3.2.2 Subcarrier Circuits 
Adjust the subcarrier oscillators as described in Section IV, 2.1.1. With the 
motor-generator turned OFF, place the control lever at the ‘450 FORWARD”’ position and 
adjust the CF BAL control on the discriminator in the model for zero current as indicated by 
the meter. 
3.2.3 Error Regulator 
There are three adjustable resistors in the error regulator circuitry. diusoment 
will probably be required only if components are changed. When making these adjustments, 
a 30- to 50-ohm resistive load with a power rating of 3 kilowatts should be connected to the 
output of the motor-generator in place of the propulsion motor. NOTE: The motor-generator 
output should be kept low or at zero except for short periods while making these adjustments. 
1. Set the range switch on the error regulator to the 300-volt position. 
2. Adjust the propulsion control lever for zero output current on the meter of the 
discriminator. 
3. Adjust the ZERO control (R-1, Figure 58) for a motor-generator output of 
150 volts. 
4. Check the output voltage versus control lever position. Zero on the control 
lever should produce zero output and 100 on the lever should produce an output of 300 volts. 
If the range is not correct, adjust the SENS control on the discriminator. 
5. Connect a test set such as a Simpson Model 260 to the BAL TEST terminals on 
the printed circuit board, Figure 57. Set the meter on the 2.5-volt d-c scale and set the pro- 
pulsion control lever for a 150-volt output. Adjust R-3 (on the printed circuit board, Figure 57) 
for zero voltage on the test set. 
6. Connect an oscilloscope across the resistive load. Set the RANGE switch on 
the error regulator for 150-volt output. Introduce a transient into the system by rapidly moving 
the control lever within the central portion of its range. Observe the transient response on 
the oscilloscope. If necessary, adjust R-2 (GAIN) for a damping factor of about 0.4 to 0.6, 
i.e., 10 to 20 percent overshoot. 
7. The emitter current of the output stage may be monitored at the test points on 
the panel. A 5-volt drop across these points represents 1 ampere emitter current, which is 
approximately full drive to the motor-generator. 
3.2.4 Spare ON-OFF Channel 
No adjustments are required except the amplitude of the tone oscillator signal into 
the mixing network. See Section IV, 2.3, for details. 
IV-6 
