CPI Canada Inc.
AEC Calibration
3D
Use and disclosure is subject to the restrictions on the title page of this CPI document.
CMP 200
®
Service Manual Ch # 901476-05 Rev. A
Page 3D-17
3D.3.0 AEC CALIBRATION (TABLE BUCKY) Cont
Step
Action
10.
Select the table Bucky image receptor.
Step
Action (membrane console)
Action (PC GenWare
®
)
Action (Touchscreen GenWare
®
)
11.
Select the
Film Screen Cal.
tab.
Select the
Film Screen Calibration
tab.
12.
Select the
75KV
breakpoint. Use the + or
– buttons to enter the value
45
.
Enter the value
4.5
into the
75 kV
dialog
box, under
Film Screen Cal.
Enter the value
4.5
into the
75 kV
dialog
box, under
Film Screen Calibration.
13.
Select the appropriate mA for the first film speed being calibrated per table 3D-8,
remembering that the slowest film screen used in
that installation must be calibrated first
(example 320 mA for 100 speed film). Select large focus, center field.
14.
Make an exposure and note the mAs.
15.
Referring to table 3D-7, select the target mAs required for the film speed being calibrated i.e. approximately 16 mAs at 75 kV for
100 speed film.
16.
Adjust the required gain potentiometer on the AEC board while taking exposures until the mAs noted in the previous step is
obtained.
17.
Load a test cassette with fresh film and install it in the image receptor. Using the same technique as in the previous step, expose
the film and develop it.
18.
Measure the optical density. The desired value should have been previously recorded in a copy of table 3D-11.
19.
If the measured O.D. is not within the desired value, adjust the gain pot to increase or decrease the density, and then repeat the
previous two steps.
20.
Once the desired film density is achieved, record the mAs, calibration number, and O.D. in a copy of table 3D-9.
21.
Vary the absorber thickness, and confirm that the mAs changes accordingly.
STEPS 22 TO 25 APPLY TO SOLID-STATE AEC CHAMBERS ONLY
22.
Measure the mAs with the center AEC field only selected. Record this value.
23.
Select the left field, and measure the mAs. Compare this value to the value noted for the center field.
24.
If the field balance is not acceptable, adjust the left field compensation value up or down as described in the section
AEC Setup
in
chapter 3C such that the left field matches the center field.
Do not adjust the center field (
C
) compensation value.
25.
Repeat steps 23 and 24 for the right field.
