15
D: Frequency Adjustment
1. Connect the OUTPUT to an external counter.
2. Set the controls as follows:
FUNCTION TRIANGLE
AMPLITUDE MIDDLE
DC OFFSET OFF
3. Turn the FREQUENCY control knobs to full CW and select
the proper RANGE for a reading of > 1 KHz on the display.
4. Adjust R259 for a 50% symmetry waveform.
5. Turn the FREQUENCY control knob CCW and set the
frequency to 100 Hz on the display counter. It is important
to stay in the same range.
6. Adjust R249 for a 50% symmetry waveform.
7. Repeat steps 5 and 6 for best results on both ends.
8. Select the Frequency range from 10Hz to 100.0Hz.
9. Connect the output to an external counter. Turn the
frequency knob to full CW position. Adjust R211 for a
frequency reading to 102.0Hz on the external counter
10. Turn the frequency knob for an internal counter reading to
90.0Hz. Adjust R637 for a display of 90.0 ±0.2Hz.
11. Turn the frequency knob to 10Hz reading on the counter.
Adjust R638 for a display reading of 10.0Hz ±0.2Hz.
12. Repeat steps 10 and 11 for best result on both ends.
13. Select the Frequency Range to 10MHz. Rotate the
frequency knob to full CW. Adjust C217 for a reading
>10.3MHz.
14. Turn the frequency knob to full CCW, and then adjust R262
for a reading of 50±5 KHz.
E: Output amplitude Adjustment
1. Terminate the output in 50 ohms and connect an
oscilloscope and a multi-meter to the output.
2. With all function pushbuttons out and the knob of
AMPLITUDE control at full CCW position, and then adjust
R401 for output of 0V ±10 mV.
3. Turn AMPLITUDE control to full CW and adjust R450 for
0V ±10 mV.
4. Set the amplitude control to full CW position and select
triangle waveform. Check for a peak amplitude of >10.6V.
5. Set frequency to 10KHz and adjust R225 for a symmetrical
around zero waveform.
F: Function adjustment of Sine wave.
1. Connect a distortion analyzer through a 50 ohms
termination to the OUTPUT and monitor with an
oscilloscope also.
2. Set the FG controls as follows:
FUNCTION SINE
AMPLITUDE MAX
DC OFFSET OFF
FREQUENCY 100 KHz
SYMMETRY OFF
3. Set frequency range to 100kHz and FREQ. Knob for 100kHz
output.
4. Adjust R309 and R320 for minimum distortion and <0.9%.
5. Set frequency range to 100Hz, and FREQ. Knob for 100 Hz
output.
6. Adjust R309 for minimum distortion that should be as
close as to prior value on 100kHz.
7. To check frequency range for 100kHz. If the distortion >
0.9%, to adjust steps 3~ 7 again.
8. Adjust R359/R360 for a round sine waveform of top and
bottom without any peak.
9. Adjust R314 for a symmetrical waveform around zero.
G: Sweep OUT (LOG) adjustment
10. Connect the Sweep OUT to an oscillator.
11. Set the FG controls as follows:
Modulation Knob FCW
Modulation switch OFF
SWEEP Knob FCW
Sweep switch OFF
LIN/LOG ON (LOG)
12. Adjust R533 for a 7V log waveform display.
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