to disturb the adjusted position of the lamp stand. T h e n
tilt the projector carefully to one side, and tighten two
lamp-stand mounting screws through the holes in the bot-
tom cover plate. Tilt the projector to the other side and
tighten the other two lamp-stand mounting screws through
the holes in that side of the bottom cover plate.
Section IV. FINAL TESTING
60. Test Conditions
a. Tests must be conducted in a darkened room at normal room
b. The line voltage used must be 117-volt (+3 volts), 60-cycle ac.
c. All screen images used in testing the projector must be projected
on a suitable, white, matte screen.
d. Either a 500- or a 1,000-watt, T-20 projection lamp must be used
in making the tests.
e. When tests are made, the projector must be placed on a table or
stand that will insure minimum vibration.
61. Mechanical and Optical Requirements
a. Elevation Knob. When the elevation knob is turned, it should
adjust the angular position of the front surface mirror smoothly and
continuously throughout its range.
b. Focusing Control. When the focusing knob is turned, it should
focus the projector head accurately. The focusing control should
maintain the focusing adjustment at any specific position within its
c. Support-Post Clamping Knob. When this knob is turned clock-
wise as far is it will go, the clamping knob should hold the support
post securely in position.
d. Support Post. The notched end of the support post should fit
firmly over the pin on the locating plug at the bottom of the projector
housing. When it is in position, the post should not rotate on its
e. Shelves. The side shelf of the PH-637A/PFP and the front and
side shelves of the PH-637/PFP should lock securely in place when
raised to the horizontal position.
f. Reflector. The reflector must be positioned vertically and hori-
zontally to insure optimum illumination along the optical axis.
g. Blower assembly. T h e b l o w e r a s s e m b l y m u s t b e s e c u r e l y
mounted to insure minimum vibration when it is in operation. T h e
condition of the fan must insure a maximum volume of cooling air in