4 years ago



KEEP YOU SI PROJECTORS IN TOP OPERATING CONDITION WITH S^ PARTS Good booth equipment is the most vital item of theatre operation — and by far the least costly. Replace worn parts promptly. Catalog on request LAVEZZI MACHINE WORKS 4635 West Lake Street Advanced — Chicago 44, Illinois DESIGN in Griggs Chairs Solid steel cen* ter give standards strength and durability. PROJECTION AND SOUND Tips on Trouble-Shooting For Men in the Booth by WESLEY TROUT Starting this MONTH, we will present servicing data on both projection and sound each month. We have received many requests from our readers, saying they would like to read about both subjects in each issue of Modern Theatre. We Wesley Trout think it is a good idea, too, so here goes! Let us start with the mechanism first. Keeping the projector mechanism olean Ls one of the best ways of assuring highest quality projection from any make of projector. The interior of the film compartment of most all modern mechanisms is large and roomy; ample space is generally provided between all units to facilitate rapid and thorough cleaning of all parts. The interior of all film compartments is now painted a light color which aids in observing dirt and other foreign matter, thereby making it very easy for the projectionist to keep clean. DAILY CLEANING BEFORE SHOW We cannot too strongly point out that every projectionist should cultivate the habit of cleaning all parts of the mechanism every day before the show starts. A soft, clean rag and a small stiff-hair brush is all that is required to do a first-class cleaning job on any projector mechanism. The sprockets in the projector mechanism and sound head should be brushed around their entire periphery to remove all deposits of dirt and film emulsion: the pad rollers should also be brushed and then wiped with a clean rag; the film strippers should be checked and all the dirt and emulsion deposits removed. Dirty sprockets will cause trouble. Dirty intermittent sprocket will cause picture jump, and dirt on takeup sprockets will cause loss of loop. Dirty sound sprockets will cause poor quality of sound reproduction. Use a stiffbristle tooth brush for cleaning sprockets. WATCH THE FILM TRAP Another very important unit in the film compartment of any make of projector is the film trap and gate assembly. Keep them clean! The film gate should be removed daily and very thoroughly cleaned with a clean rag. Next, the film shoes and guides on the aperture plate should be thoroughly cleaned daily, making very sure that all deposits of dirt and film emulsion are removed. It is of utmost importance care should be taken when cleaning between the film guide rollers and the film trap main casting to remove all dirt and foreign matter which may prevent their turning freely. Remember that failure of inner roller to turn when film is passing through the film trap may result in it becoming cut by the edges of the film. Once a groove is cut in these rollers, it will be nsures years of hard wear in a chair with comfort and beauty. WRITE FOR CATALOG GRIGGS EQUIPIVIE^T CO. Belton, Texas Disconnect one end of resistor or condenser to GOLDE SPOTLIGHT STOPS TRAFFIC! r Long-life GoldE spotlights brighten lobbies, displays, etc. U L Ar^ proved. Easiest to set up, most cnm pact. Instant-lock tilt, heat-proof Iff ncl lens, porcelain socket, asbestos curd, removable cast base. Two models— 500 watts. 1000 watts blower-cooled. Pipe clamps, color wheels, color frames avail able. Sec >our dealer— or write to ^ GOLDE MANUFACTURING CO. Dtpt. BO. 4888 N. Clark St., CHICAGO 40, ILL. To respond to this advertisement. the free postcard This diagram stiows proiectionists how to use an ohmmeter to check defectiye amplifier components. When there is trouble in this mechanism the thing to do is to try to tie the trouble down to some specific unit in the sound reproducing system. In this maKazlne and write In this .id's Ko.v No. :\i; v 36 The MODERN THEATRE SECTION

— This is a block diagram of a typical sound equipment layout. If a projectionist does not have a schematic furnished by the manufacturer, W T o H.P. SPEhKeR, he should make a diagram of his sound equipment units. Fuses should be marked in such a layout so they may be located instantly in cose of on emergency. O I A P.E-.C^i-l. TJ -cff iir L.F. SPe-M^FR difficult to keep them turning, and it will be necessary to replace with new rollers. A drop of oil on the shaft will help keep them operating freely. After cleaning all the individual units in the film compartment, the entire interior of the film compartment should be thoroughly wiped clean with a soft, dry rag. The projectionist should never clean the projector when it is running. Failure to adhere to this advice may result in damage to the mechanism by getting the cleaning rag caught between the gears or tangled between the shutters and shutter housing. Every day the projection lens should be removed and carefully cleaned with lens tissue and cleaning compound. Dirty lenses will cause poor focus and light loss. Care should be used when cleaning the lens so as to prevent scratching, or maybe coating them with thin film of oil or grease. Guard against this by using only clean, soft rag (lintless ragi or lens tissue. We strongly recommend that you use only lens tissue for projection and sound lens cleaning. Thoroughly knowing your sound equipment components is important in order to do quick servicing. Every projectionist should be thoroughly acquainted with all the equipment under his control. He should know the location of every fuse and switch that control power and light circuits in the theatre. A block diagram, like the one presented on this page, should be made of his sound equipment units, or one should be obtained from the manufacturer. A schematic of the amplifier, pre-amplifier and other units is a "must" in any projection room. The scliematic should give the following data: resistor and condenser values, voltages at tube sockets, color codes used, data on power transformer, output transformer, chokes, etc. For quick troubleshooting, this data is absolutely necessary. Most leading manufacturers will gladly furnish this information and schematic, or it is sometimes pasted inside of the lid of the units. Don't make any changes unless you know it will improve your sound, if your somid reproduction is all right. It is best to establish a systematic routine when searching for trouble. Keep cool! When sound is completely dead, first thing to do is to check A.C. power supply. Continued on following page ': i ,c -'-'pi-.- .':' Leading Chains and Drive-ins CHOOSE B&L SUPER CINEPHOR LENSES Bausch & Lomb Super Cinephor Lenses provide the extreme color correction, sharp definition and edge-to-edge brilliance necessary to project the finest possible screen images. That's why theatres nation-wide are replacing old lenses with Super Cinephor Lenses for their showings of great pictures. Build patronage . . . build profits . . . with vivid, sparkling screen images. Replace NOW with B&L Super Cinephor Lenses 44% to 100% brighter! WRITE for complete information to Bausch & Lomb Optical Co., 720-13 St. Paul St., Rochester 2, N. Y. Bausch & Lomb Projection Lenses BOXOFFICE January 3, 1953 37