at   the   initial  and  final   ambient   temperatures. NOTE If  the  drift  in  paragraph  d  is excessive,   realign   the   control unit  following  the  procedure  out- lined  in  paragraph   7-8. e.   At   constant   ambient   temperature,   constant   load, constant   voltage   and   constant   barometric   pressure, the  set  frequency  should  remain  within  a  bandwidth of  1  percent  of  rated  frequency  for  a  period  of  4  hours. If  this  bandwidth  has  been  exceeded,   realign   the control  unit  in   accordance  with  paragraph  7-8. f.   If   the   preceding   solutions   to   the   specific problem   do   not   resolve   the   problems,   replace   and repair   the   control   unit,   actuator   (para   13-3   thru 13-8)  or  load  measuring  unit  (para  8-15  thru 8-19)   as   required. 7-3.   Removal. Refer  to  figure  7-1  and  remove  in  the  order  of sequence   numbers. 7-4.   Disassembly   and   Repair a.   Disassemble   electric   governor   control   unit, if  required,  as  illustrated  in  figure  7-2. NOTE Disassembly   and   repair   of   electric governor  control  unit  at  the  field level   is   restricted   to   removal   of the   cover,   connectors,   potentio- meters  and  test  jacks. further disassembly  requires  unpotting  and the   following   disassembly   can   be performed   by   depot   maintenance personnel   only. b.   Remove   cover   and   components   installed   on cover  in  the  order  of  sequence  numbers  (1   thru  15). NOTE Tag  and  unsolder  wires  for  the components  on  the  cover. (1)   Replace   defective   test   jacks,   potentiometers or   connectors. (2)   Repair   procedures   for   individual   wires   of   a wiring   harness   are   covered   in   the   Operator   and Organizational    Maintenance    Manual. c. Remove   six   screws   and   lockwashers   from   cover of control   unit. Lift   cover   slightly slight  angle  to  keep  the  connectors out  of  the  potting  compound. d.   Place   the   complete   unit   in   a trolled  oven,  large  enough  to  allow completely  around  the  unit. 7-2 and  set  at  a and    potentiometers temperature   con- air   to   circulate CAUTION The   melting   temperature   of   the potting   compound   is   165   F.   The flash  point  is  515°F.  Do  not  unpot by  placing  unit  on  a  hot  plate  type surface  or  by  using  an  open  flame. e.   Set   the   oven   temperature   at   180°F   to   185°F and  allow  the  unit  to  soak  until  the  potting  compound is   melted. The   normal   soak   period   at   this   temper- ature  is  11  to  12  hours. WARNING Use  care  when  handling  the  hot  potting compound.   It   can   cause   severe   in- jury   to   personnel. f.   Using   heavy   gloves   and   wearing   safety glasses,   remove   the   printed   circuit   board   from   the melted   putting   compound.   Lift   the   board   s1owly, allowing  the  potting  compound  to  drain  off  the  com- ponents. g.   Set   the   printed   circuit   board   with   transformers on  the  bottom  on  a  drain  board  and  allow  it  to  cool to   room   temperature. h.   Remove   screw   (4)   and   lockwashers   (5)   which attach   connectors   (P1,   J3,   P5,   P2)   to   cover. i.   Tag   wiring   and   remove   harness   (6). j.   Disassemble   remaining   components   mounted on  cover  in  accordance  with  index  numbers  7  through 27. 7-5.  Cleaning  and  Inspection. a.  Clean  all  parts  with  a  cloth  dampened  in cleaning   solvent   Federal   Specification   P-D-680   and dry   thoroughly. b.   Inspect   for   cracks,   breaks,   damaged   connectors, damaged  terminals,  defective  wiring,  and  defective components. Check   potentiometer   for   continuity, resistance,  and  wiring  for  open  insulation. 7 - 6 . Tests  and  Repair. a.  Perform  test  as  outlined  in  figures  7-3  thru 7-10. NOTE Mount  circuit  card  as  shown  in figure   7-11   prior   to   test. b.  Resistance   Test   (50/60   Hz)   .   Refer   to   Table 7-1   and   perform   resistance   test. c.   See   figure   1-4   and   1-5   for   schematic   diagrams. d.  See  table  7-2  for  values  of  individual  comp- onents.   When   measuring   individual   components,   dis- connect   at   least   one   lead   to   prevent   feedback   readings.