c) Apply power to the recorder, and set the "calibrate-signal" 

 switch on the front panel to the "calibrate" position. 



d) Adjust the right adjusting potentiometer on the front panel 

 to provide a reading of 0.8 volts on the right panel meter. 



e) Adjust the left potentiometer on the front panel to provide a 

 swing of 400-0-400 on the left meter. If the meter does not 

 swing equally on each side of zero, adjust the centering 

 control on the recorder chassis to obtain equal movement of 

 the meter pointer on each side of center. Due to the inertia 

 of the meter movement, the meter pointer will not provide an 

 accurate indication of the actual current in the meter. To 

 get the precise peak pointer-movement of the meter, it is 

 necessary to stop the synchro shaft at its peak signal point 

 of rotation. To do this, set the switch on the chassis near 

 the synchro to the "calibrate" position, and grasp the coupling 

 attached to the synchro shaft and turn it manually to provide 

 peak indication on the left panel meter. Adjust the panel 

 control for the proper 400-0-400 movement of the meter corre- 

 sponding to the physical location of the synchro shaft that 

 produces maximum swing of the meter. The centering control 

 may require further adjustment at this time. Adjustment of 

 the oatihration signal -is very important as it is used to 

 standardize the wave gage signal and the spectrum analyzer 



in the CERC laboratory. Return the calibrate switch near the 

 synchro to its "operate" position when the above adjustment 

 is completed. 



f) Connect the signal cable from the magnetic tape recorder and 

 the signal cable from the strip-chart recorder to the calibra- 

 tion unit as shown on Figure 50. 



g) Set the voltage-control potentiometer on the top of the cali- 

 bration unit to its counterclockwise position. 



h) Apply power to the tape recorder and strip-chart recorder, and 

 set the calibrate switch on the front panel to "off". 



i) Adjust the strip-chart recorder pen to the center line on the 

 recording chart using the manual control on the penmotor. 



j) Place the tide-capacitor switch on the tape recorder chassis to 

 the "out" position (switch closed) . 



k) Apply power to the calibrate unit, and adjust the strip-chart 



recorder pen for full-scale indication (one-half of chart width) 

 using the voltage-control potentiometer on the calibration unit. 



1) Adjust the bottom center control on the tape recorder panel to 



98 



