TM 1-1500-204-23-4 (2)  Cleaning.    Clean  all  exposed  surfaces with  a  cloth  moistened  in  drycleaning  solvent,  Federal Specification P-D-680, Type II, and wipe dry with a dry clean cloth. (3) Operating procedures.  Refer to TM 55- 4920-229-12 for proper operating procedures. (4)    Maintenance.        Maintenance    of    the Scorsby base is as follows: NOTE The   oil   in   gear   reducer   should flow    slightly    when    petcock    is opened. (a)  When  oil  does  not  flow,  add  oil, Federal  Specification  VV-L-1071,  until  proper  level  is reached. (b)   Lubricate   two   ball   joints   which support   head   of   Scorsby   base   with   grease,   MIL-G- 23827. e.    Pitot  Static  System  Tester.    The  tester  is  a portable,   self   contained   vacuum   and   pressure   tester whose  purpose  is  the  testing  of  aircraft  altimeters,  rate of climb indicators, and fuel pressure gauges. (1) Inspection. Inspect for defects, damaged  leads,  broken  connections,  and  evidence  of leakage. WARNING Drycleaning  solvent  is  flammable and solvent vapors are toxic.  Use P-D-680,   Type   11   Solvent   in   a well-ventilated   area.      Keep   away from open flames. Avoid prolonged    solvent    contact    with skin. (2) Cleaning.  Clean with a cloth moistened in  drycleaning  solvent,  Federal  Specification  P-D-680, Type II, and wipe dry with a clean cloth. (3) Operating  procedures.  Refer to TM 55- 4920-231-14 for proper operating procedures. (4) Safety practices.  Secure all connections to    prevent    leakage    or    loosening    due    to    vibration. Remove     sleeve     from     pitot     tube     and     secure     all connections   to   prevent   leakage   or   loosening   due   to vibration. (5)    Maintenance.        To    ensure    that    the equipment is ready for operation at all times it must be inspected     systematically     so     that     defects     may     be discovered   and   corrected   before   they   can   result   in serious  damage  or  failure.    Defects  discovered  during operation of unit will be noted for future correction to be made as soon as operation has ceased, or operation will be  stopped  if  defect  will  cause  damage  to  equipment, should operation be continued.  After operation, services will be performed at intervals based on normal operation of    equipment,    reducing    interval    to    compensate    for abnormal conditions. Defects or unsatisfactory operation  beyond  the  scope  of  the  operator  to  correct must  be  reported  at  earliest  opportunity.    Maintenance procedures    are    covered    in    applicable    maintenance manuals. f.  Jetcal System Tester.  A jetcal tester, as shown in    figure    4-6,    is    a    portable    instrument    made    of aluminum,   stainless   steel,   and   plastic.      The   major components of the analyzer are the thermocouple, rpm, Exhaust  Gas  Temperature  (EGT)  indicator,  resistance, and   insulation   check   circuits,   and   the   potentiometer, temperature   regulators,   meters,   switches,   and   all   the necessary  cables,  probes,  and  adapters  for  performing all  tests.    The  jetcal  tester  is  used  to  analyze  turbine engines. (1)   Purpose   and   uses.      The   jetcal   tester may be used to: · Functionally    check    the    aircraft EGT    system    for    error    without running the engine or disconnecting the wiring. · Check    individual    thermocouples before    placement    in    a    parallel harness. · Check each engine thermocouple in a parallel harness for continuity. · Check    the    thermocouples    and parallel harness for accuracy. · Check  the  resistance  of  the  EGT circuit. · Check  the  insulation  of  the  EGT circuit for shorts to ground, or for shorts between leads. · Check EGT indicators (either in or out of the aircraft) for error. · Determine   engine   rpm   with   an accuracy of (± 0.1) percent during engine runup.  Added to this is the checking   and   troubleshooting   of the aircraft tachometer system. Change 3  4-7