Adjustments; Patient Support Horizontal Leadscrew Adjustment - Zeiss humphrey HFA II-i series Field Service Manual

Adjustment / Calibration
6) Select the REFLEX LED button on the right side of the screen.
7) Set the reflex count located to the right of the REFLEX LED button to 40.
8) Examine the reflex intensity value in the Intensity Reading column on the left side of the
screen. If the reflex intensity is at 31 or higher, use the DOWN STEP buttons to reduce
the intensity until the reflex intensity drops to 30. Now increase the gain using the UP
STEP buttons (in small increments until the reflex intensity is again 31. If the reflex
intensity is below 31 and the reflex count is at 40, use the UP STEP buttons to increase
the reflex intensity until it just reaches 31 if possible. Do not allow the reflex count to
exceed 100. A reflex intensity between 24-31 is acceptable. The higher values within
the range are preferred.
9) Select STORE when the above conditions are set.
NOTE: The <35 count and information are not used in field calibration.
They are for engineering use only.
10) Examine the count for the >35 row of the Intensity Reading column for LEFT and
RIGHT trial lens LEDs. The intensity readings for both should be between 100–200
and should be as close to each other as is possible.
11) If the readings are not in the acceptable range or are not close to each other , select
LEFT LED and/or RIGHT LED and adjust using the UP STEP or DOWN STEP buttons.
Repeat the checks until the trial lens LEDs are equally bright and intensity readings are
between 100–200. The reflex intensity should remain between 24–31. If the reflex
intensity has changed, repeat steps 6 and 7 above.
NOTE: When you adjust the brightness of one LED, the readings from the other
LED also will be affected. Therefore, when you adjust one of the LEDs brighter,
you may have to adjust the other one dimmer in order to get the readings of both
within the desired range of 100–200.
When the desired result is obtained, select STORE.
4.9

Adjustments

4.9.1

Patient Support Horizontal Leadscrew Adjustment

Whenever possible, avoid loosening any of the screws that secure alignment of the forehead
rest lead screw and leadscrew nut. The leadscrew and leadscrew nut must remain accurately
aligned to avoid binding at any point in the range of travel of the nut on the leadscrew. The
preferred means of adjusting tension of the long belt on the patient support assembly is to
adjust the position of the patient support X-motor.
Field Service Guide
Humphrey Field Analyzer II - i
Confidential and Proprietary
4 - 36 52235C1105