TB 9-6680-284-35
h. Repeat d through g above until CAL indicator stops blinking with RPM control set
to 900 and 3600.
8. Frequency
a. Performance Check
(1) Connect motional transducer to frequency counter.
(2) Connect motional transducer to 115 V ac source and press pushbutton POWER.
(3) Set range function control to 4000-25000 and adjust RPM control to 25000.
(4) Direct light from TI strobotron into motional pickup. If frequency counter does
not indicate between 2.376 and 2.424 ms, perform b below.
(5) Vary autotransformer from 105 to 125 V ac. Indication on frequency counter
will remain within the limits stated in (4) above. Set autotransformer to 115 V ac.
(6) Repeat technique of (3) and (4) above for control settings listed in table 3. If
frequency counter does not indicate within the limits specified, perform b below.
Frequency counter indications
Test instrument
(ms)
Range function
control
RPM control
Min
Max
4000-25000
15000
3.960
4.040
4000-25000
4000
14.851
15.151
670-4170
4170
14.246
14.533
670-4170
2000
29.702
30.303
670-4170
670
88.665
90.456
110-690
690
86.095
87.834
110-690
400
148.514
151.515
110-690
110
540.054
550.964
b. Adjustments
(1) Set range function control to 4000-25000.
(2) Adjust RPM control to 21600.
(3) Adjust HIGH CAL trimmer for 2.78 ms indication on frequency counter.
(4) Adjust RPM control to 5400.
(5) Adjust LOW CAL trimmer for 11.11 ms indication on frequency counter.
(6) Repeat (2) through (5) above to compensate for interaction of adjustments.
(7) Set range function control to 670-4170 and adjust RPM control to 3600.