S T A R T I N G A N D T E S T I N G
Starting Film Amplifier Equipment
If the film pick-up apparatus is to be used, prepare it for operating, as will now be directed, before starting up the main amplifiers.
It is EXTREMELY IMPORTANT to have the exciting lamp on the film pick-up attachment properly adjusted, with the current at the proper value, as will be specified. The object is to obtain a bright, clear illumination on the photoelectric cell. If the light is not properly adjusted, the volume heard from the horns may be too low or the quality may be poor. As the vibration of the projector tends to jar the lamp and cause it to change its position, go over this adjustment EVERY DAY.
Dust on the lamp and lenses, dirt clogging the openings in the aperture plate and tension pad, or dirt on the film, will also cause insufficient illumination. The film must therefore be kept in first-class condition, and the other parts mentioned must be cleaned EVERY DAY.
After cleaning as just mentioned, proceed as follows:
(1) Close film pick-up switch, mounted on front wall of projection room.
(2) Put lamp in socket and light it by turning control on door of compartment. Adjust control so that meter reads 3.6 amperes.
(3) Loosen lamp socket clamping screw and turn lamp till filament is perpendicular to axis of lens tube. Then, keeping this adjustment, move lamp up or down until filament image is centered vertically on slit in lens tube as observed through window inside of tube. Tighten clamping screw.
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Starting Film Amplifier Equipment
(4) Loosen screw which clamps lamp socket holder and regulate distance of lamp from lens tube by moving socket holder endwise until sharpest possible focus is obtained on slit. This will also give brightest illumination on slit. Tighten clamping screw.
(5) Make sideways adjustment of lamp by releasing side adjustment clamping screw and turning side adjustment knob until filament image is centered horizontally on slit. In making this adjustment, when trying to move bracket, away from you it is necessary to press steadily on the knob at the same time that you turn it; otherwise the bracket will not move. After adjusting, tighten clamping screw.
If making one of these adjustments upsets a previous adjustment, go back and make latter over again. When all adjustments are correctly made, filament image will be bright and sharp and perfectly centered on slit.
Turn control on film amplifier until meter pointer is at the middle of the red mark.
IMPORTANT
After an exciting lamp has been used considerably, the filament may show a tendency to sag. This has a bad effect on the volume, as the filament image no longer coincides with the slit. Another result of ageing that tends to cut down the volume is blackening of the lamp bulb, which reduces the amount of light emitted. Therefore, as soon as the filament begins to sag noticeably or the glass begins to darken, replace the lamp.
On account of the number of operations involved in adjusting the exciting lamp, and the possibility that one may have to be replaced during a show, it is very necessary to have some means of putting in a new lamp and operating it at a moment's notice. This can be done by setting up in the attachment each spare lamp and bracket supplied, and making all bracket adjustments needed for proper operation. As already explained, the bracket can be slipped bodily off the supporting pins, without disturbing any adjustments; the spare lamp and bracket, can therefore be removed and stored away ready for immediate use. If possible, keep the lamp in the bracket; otherwise, mark each so as to permit identification.
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S T A R T I N G A N D T E S T I N G
Starting Main Amplifier Equipment
When the 41-A, 42-A, or 43-A amplifiers are installed, proceed as follows:
(1) See that starting switches on 42-A and 43-A Amplifiers are turned off and that horn safety switch is off.
If starting up during a show make sure that theatre horns are turned off by means of output control key on output control panel.
(2) See that storage batteries are switched on ready for use as covered in preceding section. See that power safety switch is closed.
(3) On 42-A and 43-A amplifiers turn starting switch to "Fil".
(4) On 41-A amplifier, see that filament key is on, and adjust filament control, so that pointer of filament meter is at middle of red mark.
(5) On 42-A and 43-A amplifiers turn starting switch to "Plate".
(6) On 41-A amplifier, press in turn the three buttons marked "Plate Current". Meter marked "Plate" should read in each case not less than 1.35 nor more than 1.55 milliamperes.
(7) On 42-A and 43-A amplifiers, each meter pointer should be on red mark.
(8) Turn on horn safety switch.
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Starting Main Amplifier Equipment
When the amplifier installed is the 46-A, proceed as follows:
(1) See that horn safety switch is off.
If starting up during a show, make sure that theatre horns are turned off.
(2) See that storage batteries are switched on ready for use, as covered in preceding section. Gee that power safety switch is closed.
(3) On DC supply, start motor generator by turning on motor generator switch. On 46-A Amplifier, turn on starting switch, and adjust filament control so that meter pointer is at middle of red mark.
(4) Turn on horn safety switch.
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S T A R T I N G A N D T E S T I N G
Testing Amplifier Equipment
Having started up the amplifier equipment as already described, test it as follows before every show in which it will be used:
(1) If both disc and film equipment is installed, switch in whichever is to be tested first, by means of the film-disc switching arrangement.
(2) Put pick-up equipment on one machine or turntable in circuit, by setting fader at point 9 on side to which this equipment is connected.
(3) If testing disc pick-up, rub needle of reproducer lightly with finger. This should be clearly heard in monitor horn.
(4) If testing film pick-up, see that lamp current is at value previously specified, and readjust if necessary.
Take out light gate by loosening lever setscrew which clamps it. Hold a card or small piece of white paper up against opening which goes to photoelectric cell. An oval spot of light will be seen on it. The edges of this spot will necessarily be soft and blurred but otherwise light should be clear and uniform. If there seems to be a shadow at one end of spot of light, or at top or bottom, give lamp further adjustment, sideways or vertically as the case may be, until shadows disappear. Do not change focus, which has already been set.
Now move card up and down across light spot. Every time this is done a click should be heard in the monitor horn. Finally, replace light gate.
(5) Move fader to other side and test that pick-up equipment in the same way.
(6) Bring fader to zero.
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Shutting Down Amplifier Equipment.
With 41-A, 42-A, or 43-A amplifiers, proceed as follows, and always in the order given here:
(1) Turn off horn safety switch.
(2) Turn off starting switches on 42-A and 43-A amplifiers.
(3) Turn off power safety switch.
On DC supply, also shut down motor-generator set; by turning off motor switch.
(4) Turn off film pick-up switch on front wall of projection room (if installation is equipped for film reproduction).
(5) Turn off storage batteries at battery panel.
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Shutting Down Amplifier Equipment
With 46-A amplifier, proceed as follows,
and always in the order given here:
(1) Turn off horn safety switch.
(2) Turn off starting switch on 46-A amplifier.
(3) On DC supply, turn off motor generator switch.
(4) Turn off film pick-up switch on front. wall of projection room (if installation is equipped for film reproduction).
(5) Turn off storage batteries at battery panel.
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S T A R T I N G A N D T E S T I N G
Synchronous Pick-up Mechanism
EVERY DAY before the house opens test the theatre horns individually and at the same time attend to the lubrication of the projector and pick-up mechanism, and check its operation, as will be described in this section.
Keep a stock of two or three records or sound films especially for testing, independently of those used in the show. Piano, violin or orchestra selections are the most suitable. At least two copies of each record or two prints of each film are required. After starting and testing the amplifier equipment, as previously described, start and test the mechanism and horns by proceeding as follows:
(1) Turn off all theatre horns and if individual dial switches are provided for each horn set these control at zero, that is, turned all the way to the right. Keep on monitor horn with control at usual setting.
(2) On fader, set pointer at zero.
If installation includes both film and disc reproduction, see that film-disc switching arrangements set for type of pick-up which is to be tested.
(3) On each of the two machines which are to be used, oil universal joints on shaft connecting upper and lower gear boxes of projector drive. With film pick-up, or combined disc and film, oil following spots which are all on the attachment mechanism:
Oil hole in hub at inner side of fibre driving gear. On some designs this oil hole is replaced by an oil cup on the end of the main horizontal shaft.
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Synchronous Pick-up Mechanism
Oil cup behind fibre driving gear at right. Oil cup behind fibre driving gear at left.
Oil cup on spindle of tension pulley for take-up drive.
Guide roller above attachment sprocket. Separate the two halves of roller by springing them apart with fingers, in order to get oil to center of spindle. Sprocket pad roller on arm. Idler roller below sprocket.
With disc pick-up alone, oil as follows:
If projector is a Simplex, give grease cup on upper gear box a full turn. If necessary, refill with grease we furnish. Occasionally cheek to see grease channel is clear by turning grease cup till grease is seen coming out beside driving pinion inside projector.
If projector is a Powers, put a few drops of light oil in upper gear box oil cup.
(4) On the two machines, set up two copies of one of test records, or thread two prints of one of test films, exactly as described in next section, "Setting Up".
(5) On each motor control box, see that regulator switch is set at "REG".
(6) Set up operator's and observer's telephone sets. The Manager, or some one else qualified to judge whether reproduction through theatre horns is satisfactory, should now go into theatre and stay within easy reach of observer's telephone.
(7) Start first projector by means of starting switch on motor control box, or line switch for motor control box.
(8) Observe reading of meter on control box. After machine is up to speed, reading should, vary somewhere between 20 and 30 mils, on AC supply, or 50 and 70 mils, on DC supply.
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Synchronous Pick-up Mechanism
(9) See that projector mechanism is running freely and that disc reproducer is tracking properly and has not jumped any grooves, or that film is passing through smoothly.
(10) Bring up fader pointer to one step below correct setting for record or sound film which is being played. Music or speech should now be heard from monitor horn.
(11) If a separate control is provided in the projection room for each theatre horn, turn all these horns on and then off again, one at a time. The observer, who ought to be near the stage, should listen to each horn in turn and check its operation. He should also be sure that the sound from each horn is clear, free of noise, and of full volume.
(12) Put on all horns, with fader at correct setting, and see that reproduction is satisfactory.
(13) If installation includes an emergency system, or an emergency set-up, switch over to each of these arrangements, and. see that reproduction is satisfactory, using all horns. Then switch back to regular arrangement.
(14) Stop first machine by turning off starting switch or line switch. With disc pick-up, put new needle in reproducer and set it back at starting point of record. With film pick-up, rewind film and set it back at starting point.
Now start both machines and compare outputs for volume and quality by switching from one pick-up to other on fader.
With film reproduction, low volume from one pick-up may indicate that the lamp is not adjusted so as to illuminate the film brightly enough, or that there is dirt on the lamp, apertures, or film. If necessary to balance outputs, change lamps or photoelectric cells.
With disc reproduction, change reproducers, if neces-
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Synchronous Pick-Up Mechanism
sary, until two are found that match in volume and quality. (See "Replacements" for method of changing.)
(15) Put fader on zero, stop machines, and put away test records or films.
If the above tests are satisfactory, the equipment is ready for operation.
No lubrication by the projectionist is required for any of our equipment, beyond that specified previously under item 3. The motor-generator used in case of DC supply is also self-lubricating. Our Service Department will give the apparatus any periodic care required in the matter of lubrication beyond what has already been directed. In case any oil gets on one of the commutators by accident, wipe it off as soon as possible and clean out, the slots between the bars with a wooden toothpick to remove any carbon. Treat the projector itself as instructed by the maker.
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