HP 8568B, Performance Tests And Adjustments Manual, Page: 165 / 313

3. Preliminary Display Adjustments (SN and Below)
28. Set the oscilloscope controls as follows:
Press
Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . on
amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Press
29. Adjust X POS and Y POS to either extreme to
position the CRT beam off-screen (to prevent possible damage to
the CRT phosphor). If it is not sealed, adjust
INT GAIN
fully clockwise.
30. Adjust the spectrum analyzer’s front-panel INTENSITY control for
peak-to-peak (8 divisions) as indicated on the oscilloscope.
See Figure 3-22.
1
8 . 0 0
4 5 . 0 0 v
10.00 : dc
1 2 5 . 0 0 0
3 7 5 . 0 0 0
5 0 . 0
50.00 v
Figure 3-22. Signal
31. Adjust HF GAIN and for minimum overshoot
on rise and minimum rise and fall times of the pulse waveform.
32. Use the oscilloscope markers to measure the risetime,
falltime, and percent overshoot of the pulse waveform. Rise
and falltimes should be less than 50 ns and 90 ns respectively.
Overshoot on
the
rise should be less than 5% (approximately 0.4
divisions).
33. Set
the
spectrum analyzer’s LINE switch to STANDBY, and center
potentiometers X POSN and Y POSN.
34. Disconnect the oscilloscope channel 1 probe from the spectrum
analyzer. Remove
the
Display Adjustment PC board from the
slot, and reinstall the Intensity Control Assembly.
Replace the Section cover and cables.
35. Perform Adjustment Procedure 4, Display Adjustment (SN
and Below).
Adjustments 3-51