4. Final Display Adjustments (SN 3004A and Above)
9.
10.
11.
ASTIG
3D
FOCUS COMP
Press
(
REFERENCE LEVEL
]
and then adjust the reference
level to bring the displayed noise to the top division of the
graticule
Press
and key in 1
dB/DIV. The noise should now completely fill
the
CRT graticule
pattern, illuminating a large rectangular area. If necessary, adjust
the reference level until the graticule pattern is completely filled.
Press SWEEP
[SHIFT) DISPLAY LINE
and then
THRESHOLD
to turn off the CRT annotation and
graticule pattern.
Connect a 56503 photometer probe to the Tektronix J-16 digital
photometer. Set the photometer to the Xl range.
Place the photometer light probe hood against the IF-Display
Section glass
filter, and adjust
INT GAIN for a
photometer reading of 80 NITS
This reading must be made with the glass
filter in place in front of
the CRT. It might be necessary to slightly trim the top and bottom of
the photometer probe’s hood so that it will fit flush against
the
glass
filter.
If a standard J-16 photometer is used (instead of metric option
adjust
for a photometer reading of 23.5 fl (foot-lamberts).
12. Set the spectrum analyzer LINE switch to STANDBY and then
back to ON. The spectrum analyzer power-up annotation should
be visible on the CRT display. (This includes the firmware
datecode.)
13. For the best focus near the center of the CRT display, adjust the
following potentiometers in the sequence listed below. Repeat as
needed to optimize center-screen focus.
FOCUS LIMIT
ASTIG
3D for best focus of annotation (short vectors)
FOCUS COMP for best focus of graticule lines (long
vectors)
14. Adjust
FOC for best focus at the top and bottom of
the display.
15. Adjust
R/L FOC for best focus at the right and left
sides of the display.
16. If the top and bottom (or right and left sides) of the display
achieve best focus at different potentiometer settings, adjust
T/B CTR or
R/L CTR, and then readjust
T/B FOC or
FOC to optimize overall
focus.
Adjustments 3-67