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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