3M
Overhead Projector 9800 Series
Section 4 – Adjustments
4-3
9800 Service Manual
3M 1996
4-2.
Optical Alignment
Proper alignment of the optical system is essential for
good resolution and uniform illumination. Poor
resolution in one corner and either red or blue in the
corners of the projected image are indications of poor
alignment. The following components should be
checked and adjusted to correct any alignment
problems:
•
Lamp Position
•
Post Alignment
•
Head Alignment
Square Image
Centered Image
•
Color Tuning
4-2-1. Lamp Position
Check the lamp position to verify it is aligned and
centered in the optical path.
1. Push power switch On then Off again to
illuminate lamp.
2. As the lamp image fades out, look in the
projection mirror. The lamp filament and its
reflection should be aligned and centered squarely
in the optical path. Figure 4-4.
!
Do not look directly into the projection mirror
when the lamp is fully illuminated. Wait until the
lamp image has faded.
Sight
Through
Mirror
9800–58I
Aligned and Centered
Not Aligned
Not Centered
Figure 4-4. Lamp Aligned In Center of Optical Path
3. If the EVD lamp filaments are not aligned, seat
the lamp squarely against the lamp socket and
check the alignment again.
4. If the lamp cannot be centered, by reseating it,
check the post and head alignment.
