itself , If the tape should break during operation, it will probably be 

 kinked so that nothing can be done to repair it» The tape unit must be 

 removed and shipped to USN USL for the installation of a new tape,, If it is. 

 accidentally broken when the unit is not in operation, it may be temporarily 

 repaired by soldering the broken ends together. This is only a temporary 

 measure, however, because the joint will tend to throw the pole pieces away 

 from the tape as the tape passes between them. Since these pole pieces are 

 under spring tension, they may again shear the tape as they spring back into 

 place. Normally, the tape ends are welded and the joint dressed down until 

 smooth., If it is in any way possible to do so 3 the tape unit should be returned 

 to USN USL for repair, 



95 o To prevent rusting, the tape is oiled by an automatic reservoir in 

 which oil is filtered, stored, and distributed constantly while the machine 

 i» operating. This oil supply will require replenishing every two to three 

 months. Do this with the machine inoperative. Remove any dirt or debris 

 which may have collected in the oil pan located directly below the pole pieces 

 and drop 20 to 25 drops of fine grade machine oil (such as sewing machine oil) 

 into the pan. 



Servicing the Amplifier and Recorder 



96, With the exception of occasional tube replacement the amplifier should 

 require little servicing. It is located directly in front of the tape unit 

 with which it is connected by three cables. One cable is the power cable 

 from the motor, terminating in a plug which fits into a socket on the amplifier 

 chassis , The second cable goes from the amplifier to the recording head n 

 the tape unit and may be disengaged at the recording head end. The third 

 cable goes from the amplifier to the terminal strip on the back of the tape 

 unit. Before the tape unit or the amplifier can be removed, these cables 

 must be disconnected, 



97c The tape unit can be removed from the rear of the rack by removing the 

 five screws which bolt it to the tray. These are located below the tray 

 at the four corners and rear center of the tape unit. The amplifier unit 

 may be removed from either the front or back by removing the control knobs 

 at the front and the four screws which bolt it to the tray, .These are under 

 the tray at the four corners of the amplifier,, When the amplifier is ^removed 

 from the front it is necessary to remove the front panel, The recording-eye 

 indicator tube is connected permanently to the amplifier unit by a cable; 

 when the amplifier is removed this eye indicator tube must be slipped from 

 the bracket which holds it to the panel and the jack receptacle 

 must be unscrewed, 



98, The tape unit motor is connected to a speed reducing pulley by means 

 of a belto The pulley in turn is connected to the main drive pulley by 

 another belt. This drive mechanism is located on the side of the tape unit 

 nearest the amplifier. Tension on the drive belt is adjusted by moving the 

 motor on its sliding base when long use has caused the belt to loosen. 



~ 23 



