RCA 400 User Manual

TABLE II
16MM LENSES
RELATIVE LIGHT TRANSMISSION
PERCENTAGES
Focal Length
1/2"
5/8"
1"
1-1/2"
2"
2-1/2"
3"
3-1/2"
4"
Speed
f 2.4
f 2.0
f 2.0
f 1.6
f 1.6
f 1.8
f 2.0
f 2.5
f 2.8
Percent
44.5%
64%
64%
100%
100% Reference
79%
64%
41%
32.6%
Placement of Equipment and Spectators
If all the spectators in the room are to have an
unobstructed view of the screen, both the screen
and the projector should be raised above the heads
of the audience. The top of the table upon which
the projector stands should be at least 4-1/2 feet
high so that the beam of light will pass above the
heads of those who sit directly in front of the pro-
jector, and the lower edge of the screen should be
at least as high as the heads of those persons who
sit nearest to the screen.
When a matte screen is used, no one should sit
closer to it than two screen widths, nor farther
from it than six screen widths, nor outside an angle
of 30 degrees from the center line. The most satis-
factory view of the picture is obtained in this area.
Beyond an angle of 40 degrees the picture becomes
noticeably distorted.
When a beaded screen is used, no one should
sit closer to the screen than 2-1/2 screen widths,
not farther from it than six screen widths, nor out-
side an angle of 20 degrees either side of the
center line. Beyond the 20-degree angle the bright-
ness of the screen falls off rapidly.
Choice of Screens
A matte screen should be used whenever a
sufficiently bright picture can be obtained, for it
presents a more uniform brightness to the entire
audience. A beaded screen appears brighter than a
matte screen along the line from the center of the
screen to the projector, but its brightness falls off
rapidly as the observer moves away from this line.
The screen recommendations given in Table III
are based on the use of the RCA 2—inch f/1.6
coated projection lens.
Precautions
In order to avoid interruptions and disturbances
of sound and picture during a show, the observance
of the following details is worthwhile.
Securing Cables
The power and speaker cables should be secur-
ed so that they cannot become disconnected acci-
dentally by persons stumbling over them. They may,
for example, be tied to, or wrapped around, a leg
of the projection table. Where they lie on the floor,
they should be covered or otherwise protected.
Replacements
Interruptions caused by burn-out of the projec-
tion lamp or the sound lamp are occasionally un-
avoidable, but the resulting delay need not be
protracted if the operator always keeps within easy
reach a tested set of spares for immediate sub-
stitution. For details of replacement, refer to
"Maintenance".
Previewing Pictures
An experienced operator will preview films he
plans to show in order to acquaint himself with
their peculiarities and thus be ready to make chang-
es in volume, tone, and focus whenever they are
required.
Care of Film
Film should be handled carefully lest it be
scratched or broken. Film is easily scratched by
winding it too tightly on the reel so that adjacent
turns of film grind against each other. Scratches
on film are very noticeable on the screen and it is
costly and difficult to remove them. Film should be
handled by the edges as much as possible, and
touching the picture or sound track area should be
avoided. Occasionally, film should be inspected
for broken sprocket holes and other defects. Neces-
sary repairs should be performed promptly.
When film is dirty it should be cleaned by pass-
ing it between folds of lint-free cloth moistened
with carbon tetrachloride, or some other cleaner
suggested by the dealer. Consult the dealer for a
humidor for storing film when it is not in use.
Running Time
The running time of reels of given length of
16mm film depends on whether the film is sound or
silent, for sound film runs 24 frames per second
and silent film only 16 frames. Exact knowledge of
the running time of various films will help the oper-

RCA 400 Specifications

General

Power Supply	9V Battery
Type	Multimeter
Display Type	LCD
Dimensions	138mm x 69mm x 31mm
Weight	Approx. 170g (including battery)