TM   55-4920-402-13&P CHAPTER  2 OPERATING    INSTRUCTIONS 2-1. General. This  chapter  provides  complete  operating 2-2 Controls and lndicators.  Figure 2-l and table 2-l instructions for the VIBREX. Included are illustrations illustrates  and  describes  the  controls  and  indicators  for and  fictional  descriptions  of  all  controls  and  indicators, the  Balancer,  figure  2-2  and  table  2-2  illustrates  and  des- operating procedures, and the use of balance and tracking charts. Troubleshooting techniques for the isolation of tribes the controls and indicators for the Strobex, and figure 2-3 and table 2-3 illustrates and describes the con- malfunctions, other than tracking and balancing rotor blades, are also discussed. trols and indicators for the Tester CAUTION Extreme care should be exercised when ponents and assemblies which may be using the VIBREX test set. This unit easily damaged if subjected to physical contains   delicate   electronic   com- abuse due to improper handling. Table 2-1. Balancer Controls and Indicators Figure & Index No. Control/Indicator Function 2-1-1 FUNCTION  3-position  switch CHANNEL  A  accelerometer  typically  used  to measure  lateral  one-per-revolution  for  main rotor balance. CHANNEL B accelerometer typically  used  to  measure  vertical  one-per- revolution for main rotor track adjustment. Also  used  for  tail  rotor  balancing. TRACK  connects  Magnetic  Pickup  signal  to trigger  Strobex. 2-1-2 IPS  meter Reads vibration amplitude in IPS. Scale no. 1 reads 0 to 1.0 IPS. Scale no. 2 reads 0 to 10.0 IPS. 2-1-3 PUSH FOR SCALE 2 pushbutton Divides IPS meter reading by 10. IPS meter reads 0 to 10.0 IPS. 2-1-4 RPM TUNE dial Tunes  band-pass  filters  to  the  exact  rotor  RPM. 2-1-5 VERIFY TUNE pushbutton Switches the filter from normal to sharp peak con  figuration. 2-1-6 PHAZOR ring-of-lights A phase meter that measures the phase, or clock angle, between the rotor azimuth angle derived  from  the  Magnetic  Pickup  inputs  and the  Accelerometer.  Also  serves  as  power  indi- cator  light. 2-1-7 TEST pushbutton Disconnects  the  Accelerometer  inputs  and applies  the  Magnetic  Pickup  inputs  to  Phazor. 2-1-8 INTERRUPTER  LOGIC  switch The SINGLE position is used when only one Interrupter is installed. The DOUBLE position is used if the swashplate has one Interrupter per blade, one of which is double to provide the   one-per-revolution   azimuth   reference. 2-1-9 RPM RANGE 3-position switch Xl  range  is  999  RPM  range  maximum,  X10 range is 9,990 RPM range maximum, and X100 is 99, 900 RPM range maximum. 2-1-10 MAGNETIC PICKUP switch COMMON  connects  the  two  Magnetic  Pickup inputs together so that both Accelerometer inputs are referenced to the same Magnetic Pickup pulse from the fixed swashplate. The INDEPENDENT  position  is  used  only  if  two Magnetic Pickups are used, as on the left and right  propellers  of  an  airplane. 2-1