The motion picture projectionist (Oct 1927-Sept 1928)

14 The Motion Picture Projectionist September, 1928 Replacements forW. E. Equipment By Electrical Research Products Engineering Staff THIS article will cover the principal replacements and repairs required on the equipment. Any worn out or defective part of the equipment must be replaced only by the spare or replacement part furnished or recommended by us for that purpose. Order replacements by the names used in this bulletin ; this will save much time and confusion. The attention of projectionists is directed to the following clauses of our standard contract with theatres : "2. The Exhibitor agrees that it will use and employ the Equipment only in the Theatre, and that it will at all times during the period of this license keep, maintain and operate the Equipment in the manner from time to time prescribed by Products and in no other manner. .... Therefore, in order to secure and insure the functioning of the Equipment to the satisfaction of the parties hereto, the Exhibitor shall not, without the written consent of Products move, alter, change or modify the Equipment, nor add anything thereto nor take anything therefrom ; nor break the seal upon any part or collection of parts which is or may be sealed by Products ; nor operate, use or employ the Equipment in any manner in conjunction with any record of sound or with any other device or combination of devices in any way related to the production or reproduction of sound, unless said records, devices and combinations of devices (other than those made under license from Products for such use) shall have been first tested by Products and found by it to operate properly, reliably and efficiently and to reproduce sound with accuracy of quality and adequacy of volume, and approved by the legal counsel of Products as to freedom from infringement of patents. Also, in order further to secure proper functioning of the equipment as aforesaid satisfactorily to the parties hereto, it is agreed that all additional and renewal parts and assebled parts for said Equipment shall be obtained from Products." General Instructions In accordance with this, while projectionists are expected to follow the instructions previously given for dealing with equipment troubles and to do simple repair work on the apparatus, — such as soldering broken connections, replacing burnt-out tubes or burnt-out fuses, tightening loose parts supplied or recommended for the purpose by us, etc. — it is expressly forbidden to experiment with the equipment by changing circuits or substituting coils, condensers, etc., of other types, or by using records of types not authorized by us, as this might result in a situation constituting default of contract. Tubes that have once been used in a rectifier are unfit for use in amplifiers, as they are incapable of giving good quality. Therefore, be sure to exercise care on this point in handling the stock of spare vacuum tubes. Changing Receivers If a defective receiver is found by application of the various tests described in these instructions, replace it by one of the spares furnished by ERP. Be sure to connect each wire to the same terminal on the new receiver as it was connected to on the old one. All four receiver terminals are marked for this purpose. If a receiver is connected wrongly the quality of the sound as heard in the house will be spoiled. Never open receivers nor attempt to repair them. Never operate a receiver without the horn, as this may damage it. In installations having only one horn, if this horn is provided with a receiver switching device the spare receiver may be put in use by simply moving over the throat lever. The double-throw switch located in the stage cut-out box, which controls the sound circuit to the receivers, must also be thrown to the other position so as to connect in the spare receiver. Changing Reproducers If a defective reproducer is found by application of the various tests described in these instructions, replace it by one of ihe spares we furnish. The base of the reproducer assembly (swivel, arm and reproducer unit) fits on a bracket attached to the turntable pedestal. This base is clamped to the bracket by means of a milled thumbscrew. When this thumbscrew is loosened and the output leads disconnected from the connecting block, the whole reproducer assembly can be removed. The simplicity of this operation makes it the best method of changing reproducers quickly. To change a 4-A reproducer unit, remove the two screws attaching the unit to the arm; you will see one of these screws at each side of the reproducer just behind the head. This leaves the unit loose except for the output leads ; turn it over on its back, thereby exposing the terminal block, and remove the leads by loosening the binding screws that attach them to the terminal block. To put in a new 4-A Unit, follow these operations in reverse order. On no account open a 4-A reproducer unit or loosen any screws other than those mentioned, as it is filled with a special damping compound and will be ruined if this leaks out. Never attempt to repair or adjust reproducers. Before using a new reproducer during a show, test it by playing a record with it and listening across its terminals with the headset. Splicing Sound Film 1. Disc Reproduction. Vitaphone film has 16 frames per foot, and each foot is numbered. Beginning with "0" at the starting mark, the 16th frame after the starting mark is marked No. 1. The 16th frame after No. 1 is marked No. 2, and so on throughout the print. There are, therefore, IS frames without numbers between each pair of numbers. By this system, the position of every single frame in the reel is indicated. In synchronized features there are in addition other numbers on the margin of the film which indicate the scene numbers of the picture. These numbers can be distinguished from the footage numbers, because they have a dash at each side, as for instance " — 286 — ", the footage numbers themselves being simply "286," without the dash at either end. In cases where the scene and footage numbers conflict, the footage number is omitted, but is counted, and reference will have to be made to the next footage number in sequence. If a footage number does not appear at each 16th frame, continue counting until you reach the next number, when you •should then have 31 frames between the two footage numbers. With the numbering system described, it is easy to ascertain whether or not a print has the proper number of frames, by simply examining each splice and counting the footage numbers on each side. The two numbers should be consecutive and there should be 15 frames without numbers between them. In case of a break in a film, make a patch by inserting black leader. Be sure that the number of frames of black leader inserted is exactly the same as the number of frames you take out of the film, plus the frames used for the patches. After putting in the black leader, be sure to check-up and see that the numbers follow in sequence and that there are exactly 'IS frames without numbers between each pair of footage numbers. If any numbered frames are missing, or if the missing portion is more than 1 foot, you will have to check both sides of the break to the next number, and after making the splice, see that you do not forget the intervening frames. The procedure for patching sound film has already been explained in detail in these columns.