Motion Picture Herald (Mar-Apr 1945)

wm LICENSED UNDER U.S.I WESTERN ELECTRIC CO. INCORP PD SIR M P I F I E R TOPS IN QUALITY THROUGHOUT, — THE OUTSTANDING PERFORMANCE RECORD OF THE PD -50" SERIES AMPLIFIER IN HUNDREDS OF THEATRES THROUGHOUT THE WORLD UNDER MOST SEVERE OPERATING CONDITIONS,^ A GENUINE TRIBUTE TO THE DESIGN AND ENGINEERING FEATURES THAT MAKE POSSIBLE CONTINUOUS, UNINTERUPTED LOW MAINTENANCE COST OPERATION ITS (RE THAN AH AMPLIFIERIT'S A MIRACLE OF TROUBLE-FREE OPERATION IE BALLANTYNECO. <AHA,2,NEBRASKA.U.SAj ^jam brdst DENVER. COLO., WIRING SYSTEMS FOR CHANGEOVER SERVICING In servicing projection changeover devices, types are encountered other than the 6point, 3-wire foot switch type commonly installed. Here are diagrams of two other kinds which may prove helpful to many projectionists and others concerned with theatre equipment maintenance. COILS OA/ P/ZOS. / Coit-5 ON P2QJ. 2 TO 4 /4 BEC W/ees /n compu/t BLACK-lV/eF FPOAT AC oe. DC SO PPL y panfl , c/ece//r ro f/Ai/e Co/ is on peo<s. / CO/LS ON PgQJ. £ YeLLow-w/ee 3^14 BRC Mees /N CPF£N F/eio, Foot Sw/rcf/ on PLooe oe on peoj. basf /V fpont LJ •BI30WN no W/BF ' 3 ■Beowti WISE 3J4J30C tv/ees //V g eeew F/&/.& *j* ? Foot sin/ ret/ on fu. oo/e, oe on Peoj. 34se /N FBONF WHire W/ee _ 4 '■ /4££C W/ees w conou/t BLACK IN/ f2F FeoAf AC oe DC JuPPLr PA NFL . C/ Ecu it tv nai/f Fi/se 4 switch FIGURE 2 shows the 4-point, 4-wire changeover system that uses only three points in each switch for a two-projector installation. The yellow wire to the opening coil on the projector is connected to terminal post 2 in each foot switch. The black or positive wire is connected to terminal post 3 in both foot switches. The white or negative wire runs straight through and is connected together to the common return, or center lead, from the changeover coils on the projectors. The brown wire to the closing coils is connected to terminal post 4 inside of each foot switch. It is to be noted that the identifying colors of the wires is taken arbitrarily and can be changed as desired, but the sequence in the wiring installation should be followed as explained above. — J. J. S. FIGURE I shows the wiring connection of a 3-point, 4-wire foot switch changeover for two projectors. The wiring of this particular changeover is as follows: The wire to the opening coil on the projector (a yellow wire) is connected to terminal post I inside the foot switch; the positive wire (black) to terminal post 2, which connects with post 2 on the other foot switch. The wire to the closing coil on the projector (brown) is connected to terminal post 3 inside the foot switches, and the white or negative wire runs straight through and connects the common return, or center lead, from the changeover coils on the projectors. POST-WAR THEATRE SOUND {Continued from page 9) ceptance and popularity is its simplicity, compactness and dependability under adverse battle conditions; these have made it standard in aircraft, battleships, and fire control centers to record all inter-phone conversations and orders during engagements. Wire recording, however, due to its limited frequency response and difficulties in speed regulation, will not be likely to replace our persent film and disc recording methods regardless of the favorable publicity it has received; it will rather open new fields in the recording of speech and in the use of the dictaphone. Television holds the greatest 'promise of any of the electronic "war babies," bringing t the public two new fields of entertainmentone in the home, the other in the theatn Plans are now being made to set up larg television projection receivers and screens i theatres throughout the United States, cot necting these theatres by means of coaxh telephone cables to the major theatrical an film producing centers in this country. England has had successful experience i the field of television and plans to enlarg this development as soon as equipment available. China, being a large nation, rea izes the importance and the value of televisio 16 BETTER THEATRES, APRIL 7, 19