Hologic DISCOVERY A, Technical Manual

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Discovery QDR Series Technical Manual
4-7
To perform beam alignment:
1. Set the machine in the Center Table position.
Figure 4-6. Filter Drum Adjustments - Top View
2. At the Filter Drum assembly, loosen the jam nuts and insert Allen wrenches (3/
32") in both Filter Drum Allen alignment screws. (Figure 4-6 above shows the
locations of alignment screws and jam nuts.) Ensure that the Filter Drum is run-
ning.
3. Start the X-Ray Survey Utility by selecting Utilities|Service Utilities|X-Ray
Survey (see “X-Ray Survey” on page 9-1 for information on the utility).
4. Set Hi gain to 2, Lo gain to 1 and X-ray mode to 3
5. For Display, click Graph.
6. For Segment, click Air.
7. Click X-ray (F2) to turn on x-rays.
The next 5 steps adjust the beam side to side.
8. Move the front Filter Drum alignment screw until the X-ray signal reaches max-
imum voltage.
Note: The last direction turned should be clockwise to eliminate backlash when
the jam nuts are tightened. The plot should show peak amplitude.
9. Move the rear Filter Drum alignment screw until the X-ray signal reaches maxi-
mum voltage.
WARNING: The X-rays are on. Keep body parts out of the beam.
Adjusting
Screws and
Jam Nuts
Filter Drum Base
Assembly (filter drum
assembly removed)
FRONT