TM 5-6115-275-14 NAVFAC P-8-615-14 TO 35C2-3-452-1 g. Adjustment. (1) The  following  components  and  equipment are needed for the adjustment procedures on the voltage regulator. • DC  Voltmeter  +  0.5  percent,  0-100  VDC  (M  1 and M4) • AC Voltmeter + 0.5 percent, 0-150 VAC (M2) • Oscilloscope (M3) • Voltage source 0-150 VAC 60 Hz, Regulation + 0.25 percent, from 0-2 Amps (PS  ) • Resistor 30 ohms, 120 watts (R1) • Resistor 750 ohms + 5 percent 2 watts (R2) • Potentiometer, 500 ohms (R6) (2) Connect voltage regulator, equipment, and components as shown in Figure 7- 16. (3) Set    potentiometer    R6    to    250    ohms (halfway). (4) Turn AC power supply (PS 1) on. Figure 7-12.4.  Voltage Regulator Adjustment Schematic. (5) Slowly increase AC voltage (O to 30 VAC) while  monitoring  DC  voltmeter  (M  1)  and oscilloscope (M3).  DC voltage reading on DC voltmeter (Ml) shall increase proportionally    with    the    increasing    AC voltage  and  the  voltage  wave  form  trace of oscilloscope (M3) shall move toward a positive voltage level. A voltage shall also be indicated on meter DC  voltmeter  (M4).    The  waveform  trace of  oscilloscope  (M3)  swinging  below  the zero   axis   (negative)   during   this   (0-30 VAC)    test    shall    be    indicative    of    an unusable/defective operational amplifier. (6) Increase   AC   voltage   for   a   "maximum reading"    on    meter    (M    1)    (35    VDC minimum)    or    until    oscilloscope    (M3) waveform  is  just  starting  to  come  off  the "maximum level" refer to curve 1 of Figure 7-17. Figure 7-12.5.  Waveforms. (a) If   the   AC   voltmeter   (M2)   indicates   136 VAC or greater, proceed with step (7). (b) If  the   AC   voltmeter   (M2)   indicates   less than 136 VAC, proceed with step (8). (7) Perform the following adjustment procedures: (a) Adjust AC supply (M2) to 136 VAC. (b) Slowly adjust R6 clockwise until oscilloscope   (M3)   waveform   begins   to decrease   from   "maximum   level".      DC voltmeter  (M  I)  reading  shall  go  to  zero when   waveform   passes    through    zero. Refer to curve 2 on Figure 7-17. (c) Adjust AC input voltage AC voltmeter (M2) to   133   VAC.      The   oscilloscope   (M3) waveform  shall  return  to  maximum  level and     DC     voltmeter     (Ml)     shall     read maximum (35 VDC minimum). (8) Perform the following adjustment procedures. (a) Adjust AC  supply (PS1) to adjust (M2) to 133 VAC. Change 8  7-14.5