Page 14 - SAFAR

:scanning beam on the sound track. The upper screw rotates the sound reader slightly
and':"thus aligns the beam at right angles to the sound track. Lock the centre screws
on '~ompletion of alignment. Replacement of the exciter lamp may require re-
alignment of the bulb-carrier, which may be done by means of the small screw in the
centre of the lamphouse support. On no account make any attempt to dismantle the
sound-reader unit; as in the case of the objective lens, this may be returned for
major servicing or cleaning.
On no account attempt to reset the flywheel on its shaft; a certain amount of
" float" or backlash is intentionally provided to ensure smooth rotation of the sound
drum and thus give satisfactory sound reproduction. Tightening the flywheel coupling
will give laboured running; if it is too slack the flywheel will bounce.

An unsteady picture will result if the gate slides are fouled by emulsion deposits:
or through incorrect gate tension. Pressure can be adjusted by unscrewing the locking
collar on the gate thrust boss and then screwing in the boss until the picture steadies.
Do not use excessive pressure, nor allow the gate pressure to become too slack.
Tighten the locking collar after adjustment. An unsteady picture can also resu It from
a weakened claw return spring, which should be replaced . Care should be taken to
avoid upsetting the prism alignment when this spring is replaced . Claw-body and cam
wear is automatically compensated for by this spring, so its importance will be
apparent.

LAMP REPLACEMENT : The type of prefocus-capped lamp used ensures that
replacements will not upset lamp alignment with regard to th e optic light path. If
minor adjustment is necessary after a long period of use, this may be accomplished as
follows : with the projector running at fu ll speed , giving as much light on the screen
as possible, focus for a sharp outline of the gate. Slacken the lower pair of thumb
screws on the lamphouse and move them in their slots gently until the light on the
screen is centralised and at its maximum . Lock the screws and then repeat with the
two screws securing the prism. Having ensured that the light on the screen is at its
maximum, obtain an even illumination over the entire image-area by adjusting the
mirror, again by the two mounting screws. This may be carried out with greater ease:
and accuracy by means of a supplementary lens. The idea to aim at is for the gaps in
the image of the lamp filaments to be filled in by the reflections of the filament from
the mirror.

The supplementary lens should be mounted in front of the objective lens and
adjusted until a sharp image of the lamp filament is seen on the screen. Adjust lamp
and prism mountings until the filaments are vertical , centralised and even, but slightly
displaced to one side of the screen. Then adjust the mirror mounting until the
reflected image appears to fill in the spaces between the true image. Use the conden-
ser unit as the datum point in all alignment checks. If the condenser is moved, yet
another variable factor will be introduced, and alignment will become progressively
mo re difficult. The spacing of the lamp from the mirror in a third dimension is
accomplished by the centre screw in the reflector mounting, but this screw should
not be used to move the lamp to within more than I in. of the condenser surface, no r
should it be allowed to distort the lamp radiator shield so that it touches the lamp.