Boxoffice (Oct-Dec 1963)

A Checklist to Keep Theatre Projection and Sound in Tip-Top Operating Condition The sound lens is a very important unit in your sound equipment because, if it is not focused correctly, there will be a loss of high frequencies and dialog will not be sharp and clear, the music not crisp and sharp. Dirty sound lens surfaces will also mar sound quality and produce low volume. Use a soft, lintless rag or lens tissue for cleaning. Since the pitch or frequency of the reproduced sound depends upon the rate of speed the track passes the beam of light from the sound lens, it will be quite evident that the correct speed of 90 feet per minute must be maintained. Therefore, occasionally the rate of speed should be checked and the motor speed should also Continued on following page PROJECTION Have you cleaned your lenses and reflectors today? Remember, metal-type reflectors require a different cleaning procedure than glass. Have you checked the asbestos leads on your arc lamp to see if they have deteriorated inside of the lamphouse where it is hot near the holders? See if they are springy when bent. If not, remove and cut the asbestos insulation back about three or four inches, cut this off and make a new connection. High resistance will cause extra current consumption and if the wire is badly corroded and burnt, high resistance will set up and make your meter speed up. Lamps using rotating carbons should have careful maintenance and the contacts in which the carbons are rotated should be cleaned every day with a wire brush. An extra set should be kept on hand and ready to install and the ones used can be cleaned and be ready for installation the next day. LAMP MUST "BREATHE" Keep the interior of the lamphouse clean and free of carbon soot and carbon butts. Be sure the vents in the lamphouse are clean so the lamp can “breathe” and keep down the heat inside. Have you checked the reflector mount and holder to see that the reflector fits snugly but not so tightly it will cause glass reflector to crack? Don’t let dirt or carbon stubs collect in back of the reflector. The proper lubrication of the slides and the feed mechanism is of utmost importance. Keep these parts lubricated but do not over-oil or grease as this is worse than no lubrication — it simply collects dust and causes irregular feeding of the carbons. Check those motor brushes and replace with new when they have become worn down where they don’t have enough contact or the spring does not have enough pressure. It is a small motor and does require proper maintenance to avoid burn out or complete stoppage of feeding carbons. Check the connections frequently, too. CHECKING SOUNDHEAD Sprockets, lateral guide rollers, impedance drum, couplings to motor and gears should be checked at least once a month — sprockets for worn teeth, guide rollers for grooves, impedance drum for free running and motor couplings for alignment and screws. Check exciter lamp to see that the filament has not sagged and the bulb is not blackened or has oil on it. Too, the photocell should not be neglected and should be replaced at least every year or two for high quality sound and sufficient volume output. If exciter lamp filament has sagged, it will cause low volume and inferior sound quality. V>ecort*e <V*° 's pen"'5, Whenever a single rep'a plete ^ Ox parts '»'»<* \q^ >ur pr°'e irnenl pa' LaVezzi Machine Works 4635 WEST LAKE ST. • CHICAGO 44, ILL. KNEISLEY has rectifiers for every installation, CARBON and XENON Arcs Silicon Rectifiers 15 thru 180 amps Selenium Rectifiers 30 thru 180 amps for CARBON ARCS, 20 thru 95 amps for XENON ARCS Tube Type Rectifiers 30 thru 80 amps Silicon Conversion Stacks, 3 phase to replace Selenium Silicon Tubes (SIL-TUBES) for Rectifiers and Exciter Lamp Supplies THE KNEISLEY ELECTRIC COMPANY D.C. Silicon Exciter Lamp Supply Automatic Arc Striking Current Minimizers Coconut Oil Heater only, and Combination Heater-Dispenser See your supply dealer or write, Dept. L., P.0. Box 1506 TOLEDO, OHIO 43603 BOXOFFICE :: October 21, 1963 29