SECTION IV. FINAL TESTING
50. Test Conditions
a. Conduct tests in a darkened room at normal room temperature.
b. Use 115 volts, 60-cycle ac line voltage.
c. Project all screen images on a suitable, white, matte screen.
d. Use a 1,000-wvatt, T-20 projection lamp when making the tests.
e. Place the projector on a table or stand that will insure minimum
vibration.
51. Mechanical and Optical Requirements
a. Focusing knob. When turned, the focusing knob should move
the lens mount assembly smoothly and continuously through its range.
b. Pointer Control Knob. When moved, the pointer control knob,
should position the lens mounting tube and the pointer mirror smoothly
and continuously through its range. The knob should remain in what-
ever position it is set.
c. Undcrcarriage Assembly. The undercarriage assembly should raise
or lower the copy feeding unit as required. In the raised position, the
undercarriage assembly should remain against the underside of the
housing. In the lowered position, the undercarriage assembly should
remain in place, tilted slightly to the rear of the projector.
d. Copy Feeding Unit. When the crank is operated, the belt should
rotate smoothly. Single sheets of copy placed on the unit for projection
should be advanced into the aperture area. The vacuum from the fan
should keep the copy flat on the projection stage. When further
advanced, the copy feeding unit should pass the copy out of the
aperture area.
e. Fan and Motor Assembly. The fan and motor assembly must be
securely mounted to insure minimum vibration when in operation.
52. Electrical Requirements
When the power switch is turned to the ON position, the lamp should
light and the fan motor operate. Connect the projector only to an ac
power source.
53. Operational Tests
a. Focusing Test. With the power switch turned to the ON position,
place a sharply defined piece of opaque copy on the projection stage,
and focus the image sharply. There should be no blur anywhere within
the image area. A blur indicates defective components or misalignment
of the optical system. There should be no longitudinal or lateral
chromatic aberration when the screen image is viewed from a distance
equal to twice the width of the screen.
b. Optical Pointer. The arrow should be movable to any portion of
the projected picture area by operating the pointer control knob. It
also should be in sharp focus.
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