basically all motion picture projectors operate the same way and require the same care but for this demonstration we show use motion picture a projector a q two a one when you receive in water 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 general a 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 every one 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 p 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 the screen first place the screen at least two screen with in front of the first row of seats and second but the bottom of the screen at least as high as the heads of the viewers when they are seated now the room is that the screen is set so you can start the pre operative and set up check of the projector first make sure you have a full assortment of replacement parts including average or brush and spare belts lens tissue exciter lamp lubrication oil having military assemble twenty one thirty five age fuses projection la 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 the rear take up farm is installed in the same manner before you plug the projector in checked that all switches are turned off motors which is an amplifier controls are located on the back of the projector the external loudspeaker receptacle loudspeakers selector switch and the ac power receptacles are located on the front of the projector plug the loud speaker cable into the receptacle located on the bottom right side of the projector make sure the speakers elector's which 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 recept  on the projector before plugging in the power line attach the ground wire to the receptacle this will eliminate the possibility of dangerous shots now you're ready to test the projector and make the pre operative jacks flip the power switch to the on position this applies towers to both the projector and to the loudspeaker turn the volume control to the right through about midway in its range and as the projector warms up you should hear a hissing sound coming out of the s before going any further let's see how the audio system works this is the sound optical system that synchronizes then project the sound with the picture the exciter lamp projects the light through the sound lens system this lens focuses a beam of light on the soundtrack at the edge of the film showed the exciter lamp burn out down the locking ring to the right then turn the bulb itself to the right and remove one replacing the bulb turn it to the left  locking it on the registration pin 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 lense and the sound drum this sound indicates the system is working properly this interrupts the light beam from the sound lense to the photocell place the loud speaker on a stand near the projection screen never figure on the floor loop the cable around the stand leg to take the strain off the connection on the speaker itself 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 and 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 lifted from the registration then this is the projection lamp reflector and this is the condensing lens both of these must be clean for sharp brilliant fixture it's always used lens to shoot a clean the is using a gentle circular motion if there are fingerprints use a drop or two of alcohol as a cleaner one the reflector and condensing lens are clean replace the projection lamp with a quarter turn to the right then wipe this clean to using a gentle circular motion also if there are fingerprints or grease on it use a drop or two of your grain alcohol on the tissue when it is clean replace into housing and set the screws snugly finally in 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 all the pressure plate handle toward you any accumulation of dust dirt and emotion must come off to avoid scratching or possible sticking and breaking of the film cleaned with the  never with any metallic object if there is gum on it soften it with a little alcohol on a clean cloth then use the but your brush again next take out the aperture plate current 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 that too thick stiff card or a manicurist are inch thick never use anything metallic when it is clean place lots of the aperture plate over the studs on the mounting bracket and then and this is important push it down all the way by replacing the pressure plate see that the clips top and bottom engage the mounting brackets if this is done right it slips a right in and that's about it you have checked to make sure that you have sound light plane lands clean  aperture and pressure plates and all the replacement parts necessary now you're 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 center under the image by moving the projector to lower the image turn the leveling knob on the lower front of the project to adjust the tilt there is a leveling screw on the rear leg of the project harness to raise or lower the leg now all 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 real heads out on roll 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 then put the real on the feed real arm measure the take of real by comparing it with the feed real 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 that are now you are ready to thread the film first check the path the film will take there are no shortcuts to the threading procedure a course of the film must follow exactly the route as outlined on the projector case more than eighty percent of all project are failures during the screening are the direct results of improper threading of the film with about five feet of later off the feed real run the film through the two film guide rollers at the top of the machine lowered the film feed sprocket shoe and place the film under the sprocket making sure of the perforations engage this brocket  then close the chute to lock the film in now turn the threading knob until the words on it read horizontally pull out the pressure release knob to open the film channel read the film through leaving a loop the size indicated on the chassis 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 re thread through the film gate now run the film under the guide roller leaving a small lope then through the sound sprocket check the loop size by pressing and quickly releasing the loop setter button this loop ensures proper sound pictures synchronisation 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 all the film taut then back off about half a frame to engage th 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 real  at the end securely on the hub and turn the real to take up the slack more than ninety percent of all damage to the film occurs in the first twenty feet and much of that is the result of improper threading of the film at the gate area of film runs through this gate at twenty four 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 call 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 call 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 twenty six frames of film the tween the picture aperture and the sound lens to ensure this exactness when reading the short of breath and quickly release the loops that are button this sets the lower lobe in the film gate area to exact size always remember to screen it right read it right if any question arises as to the operation of the projector check the technical order ten the one dash to dash nine dash one 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 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 the 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 real lift the broken end of the film and place the new end under turn the take up real to make sure the new end is no then pull down the film from the feed real allowing yourself a little more than normal then start retreading remember this operation must be performed properly so take your 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 dan tails out with a note inside the can stating the film is broken now supposed to last a loop during a show without stopping the projector dry to bring the loop back by gently pulling on the loop with your index finger if that doesn't work just the film moves that are knob on the bottom loop if that doesn't help th 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 as 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 blunder 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 real properly and not on the floor if something were to ha film is replaced in the proper can for later screening be sure to disengage the rewind blunder follow the procedures outlined in this film and you'll become the best projectionist in your organization