TM5-6115-593-34 NAVFAC P-8-631-34 TO-35C2-3-463-2 brilliance.    If  light  does  not  come  on, adjust R3 on voltage regulator. Normally, R3 is set to provide R1 with an adjustment of ±10 percent of rated range. (7) When     R3     and     R1     are     correctly adjusted,  a  small  change  in  R1  will turn the light bulb on and off.  If light stays   either   "full   on",   or   does   not come  on  at  all,  the  voltage  regulator is defective. NOTE R4  on  voltage  regulator  affects  speed with   which   light   turns   on   and   off. Normally    it    is    factory    set    in    the extreme clockwise position. This setting normally assures good stability, but tends to slow the response   time   to   the   generator.      If rotated  counterclockwise,  the  system response time becomes faster. However, if rotated too far counterclockwise, the generator voltage may oscillate (hunt).  It should then  be  rotated  clockwise  well  above the    point    where    oscillating    occurs. The   system   voltage   stability   is   very critical at no load. (8) Reconnect   leads   to   T1   primary   as they were originally connected. (9) Reset potentiometer R4 to its original position. (10) Disconnect   test   setup   and   reinstall cover. WARNING MAINTENANCE  PERSONNEL  SHOULD EXERCISE    EXTREME    CARE    WHEN TESTING   EQUIPMENT   WITH   POWER ON. b. On-Equipment   Power   Output   Test.   Use   a multimeter to check for the following outputs at   the   F+   and   F-   terminals   at   the   loads specified below: No load - 12V DC at 1.1 amps 250 KW load - 22 V DC at 1.9 amps 500 KW load - 32V DC at 2.8 amps c. Testing of Replaceable Components. Refer to figures 4-8 and 4-9 and check the following components as indicated. (1) Check   diodes   CR8   (29),   CR9   (26), CR13   (30),   CR14   (25),   CR15   (33), and  CR16  (34)  by  disconnecting  one end of each diode and connecting an ohmmeter  (set  at  Rx100)  across  the diode.          Note     reading.          Reverse ohmmeter  leads  to  the  diode  and  not reading again.  A good diode will read high    resistance    one    way    and    low resistance  the  other  way.    A  shorted diode  will  read  full  scale  both  ways and  an  open  diode  will  read  infinity (no reading) in either direction. Replace     shorted     or     open     diodes. Reconnect leads to good diodes. (2) Check   sensing   transformers   T1   and T2   (24)   by   applying   inputs   of   120 volts,  208  volts,  240  volts,  416  volts, 80 volts, and 600 volts. Check with a multimeter  for  31  volts  across  diodes CR5  and  CR2.    Check  for  31  volts across  diodes  CR6  and  CR3.  Check for  31  volts  across  diodes  CR4  and CR1.        If    these    voltages    are    not present    for    all    inputs,    the    sensing transformers   may   be   defective   and must be replaced. (3) After   checking   transformers   T1   and T3,     apply     voltage     to     transformer inputs and verify opening and closing of relay K1 (23) contacts as indicated in   schematic   (figure   4-9).      Remove voltage     and     monitor     contacts     for closing and opening as indicated. (4) Use   an   ohmmeter   to   check   for   1.0 ohms   across   resistor   R25   (21)   and 150 ohms across resistor R1 (9). 4-20.  REPLACEMENT. a. Repair  by  Replacement  of  Components.    If any  of  the  diodes,  transformers,  relays,  or resistors are defective, the voltage regulator is repairable by replacing the defective 4-15