International projectionist (Jan-Dec 1940)

answered a trouble call and found the spring broken which holds closed the pad roller of the takeup sprocket. The projectionist was getting along fine on an emergency basis by using a rubber band to hold the roller closed. — C. W. Hiluard, Altec, Newark, N. J. • • • More Popular Mechanics ideas. The toggle on the end of the takeup reel shaft, used to hold the reel on the shaft, had broken off. While awaiting my arrival with replacement parts the projectionist was getting by with little inconvenience by using a paper clip to keep the reel from sliding off the broken shaft. — E. J. Townsend, ATtec, New York. • • • Here's a real case of low voltage: a theatre reported that voltage on the motors was so low that the "Sentry Safetys" dropped. Upon arrival I found that the voltage to all room equipment had dropped to 60 across the 115-volt feeds, and to 160 across the two-phase circuit. Tracing backward from the room showed that the ground return on the grounded bus of the main distribution panel was burned loose from its soldered lug, thus giving an unbalanced line. Proper voltage was temporarily obtained on an emergency basis by using the conduit for the ground return.— Wm. C. Goodwin, Altec, Philadelphia. • • • Last month Altecman G. H. Miller pointed out that an old KS-6684 exciter lamp rheostat could be substituted for a W.E. 708-A control cabinet, in case of failure of the latter, and made an ideal method of controlling the speed of the drive motor in an emergency. However, Mr. Miller cautioned that the exciter lamp rheostat will heat up to a dull red color and therefore must be adequately protected from coming into contact with anything inflammable. Here is a method I used during an emergency call recently which goes Inspector Miller one better. I used an exciter lamp rheostat as he proposed but, to keep it from overheating, I submerged it in water. In this manner the rheostat will serve indefinitely. A better idea is to submerge it in oil. Either water or oil will conduct away the heat from the rheostat and prevent it from burning up. For those who do not recall the details of Mr. Miller's item in last month's issue, the rheostat is connected across the leads from the motor, which normally go to terminals 3 and 4 of the 708-A Control Cabinet. The motor speed is then set at 1200 RPM by adjusting the rheostat.— E. G. Hemenway, Altec, Binghamton, N. Y. • • • A very easy and accessible arrangement for keeping a constant check on 866-A rectifier tubes in the power amplifier of the RCA P.G. 92, and similar models utilizing these rectifiers { especially where they are arranged close to the floor) is to place a standard mirror switch plate having a round opening in the center which just nicely fits over the tube sockets. A little glue on each end will keep them in place. The filaments, as well as the blue glow, are very discernable from a standing position.— A. J. Seeley, Altec, Syracuse, N. Y. • • • If an emergency situation ever requires that you tinker in an amplifier with a soldering iron, use solder sparingly. And after you finish, check every hidden crevice and corner of the amplifier for stray drops of solder. Unless one is very careful when applying solder to a connection or joint, some of it, when hot, will drip off unnoticed and may drop into some vital part causing a ground or short-circuit. Altecman J. B. Catterall, Cincinnati, had a case of intermittent noise last month and found the trouble to be a small piece of solder lodged between the wafers of a tube socket in an AM-1000 amplifier. And the month before, Inspector R. P. Egry, Pittsburgh, had a similar case of crackling noise which was traced to a drop of solder "shorting" four or five turns of a filament rheostat. • • • Some people with twisted minds apparently don't think that deaf people have enough trouble. They delight themselves with pranks to make the lot of the afflicted more difficr'? The other day I answered what I understand to be the fourth trouble call from theatres in the Chicago area reporting that the hard-of-hearing equipment was not operating. Troubles reported were no sound and low volume. Investigation disclosed that the speech output wires of the hearing-aid system were short-circuited. In each case someone had deliberately cut the wires at one of the seat jacks, skinned back the insulation and twisted the two sides of the circuit tightly together forming a direct shortcircuit. — Steve Welsh, Altec, Chicago. • • • On a recent trouble call occasioned by hum in reproduction on one machine (Simplex System), I found the stiffening web of SH-2033 Sound Bracket Assembly, which unit is normally insulated from SH-1000 Iowa Seeks New Code as Check on Many Theatre Fires A State Fire Code which would include separate provisions covering theatre houses will be sought at the 1941 Iowa Legislature, it has been announced by Fire Marshal John Strohm. The marshal pointed out a lack of present statutes covering theatres and cited the fact that at least six theatres have had serious fires so far during 1940 as cause for more drastic laws. Strohm said he was contacting various officials of the theatre groups to work out planned legislation which he will present to the legislature. Under present plans the state code sought will be drafted after the model code prepared by the national fire board. The fire marshal said the action was aimed particularly at the poorly-constructed houses which are found in some of the smaller communities. He stressed that little fault could be found with the more modern theatres. One of the most commonly found fire hazards, he said, was the lack of projection rooms in some of the houses, or flimsily-constructed booths. sound mechanism by the six SN-158 Paraprene Bushing*, made contact with the sound mechanism evidently due to casting defect. Removing sufficient metal to afford clearance, eliminated the trouble. — F. B. Evans, Altec, Atlantic City, N. J. • • • These stories get monotonous, here it has happened again. Recently a Brooklyn theatre's emergency call concerned a W.E. 43A amplifier that was inoperative and was emitting smoke. Upon checking into the amplifier I found that a "water-bug'' had apparently started to walk across the bottom of V-2 socket. In the course of his walk his front end landed on the plate contact while his rear end still was dragging across the socket casting; result: ground and short-circuit. After cleaning away the carcass, the amplifier operated normally. — Shorty SieGEL, Altec, Brooklyn. • • • Recently a trouble call from a theatre reported that neither projector motor would run. The line fuses were reported to be O.K., but the 110-volt circuit was dead. Before I could reach the theatre the projectionist had got the show going by running an extension cord from another power circuit to the fuse boxes on the sides of the Universal Bases. This is a good slunt to remember because situations of this nature are not infrequent in old theatres which are always having 110-volt power circuit troubles. — G. W. Scott, Altec, Chicago. • • • Existing asbestos covered flexible cables to the carbon holders in the Ashcraft Suprex Arc Lamps are liable to breakage at a point about 2" from the holder. It is well to check these often and rewire them with a more flexible type of cable in order to anticipate failure.— C. C. Curran, D.S.E.L., Halifax, via Altec. OPTICS AND WHEELS BOOKLET The story of artificial light, starting with the primitive torch, going on to the flickering kerosene lamp which the automobile first adapted from the horsedrawn carriage and leading up to the sealed-beam headlight, one of the very latest in the many efficient automotive developments, is told in Optics and Wheels, the most recent of a series of research-type booklets published by General Motors. Its pages show how the scientific facts of optics and light have been applied to solve the problem of safer night driving through the development of the sealedbeam headlamp — a cooperative project undertaken jointly by the automobile industry, lamp manufacturers and highway safety groups. Free copies obtainable from Dept. of Public Relations, General Motors Corp., Detroit, Mich. NEW MOTIO. W. VA. DEALER The Charleston Theatre Supply, 506 State St., Charleston, W. Va. has been named as authorized distributor of Monograph projectors and Mirrophonic sound systems in the Cincinnati film territory. N. E. Mehrie, owner, has been a theatre supply dealer for the past 20 years. 34 INTERNATIONAL PROJECTIONIST