TM 55-4920-328-13 3.    Multi-channel    vibration  meter  2A3.    The multi-channel    vibration    meter    (21,    figure    123)    is    a standard-width,    rack-mounted    unit    that    mounts    four vibration   meters.      The   multi-channel   vibration   meter consists  essentially  of  a  19-inch  chassis  assembly  that simultaneously   monitors   four   vibration   channels.      The vibration   input   signals   are   displayed   on   four   identical meters.    Output  of  each  channel  may  also  be  displayed on  an  external  meter  or  oscilloscope.    Plug-in  filters  are used     in     each     channel     to     eliminate     all     unwanted frequencies  outside  the  range  of  the  frequencies  being monitored.  An on-off switch is located on the rear panel of  the  unit.    The  unit  consists  of  four  identical  sections, each    consisting    of    a    vibration    meter    (22),    FILTER SELECT control (23), RANGE control (24), MODE control (25),   CAL   adjustment   potentiometer   (26),   SCOPE   jack (27),  channel  selector  INPUT  switch  (28),  FILTER  jack (29),  and  SENS  adjustment  potentiometer  (30).    When connected  to  vibration  pickups  mounted  on  the  engine under   test   and   the   power   switch   is   ON,   the   FILTER SELECT  control  is  placed  to  the  appropriate  position  to select  the  desired  filter  for  signal  conditioning  and  the RANGE control is then adjusted so that the meter displays readings at or above the mid-range position on the meter. If  peak-to-peak  displacement  readings  are  desired,  the appropriate  channel  MODE  control  (25)  is  set  to  D  to display displacement in mils.  If average velocity readings are   desired,   the   MODE   control   is   set   to   V   to   display velocity  in  interruptions  per  second.    The  multi-channel vibration meter is used in conjunction with external charge amplifiers   and   filters   (21A,   figure   1-21)   to   extend   its operational   range   for   certain   external   accelerometers. Adjustment   procedures   are   included   in   Chapter   2   with applicable engine test preparations. 4.    Fuel          flow/Oil          consumption          signal conditioner    panel    assembly    2A9.        The    fuel    flow/oil consumption signal conditioner panel assembly (31, figure 1-23)  is  a  rack-mounted  unit  that  provides  a  mounting enclosure  for  a  fuel  flow  signal  conditioner  2A9A1  and  a frequency converter 2A9A2.  The unit consists essentially of   a   signal   conditioner   chassis   assembly   19.00   inches wide,  5.22  inches  high,  and  8.63  inches  deep,  exclusive of   the   left   and   right   track   slides.      The   front   panel   is provided with left and right handles and knurled retaining screws   to   secure   the   unit   in   the   engine   analyzer   sub- module.  Terminal board assembly TB1 is installed on the bottom  panel  of  the  chassis  assembly.    Four  connectors J1, J2, J3, and J4, are mounted on the rear panel of the chassis assembly. a.    Frequency    converter    2A9A2.        The    frequency converter   (58,   figure   7-16)   is   a   unit   used   in   the   oil consumption  signal  conditioner  circuitry  to  convert  input voltages   from   0   to   10   mv   dc   from   2A10   to   output frequencies ranging from 0 to 10k Hz.  Two adjustments, ZERO and RANGE, are provided on one end of the unit. b.    Fuel    flow    signal    conditioner  2A9A1.    The  fuel flow signal conditioner (62, figure 7-16) is an encapsulated    unit    used    to    condition    signals    from    a flowmeter   installed   in   the   fuel   system.      The   fuel   flow signal     conditioner     is     installed     in     the     fuel     flow/oil consumption signal conditioner panel assembly 2A9.  The signal   conditioner   accepts   pulsating   signals   from   the flowmeter at frequencies from 5 to 2,000 Hz and amplifies these  signals  to  provide  an  output  signal  to  the  monitor unit.    The  signal  conditioner  consists  of  a  carrier  pickup module,  a  regulated  power  supply,  a  0.5ampere  fuse,  a stepdown transformer and full wave bridge rectifier, and a 5k  ohm  attenuation  potentiometer.    Excitation  voltage  at 117v ac, 60 Hz is applied to the transformer and rectified to 10v dc at 50ma.  This voltage is applied through a filter network   in   parallel   with   a   10-volt   Zenar   diode.      The nominal   10-volt   output   is   applied   to   the   carrier   pickup module which utilized oscillator, modulator, demodulator, amplifier, and shaper circuits.  Output of the module is the input  to  the  digital  frequency  indicator  and,  through  the frequency  converter  PC5-1A3  (D  to  A).    For  the  vertical tape indicator (1A3), to provide display of fuel flow of the engine  under  test  in  pounds  per  hour.    The  attenuator potentiometer   may'   be   adjusted   to   suit   the   sensitivity requirements  of  the  digital  indicator  unit  which  is  pre-set to the corresponding K-Factor correction. 5.    Oil  quantity  electronic  unit  2A10.    The  oil quantity  electronic  unit  (32,  figure  1-23)  is  a  standard- width, rach-mounted readout unit contained in the engine analyzer sub-module assembly to provide visual indication   of   oil   mass   consumption,   engine   internal   oil integrity, and oil leakage, when connected to an external probe.  The unit is 19 inches wide, 5.22 inches high, and 12.25  inches  deep,  exclusive  of  the  left  and  right  slides. Left and right handles and knurled fasteners are installed on  the  front  panel.    Three  OIL  PROBE  potentiometers: ZERO, DRY, and FULL, are mounted on the front panel. An on-off switch (39), indicator light (40), and a 1-ampere 3AG  fuse  (38)  and  fuseholder  are  installed  on  the  front panel  on  the  lower  left  side.    Connectors  J1  and  J2  are mounted on the rear panel adjacent to eight Change 2    1-39