HP 8560A Service Manual page 49

Procedure
1. Set the analyzer's @ switch off. Remove the analyzer's cover and fold out the A2
Controller and A3 Interface assemblies as illustrated in Figure 2-2. Connect the CAL
OUTPUT to the INPUT. Adjustment locations are shown on the CRT neck for Al7
adjustments and in Figure 2-4 for the A2 adjustments.
Preliminary Adjustments
2. Set A17R55 X GAIN, A17R75 Y GAIN, A17R92 DDD, A17R93 ASTIG, A2R206 DGTL
X GAIN, A2R215 DGTL Y GAIN, A2R262 STOP BLANK, and A2R263 START
BLANK to midrange. Also set the rear-panel X POSN, Y POSN, and TRACE ALIGN to
midrange.
3. Set A17R21 Z FOCUS, A17R26 X FOCUS, and A17Rll CUTOFF fully counterclockwise.
4. Set A17R4 Z GAIN fully clockwise.
5. Turn the analyzer on and allow it to warm up for at least 3 minutes. Adjust A17Rll
CUTOFF until the display is visible and A17R34 COARSE FOCUS for best possible
focus.
Cutoff Adjustment
Press
FOCUS
line between the bottom of trace A and the annunciators at the bottom of the display just
disappears.
Deflection Adjustments
MORE
8. Refer to Figure 2-3 for locating the lines used for adjusting DGTL X GAIN and DGTL Y
GAIN. Each of these lines is actually two lines adjusted for coincidence. The two lines will
form an "X" if they are not adjusted properly.
9. Adjust A2R206 DGTL X GAIN until the two vertical lines near the left edge of the
display appear to be one single line.
10. Adjust A2R215 DGTL Y GAIN until the two horizontal lines near the top edge of the
display appear to be one single line.
11. Adjust A2R262 STOP BLANK and A2R263 START BLANK for the sharpest corners of
the outer box in the test pattern. The intensity of the corners should be the same as the
middle of the lines between the corners.
12. Adjust the rear-panel TRACE ALIGN until the leftmost line of the test pattern is parallel
with the CRT bezel. See Figure 2-3.
13. Adjust the rear-panel X POSN and A17R55 X GAIN until the leftmost 'Q" characters
and the softkey labels appear just inside the left and right edges of the CRT bezel.
STORE FOCUS GRAT OFF.
PATTERN
. Fold up the A3 Interface assembly.
2. Display Adjustment
Adjust A17Rll CUTOFF until the
Adjustment Procedures 2-15