Boxoffice (Oct-Dec 1963)

A CONDENSED REVIEW OF NEW IMPROVEMENTS IN SOUND AND PROJECTION EQUIPMENT By WESLEY TROUT T HE PAST TWO years have seen several new improvements in projection and sound equipment. Most modern proj e c t o r mechanisms come equipped with electric changeover built in the mechanism, operated by a foot switch for smooth changeovers. The changeover can be made instantaneous for a perfect change from one to the other projector. It is important to keep the grooves clean that the shutter rides in or the shutter might stick and slow up its action. There is an adjusting screw for speeding up the action of the opening and closing and this should be so adjusted for speed it will close the minute you operate the foot switch. In order to avoid damage to the coil, release the foot switch instantly, do not “ride” it. There have been made many new improvements in 35/70mm projectors recently, too many to go into detail about in our limited space. However, briefly, we will mention a few most important improvements; new, non-glare Plexiglas observation window in mechanism door; new, improved intermittent assembly, quiet in operation, with hardened parts; more simplified, built-in water-cooling circuit; heavier main drive gear set; new spiral gear take-up drive; graphite-impregnated nylon idler and pad rollers; new type threading guards on magnetic shield and idler roller, plus improved lamphouse bracket for easy alignment of lamphouse. For further details, theatre supply dealers or manufacturers of 35/70mm should be consulted, or the technical data presented in our Service Manual. Of course, gears run in sealed housing and lubricant is usually pumped to the main bearings and intermittent movement; many shafts run in sealed-in-forlife lubricated bearings that require no further oiling. Paramount importance is keeping the mechanism (both 35 and 70mm types) clean and free of oil and dirt accumulations. TAKEUP FULLY ENCLOSED The takeup, which rewinds the lower reel, has been improved and the old-type using leather washers has been discarded. The new type is fully enclosed. This eliminates oil getting on the takeup mechanism and assures a smoother operation. The upper and lower magazines have been made larger and easier to handle large reels. In older mechanism, the gears were steel and generally noisy in operation. Now, in the modem mechanism, where steel gears are used, they run in connection with laminated Bakelite gears for unusually silent operation and exceptionally long life. The new gear trains operate very smoothly and have practically no back-lash, even when they have been in operation several years. With gears running in a bath of oil, there is practically no wear and the operation is very quiet. Before we go any further, may we point out that the new 35/70mm mechanism is unit-built? In case of necessity each unit or component can be quickly and easily replaced in its correct position by the projectionist with very few tools to do so. Now, in some of the more modem projectors the units are locked in place by Allen screws, no special tools necessary. In most mechanisms the intermittent movement unit can easily be removed and replaced, and the intermittent sprocket can be turned around and used longer, provided the sprocket teeth are not too badly worn. No taper pins are used, only one set screw. NO SPECIAL TOOLS NEEDED The modem mechanism is equipped with a film gate that is easy to remove and has adjustment for tension on shoes for old and new film. The projectionist can thus remove, for cleaning and subsequently replace, gate shoes, lateral guide rollers, gears, sprockets and gate assemblies quickly, and without having to purchase special tools. The curved gate brought out by several manufacturers is an important improvement in projection. The curved gate has many noteworthy features; among them is better picture definition, sharper focus with buckled film, and the ability to hold the film within the focal plane of the projection lens. This is more important when projecting 70mm film. An important advancement in sound equipment was the RCA replaceable magnetic (cluster) pickup head. One can understand that when the film is running, small particles of the coating, a fine ferrous oxide which is the sound track coating for magnetic sound reproduction, adhere to the pole pieces and act like an abrasive and cause wear after many thousands of feet of film are run over the head. It is now possible to easily replace these heads when they start giving poor sound quality and is not too expensive. THE TRANSISTOR SOUND SYSTEM Next came the transistor sound system that requires less power consumption but plenty of power for high quality sound reproduction. The units are small and with proper care will give years of service with practically trouble-free operation. New circuits have been designed for transistor systems, of course, and the sound reproduction for optical and magnetic is exceptionally fine. Too, considerable improvement has been made in the reproducer and it operates day-in-and-day-out with practically no servicing. Of course, transistor sound systems do require, as with vacuum tube systems, occasional checking and testing to keep them in tiptop running condition. This is discussed in our Service Manual in detail as our space is too limited in this department. However, we will tell you more about transistor equipment in future issues of Modern Theatre. In keeping with the advance of modem technology, The Strong Electric Corp. has utilized the silicon rectifier and grainoriented, tape-wound cores in the design and development of the newly developed Bi-Powr series silicon power supplies. The new Strong rectifier is built to handle two arcs in place of having to use one rectifier for each lamp. It has a single fan and fan motor, a removable, drip-proof cover top, two three-phase silicon rectifiers, a single The neat and clean wiring installation in the projection room of the Queensway Drive-In Theatre, Ottawa, Canada, is noteworthy, as well as the equipment layout. The Queensway was the second all -electric drivein to be built in Canada. See pages 50, 51, The Modern Theatre Buyers' Directory and Reference Issue, October 21, 1 963. Wesley Trout 16 The MODERN THEATRE SECTION