TM 5-6115-593-12 TO 35C2-3-463-1 (2) Plug   test   set-up   into   120V   AC   power supply. (3) Observe that neither of the 120V AC test lamps light. (4) Depress  and  hold  pushbutton  A;  lamp  A should   light   and   lamp   B   should   remain extinguished. (5) Release  pushbutton  A  and  depress  and hold pushbutton B; lamp A should extinguish and lamp B should light. (6) Depress  and  hold  pushbutton  A  and  then also depress and hold pushbutton B; note that transfer does not take place. (7)    Wire  contactor  K109  into  test  set-up  as shown in figure 4-14. (8) Plug   test   set-up   into   120V   AC   power supply. (9) Observe that test lamp does not light. (10) Depress  and  hold  pushbutton;  test  lamp should light. (11) Release    pushbutton;    test    lamp    should extinguish. (12) Refer    to    next    higher    maintenance    for repair of any defective contactors. c. Replacement.  Replace defective contactors as follows: (1) Remove  contactors  K107  and  K109  (54) by  disconnecting  and  tagging  lead  wires, and   removing   screws   (52)   and   washers (53). (2) Remove contactor K108 (51) by disconnecting and tagging lead wires, and removing screws (49) and washers (50). (3) Install   contactors   K107   and   K109   (54) using   screws   (52)   and   washers   (53)   to secure   contactors   side   wall   of   external power enclosure (94).  Connect wires and remove tags. (4) Install  contactor  K108  (51)  using  screws (49) and washers (50) to mount contactor. Connect wires and remove tags. 4-24.  MAIN CIRCUIT BREAKER CB2. a. Inspect.    Inspect  main  circuit  breaker  CB2  (44, figure   4-12)   for   loose   or   broken   wires   and damaged case. b. Removal.      Remove   circuit   breaker   CB2   (44, figure 4-12) as follows: WARNING Set  MAINTENANCE  LOCKOUT  switch to MAINTENANCE LOCKOUT. Disconnect negative cable from batteries.    Remove  external  power  by opening    CB101    and    disconnecting. Load terminals of generator set circuit breaker  (CB2)  may  still  be  energized with  the  bus  voltage.    (1)  Disconnect input bars from reconnection panel to CB2. (2) Disconnect buss bars (40, 41, and 42) by removing    bolts    (37)    and    screws    (35), washers (38) and nuts (39). (3) Free upper set of circuit breaker buss bars by removing fastening hardware. (4) Remove   circuit   breaker   CB2   (44)   from enclosure  (99)  by  removing  eight  screws (38). c. Test.      Refer   to   figures   4-14   and   4-15   and proceed as follows: WARNING Disconnect   all   input   bars,   bussing, cables  and  control  circuits  to  breaker before starting test procedure. NOTES 1. Manual operation of circuit breaker disorders the sequence of electrical control, Do not attempt to operate    the    breaker    from    OPEN    (OFF)    to CLOSED (ON) without energizing the undervoltage trip.  To restore electrical mode of operation,    the    breaker    must    be    cycled    into CLOSED   (ON)   or   OPEN   (OFF)   position   as indicated on motor cover. 4-44