Do not permit the screw to turn as the lock nut is tightened. Make a final test when this is tight. If the damping device does not act in the manner described, notify your service man. Check each damping device twice weekly. The purpose of the lower take-up sprocket is to prevent the flutter that a poor takeup, or a bent take-up reel would introduce by jerking the film engaged on the constant speed drive sprocket.

The contact surface of the felt washer should be kept lubricated with Alemite grease. This is accomplished by keeping the grease cup shown in Figure 63 filled with this grease and giving the cup a half turn once for every three hours the projector is run. Do this while the machine is idle, then start it up and let it "turn over" a few minutes before threading up. Turning the grease cup while the projector is in motion may impart a "wow" for several seconds.

93. Threading the Type PS-1 Sound Head.-The Type PS-1 sound heads are threaded as shown in Figure 60. After leaving the lower take-up sprocket of the projector head and passing into the sound head, the film passes between the sound gate guide rollers and then through the sound gate. The film then passes over the constant speed sprocket. The loop between the lower take-up in the projector head (through the gate) and the constant speed sprocket should be about two sprocket holes. After passing the constant speed sprocket the film passes from the right under the sprocket to the lower take-up sprocket. A loop of four sprocket holes should be left between the constant speed sprocket and the take-up sprocket. The film,, after leaving the constant speed sprocket and passing under the take-up sprocket, goes direct to the lower magazine. After closing the sound gate take out any slack between the sound gate and the constant speed sprocket by drawing the film up through the gate.

94. Adjustment of the Pad Rollers.-The pad rollers on both sound head sprockets should be adjusted in the same manner as the pad rollers on the Simplex heads; that is, set up so that two thicknesses of film will just pass between the sprocket and the roller. Under no condition should the fibre roller of the constant speed sprocket turn when the film is passing through. It should just move when a patch passes through.

7