Zeiss humphrey HFA II-i series, Руководство по обслуживанию на месте

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Humphrey Field Analyzer II - i Adjustment / Calibration
Confidential and Proprietary
52235C1105 4 - 39
Field Service Guide
Preparation
P Switch ON the instrument and allow it to warm up to normal operating
temperature (about 15 minutes).
P A transparency CRT overlay template is included in service bulletin HFA2-029(x).
Cut the transparency with a scissor along the dark outer line. It will then just fit
inside of the CRT bezel.
CRT Driver Board Adjustments
V SIZE (Vertical Size)
1)
With CRT overlay template:
Adjust the V SIZE pot so that the display image top
and bottom edges match the top and bottom outline image on the overlay.
WIDTH (Horizontal Size)
2)
With CRT overlay template:
Adjust the WIDTH coil so that the display image’s left
and right edges match the left and right outline image on the overlay.
FOCUS
3) With the main menu still displayed, adjust the FOCUS pot for equal focus at the
outer corners and center of the display.
BRIGHT (Brightness Control)
4) Set the EXTERNAL BRIGHTNESS pot to the maximum of its range.
5) Adjust the BRIGHT pot from minimum brightness towards the maximum bright-
ness. The BRIGHT pot adjustment is correct when the white retrace lines are just
visible.
6) Adjust the EXTERNAL BRIGHTNESS pot towards the minimum position until
desired brightness is obtained.
CONT (Contrast)
7) Turn the CONT pot to minimum brightness (full counterclockwise) and then to
maximum brightness (full clockwise), to determine the range of the pot. Adjust
the CONT pot to its minimum, then turn the CONT pot clockwise about 1/3 of the
total range. After adjusting contrast, it may be necessary to slightly readjust the
BRIGHT pot.
V LIN (Vertical Linearity)
8) From a patient test, adjust the V LIN pot so that the circle encompassing the test
points is circular and not egg shaped.
9) Remove the CRT overlay template and proceed to the Calibration and
Diagnostics menu. Select the Video Test Pattern (Section 4.7) and perform any
final adjustments using this on-screen display.