Figure 3-6. Logo at 6:00 O'clock d. Performance Check of the Strobex Free-Running Mode (Stopped Image). NOTE In  the  free-running  mode,  the  images  will not be stopped except by precise adjust- ment of the Strobex RPM dial. (1) (2) Set Strobex MODE switch to C and RPM dial to 900. Set Tester CAM RATE (RPM) switch to 1800 RPM. Illuminate disc with the Strobex and observe the  logo  in  the  center.  Adjust  the  Strobex RPM dial for a single stopped image of the logo. Verify that the RPM dial reads between 855 and 945. Set MODE switch to D and set Strobex RPM dial to 180 (1800 RPM). Illuminate disc and adjust RPM dial for a  stopped  double  image  of  the  logo. Verify that the Strobex RPM dial reads between  171  and  189  (1710  and  1890 RPM). e. Adjustment There  are no internal adjustments to be made to the Strobex, with the exception of the flash tube focus  adjustment  (para.  3-10.c). 3-7. Accelerometer  and  Magnetic  Pickup  Checkout. The  accelerometer  and  magnetic  pickup,  plus  cables are  checked  during  the  Balancer  checks  in  paragraph 3-5. Balancer FUNCTION switch on positions A and B checks  both  accelerometers.  If  the  Balancer  per- formance  checks  are  not  within  specifications  perform paragraph  3-8  below. TM   55-4920-402-13&P 3-8. Signal Simulator Field Operational Checkout. The Signal Simulator, P/N B4305, will be very useful as it quickly  verifies  all  all  functions  of  the  Vibrex  Text Set. This will quickly isolate the fault to either the cables and transducers or the Balancer/Phazor cir- cuits in unit. a. Performance Check of Balancer/Phazor Circuit. NOTE No other cables are connected to the Balancer  unit.  Signal  Simulator  connectors may  loosen  on  Balancer  cable  receptacles during  testing.  Check  Periodically  and retighten as necssary. (1) Connect Signal Simulator B4305 big cable  connector  into  either  accelerometer cable receptacle and small cable connec- tor  into  magnetic  pickup  cable  receptacle on  Balancer  unit. (2) Connect Balancer power cable to 28 vdc, 3 amps minimum power source. Observe polarity pins A(-) and B(+) if portable dc power supply is used. Verify that at least one lamp in Phazor ring of lights is illuminated. (If not, see Table 3-1). (3) Set the following controls as follows: (a) FUNCTION to A CHANNEL. (b)  MAGNETIC  PICKUP  to  COMMON. (c) RPM RANGE to X1. (d) INTERRUPTER LOGIC to SINGLE. NOTE The  older  Balancer  units  (without  the  A suffix) are switched automatically to Dou- ble Interrupter Logic when the 135M-10 Strobex  is  plugged  in.  Therefore,  Phazor testing and tuning of Balancer unit must be accomplished  without  the  Strobex  plugged in, so as to realize the simple Interrupter Logic. (4)  Adjust  Balancer  RPM  TUNE  dial  to  the lowest RPM (540) reading as shown on Signal  Simulator  nameplate. NOTE When  pressing  VERIFY  TUNE  button, hold button a minimum of 5 seconds due to slow reaction time of Phazor at lower RPM. (5) Press TEST button and check that the Phazor 12:00 clock light is lighted. Release TEST button. (If not, see Table 3-1). Change 4 3-7