thermostatic switch turns on the blower until the temperature drops to a
preset point and then shuts off the blower. When turning off this type
of overhead projector, leave it connected to the electrical outlet until
the blower has stopped.
(2) Projector lamps.
Overhead projectors have two lamps.
When
the primary lamp fails, turn off the projector and change lamps by
sliding the lamp change lever to the secondary lamp position. Replace
the primary lamp as soon as possible. The projector has a lamp indicator
light that lights when using the secondary lamp.
When using this projector to show special viewgraphs or using it with a
screen that has a problem with the ambient light, you can increase the
light output by 10% by placing the lamp intensifier switch to the high
position. You must realize that placing the lamp intensifier switch in
the high position reduces the life of the lamp by approximately one half.
Occasionally, you find the image on the screen has red or blue corners.
To eliminate this undesirable effect, use the optical tuning wheel to
decrease the aperture opening of the projector. You also can use this
control to adjust the projector to different size screens.
(3) Removing and replacing a lamp.
These projectors use an ENX
lamp with a life of about 170 hours at high intensity or 370 hours at low
intensity. When a lamp has failed, allow the projector to cool before
replacing the lamp and disconnect it from the power source. When the
projector has cooled, rotate the optical tuning wheel counterclockwise
until it stops turning. Then push the button to release the access door
and open the door. Next you pull the lamp ejector lever toward the rear
of the projector to release the burned out lamp from its holder and lift
it out. Insert the new lamp in the holder, ensuring you wipe off any
fingerprints. The body oils on your fingers stain the lamp and cause hot
spots that cause the lamp to burn out or break.
Once you have installed the new lamp, plug in the projector and turn it
on. With the lamp lit, eliminate any red or blue corners on the screen
by adjusting the optical tuning wheel until the image on the screen is
white.
(4) Cleaning the projector. To ensure the best possible image on
the screen, clean the outside lenses of the projector head and the top
surface of the optical stage. Use a mild detergent solution and a clean,
soft, lint free cotton cloth, and rinse and dry the surfaces. You cannot
use a paper towel to clean these surfaces because paper towels are
abrasive and will scratch.
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