five feet of leader off the feed reel, run the film through the two
film guide rollers at the top of the machine.
Lower the film feed sprocket shoe and place the film under the sprocket, making
sure the perforations engage the sprocket teeth.
Then close the shoe to lock the film in place.
Now turn the threading knob until the words on it read horizontally.
Pull out the pressure release knob to open the film channel.
Thread the film through, leaving a loop the size indicated on the chassis.
Be sure the film is flat against the aperture plate and the teeth are engaged.
Then snap the pressure plate in place.
Turn the threading knob several times to ensure the proper loop.
If the loop does not snap back into position, rethread through the film gate.
Now run the film under the guide roller, leaving a small
loop, then through the sound sprocket.
Check the loop size by pressing and quickly releasing the loop setter button.
This loop ensures proper sound picture synchronization.
Now put the film under the upper idler roller and over the sound drum.
Run the film under the lower idler roller and over the sprocket.
But before engaging the teeth in the sprocket holes, pull the film taut, then
back off about half a frame to engage the sprocket teeth, then close the shoe.
Now thread around the floating idlers on the right, across the bottom, under and
around the lower roller, then to the right of the upper one, and through the top
rollers to the left side of the take-up reel.
Put the end securely on the hub and turn the reel to take up the slack.
More than 90% of all damage to the film occurs in the first 20 feet,
and much of that is the result of improper threading
of the film at the gate area.
The film runs through this gate at 24 frames per second, and as each frame passes
through, there is a slight hesitation of this frame,
as it is flashed on the screen.
To illustrate this action, the shuttle claw moves like a piston, engaging the
film on the downstroke, releasing it at the bottom, and returning
to the top for another frame.
It is during this interval, as the shuttle claw moves from bottom to top, that
the hesitation in film movement occurs, thus accounting
for the stability of the picture.
It's easy to see how a film could be chewed up if not
properly threaded at this point.
Proper threading is equally important here at the sound drum.
To get exact synchronization of sound and picture, there are 26 frames of film
between the picture aperture and the sound lens.
To ensure this exactness when threading, be sure to press and
quickly release the loop setter button.
This sets the lower loop in the film gate area to exact size.
Always remember to screen it right, thread it right.
If any question arises as to the operation of the projector, check technical
order 10D1-2-9-1.
Now it's almost time for your show.
So while the audience arrives, let's recap the main things to do
in preparation for this moment.
Check the room, get it ready.
Check the projector and screen placement.
Check for spares.
Check for power.
Check for sound.
Check that the image is projected properly.
Check the film.
And last, check the film threading.
You know you have done everything right, so you may rest assured
this will be a good show.
Suppose the film broke in the middle of a screening.
Here's what to do to avoid too much annoyance to your audience.
Turn off the projector.
Keep calm and don't let the audience rattle you.
Open the film gate to release the tension on the film.
Flip open the three sprocket shoes and quickly but carefully remove
the film from the sprockets.
Wind the loose film onto the take-up reel.
Lift the broken end of the film and place the new end under it.
Turn the take-up reel to make sure the new end is snug.
Then pull down the film from the feed reel, allowing
yourself a little more than normal.
Then start re-threading.
Remember, this operation must be performed properly, so take your time.
Never attempt to patch or fasten a broken film when a break happens, because you
have already delayed the show long enough.
You can splice the film after the show or send it back to the library after
placing it in the proper can tails out with a note inside the can
stating the film is broken.
Now, suppose you lost a loop during a show.
Without stopping the projector, try to bring the loop back by gently pulling
on the loop with your index finger.
If that doesn't work, adjust the film loop setter knob on the bottom loop.
If that doesn't help at any, push the loop setter button on top of the machine.
You have just completed a film showing, and as in the majority of
screenings, it went along without trouble.
Now, what do you do with the film?
If it goes back to the library, don't rewind it.
Just tape the tail end with masking tape.
Never use adhesive tape as it leaves a sticky residue on the film that could
seriously damage the projector.
Replace the unwound film in the proper can.
However, if you want to show it again, you rewind it immediately.
Pass the end of the film under the rewind reel and
insert it into the slot on the hub.
Give it a turn or two to take up the slack.
Now, engage the rewind plunger by pulling out on it, turning a quarter turn
and letting it snap into place.
Then, flip the rewind switch on the rear of the projector.
Watch the film as it is rewinding to make sure that it goes on the reel properly
and not on the floor if something were to happen.
When the film is rewound, tape the leader with masking tape.
Now, the rewound film is replaced in the proper can for later screening.
Be sure to disengage the rewind plunger.
Follow the procedures outlined in this film and you'll become the best
projectionist in your organization.