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1) Turn on the FS700. The model number and firmware version
number should be displayed for about three seconds. Then the self-
tests will execute. If any of the tests fail, refer to the
TROUBLESHOOTING section of the manual for a description of
the error messages. Record the test results.
Notch Filter Check
These tests check that the six notch filters are working correctly.
1) Remove the top cover of the FS700. Remove JP104 and insert
JP105-107. This configuration will bypass the FS700's bandpass
filter. Set all notch filters to their extremes, i.e. 40 and 220 kHz. Set
the FS700's attenuator to 64 dB (in CAL MENU 1, press BSP and
TIME keys together). Look at LORAN OUTPUT on the scope.
2) Set the function generator to sweep from 1 kHz to 300 kHz, sine
wave, 200 mV amplitude, and attach signal to right pin of the jumper
JP104 (viewed from front).
3) Tune the frequency of a single filter. Check to be sure that the
notch moves over the appropriate range. Check that the depth of
the notch is at least 20 dB. Record the notch depth. Return the
filter to its extreme.
4) Repeat step 3 for the other filters.
5) If any of the notches are less than 20 dB deep, they may need to be
calibrated.
6) Reset all of the filters to their extremes. Put JP104 back in and take
out JP105-107.
10 MHz Oscillator Check
This test checks the wave shape and amplitude of the 10 MHz outputs
and verifies that the FS700 is not near the end of its electronic tuning
range.
Note
: The FS700 should be turned on and warmed up for at least 1
hour before performing this test.
1) Use the 10 MHz source as the reference clock to the counter.
2) In CAL MENU 2 (press BSP and FREQ simultaneously) set the
oscillator control DAC for 0.
3) Measure the frequency of one of the 10 MHz sine wave outputs. It
should be within ±5 x 10
-8
of 10 MHz. Record the number. If the
difference is greater than the specification, the coarse adjustment
screw of the oscillator may need to be adjusted.
