TM5-6115-593-34 NAVFAC P-8-631-34 T0-35C2-3-463-2 LEGEND FOR FIGURE 4-8 1. Circuit board assy 18. Capacitor 2. Capacitor 19. Capacitor 3. Resistor 20. Resistor 4. Resistor 21. Resistor R25 5. Resistor 22. Bracket 6. Resistor 23. Relay K1 7. Resistor 24. Sensing transformer 8. Capacitor 25. Diode CR14 9. Resistor R1 26. Diode CR9 10. Resistor R3 27. Rectifier CR12 11. Resistor R4 28. Paralleling transformer T3 12. Resistor 29. Diode CR8 13. Capacitor 30. Diode CR13 14. Resistor 31. Rectifier CR11 15. Capacitor 32. Filter choke L1 16. Resistor 33. Diode CR15 17. Capacitor 34. Diode CR16 (shelf)  of  the  AC-DC  control  box  assembly. To    remove    relay,    close    locking    device (under   relay   socket)   and   lift   relay   out   of socket.      To   replace   plug   relay   in   snugly, until locking device is firmly in place. c. Repair.      Repair   relays   K1   and   K50   by replacement  in  accordance  with  paragraph 4-23b. 4-24.      AC-DC   CONTROL   RELAY   ASSEMBLY   TB9. The   AC-DC   control   relay   assembly   (18,   figure   4-10) contains  three  terminal  boards,  two  diodes  (CR1  and CR23), and eight relays: REF. DES. FUNCTION K6 Crank disconnect K8 Low fuel shutdown K19 Overcrank shutdown K20 Emergency stop K22 Main CB control K24 Ether control K40 Frequency selector K54 DC voltage slave a. Test. (1) Check  each  relay  using  test  circuits shown  in  figure  4-12.    Energize  each set   of   relay   contacts   individually   by applying   24V   DC   directly   to   leads. Check for open or closed contacts (no continuity or continuity) as indicated in figure  4-12.    Check  that  each  set  of contacts   revert   (to   either   closed   or open  position)  when  deenergized.    If any relay fails to either open or close as  indicated,  it  is  defective  and  must be replaced. (2) Check    diodes    CR1    and    CR23    for polarity.    A  good  diode  will  read  high resistance  on  way  and  low  resistance the other way.  A defective diode will read full scale both ways, or will read infinity (no reading) in either direction. (3) Check   terminal   boards   and   printed circuit   wiring   by   repeating   steps   (1) and   (2),   but   apply   24V   DC   to   TB9 terminals. b. Repair.    If  any  of  the  relays  or  diodes  are defective,  AC-DC  Control  Relay  Assembly TB9 is repairable by replacing the defective component.    If  the  printed  circuit  wiring,  a terminal board, or a non-replaceable component    proves    defective,    the    entire assembly must be replaced. c. Replacement. (1) Remove relay assembly (18, figure 4- 10) as follows: (a) Tag   and   ten   disconnect   wires from terminal boards. (b) Remove screws (19) to 4-18