3M
Overhead Projector 9800 Series
Section 3 – Maintenance
3-2
9800 Service Manual
3M 1996
3-1-2. Projection Head Lens, Magnifier Lens
Stage Glass
1. Use 3M
Overhead Cleaner and a soft, lint-free
cloth to clean the surfaces of the head lenses,
magnifier lens and stage glass. Figure 3-4.
Caution
!
Never use paper lens tissues on projection lenses
because they may damage the lens surface.
2. Dampen a soft, lint-free cloth with 3M overhead
cleaner and gently rub surface.
3. Remove excess cleaner and dry surface with a
clean, soft, lint-free cloth.
9800–56I
Figure 3-4. Cleaning Lens, Stage Glass, Body Mirror
3-1-3. Fresnel Lens
In the 9800 projector, the Fresnel Lens is a doublet
lens with a smooth surface on both sides.
Caution
!
Do not clean the Fresnel Lens by immersing or
flushing in water.
1. Remove the Fresnel Lens (see Section 5-2-2 for
instructions).
2. Dampen a lint–free cloth with a liberal amount of
3M overhead cleaner or equivalent (25%
Isopropyl alcohol and water).
3. Apply light pressure and wipe the Fresnel lens in
a circular motion.
4. Wipe dry with a clean cloth or blow dry with
compressed air.