Gendex ORTHORALIX 9200 Service Manual page 137

ORTHORALIX 9200 Service Manual
F.6.8 AEC calibration
The calibration of the AEC must be done in the following situa-
tions:
1.
replacement of the pan PA5 AEC control board
2.
replacement of the ceph PA5 AEC control board
3.
a new cassette (panoramic or ceph) has to be used
4.
new intensifying screens (panoramic or ceph) have to be
used
5.
a new cassette (panoramic or ceph) with new intensifying
screens have to be used.
It is important to remember that only the cassettes (with the
own intensifying screens installed), one for the panoramic
and one for the ceph, which are calibrated following this
procedure can be used with the AEC.Using the AEC with
cassettes and intensifying screens that are not calibrated
can generated images with poor quality
The calibration is divided in two steps:
1.
calibration of the sensor mounted on the PA5 AEC control
board: this calibration is necessary to determine if the sen-
sor is working in the useful range, and these parameters can
be used in the future to check that the sensor is working
properly
2.
calibration of the sensor plus the cassette/intensifying
screens used: this is the real AEC calibration and the pa-
rameters obtained during this phase must be stored in the
system.
Case (A): Panoramic AEC calibration
1.
Remove the rear cover of the panoramic cassette carriage.
2.
Mount the brass filter (code 4519 122 25571) on the PA5 AEC
control board so that it covers the AEC sensor; see the figure
below.
Brass filter
Gendex Dental Systems 4519-190-71193-7
F-68
Printed on: 20 Apr 2012, 04:59:40 pm; Printed by: UWE.ZELLER
3.
Check that no cassette is inserted in the panoramic cassette
carriage and remount the rear cover of the panoramic cas-
sette carriage.
4.
Switch on the unit entering the Service Programs, by keeping
pressed the PATIENT SIZE and the DUMMY RUN keys of the
operator panel while switching on the unit.
Keep pressed the two keys till the message WAIT disappears
from the display.
5.
The following message will appear on the display:
SERVICE PROGRAMS
Pls press Y- Y+
where:
to move the rotating arm along the Y axis, to center the
patient with respect to the lateral vertical light).
By pressing the above mentioned keys, select the service
program AEC Slope.
6.
The following message will appear on the display:
AEC SLOPE
DUMMY RUN TO GO
7.
Press the DUMMY RUN key on the keyboard; the following
message appears on the display:
60kV 9mA
8.
Press the RESET key on the keyboard.
9.
Reduce the mA value from 9 to 3 using the mA- key on the
keyboard.
10.
Make an exposure, then the following will appear:
60kV 15mA
11.
Reduce the mA value from 15 to 6 using the mA- key on the
keyboard.
12.
Make an exposure, then the following will appear:
aXX bXX
Write these parameters on a piece of paper.
13.
Switch off the unit.
14.
If one of the two parameters a and b is greater than 255,
repeat the steps from (4) to (13) reducing the value of the
mA of the second exposure till the parameters a and b are
lower than 255. Then, write the three parameters a, b and sl
on the label of the PA5 board.
15.
Switch on the unit entering the Service Programs and select
again AEC slope.
0.80s
0.80s
SL=XX.X
(03.0)E