Bell and Howell 1598, User Manual

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P a n chromatic TQIII & TQIII Specialist User Manual
Page
32
Magnetic head replacement.
The magnetic playback head supplied with the projector is for
full width" magnetic soundtracks, it can be replaced with heads for half- width magnetic tracks.
These heads, available from Bell & Howell audio-visual dealers as accessories, are available in two
forms: for a half- width magnetic track on the outer part of the soundtrack area and for a half-
width magnetic track on the inner part. By this means, a film suitably recorded can be given two
alternative magnetic soundtracks, side by side, and either can be selected for a presentation by
fitting the appropriate magnetic head.
60 To change a magnetic head, set the main powor switch to 'off", remove the exciter lamp cover,
then pull off the knob of the soundtrack selector switch.
61 Pushing the magnetic head as far towards the projector as it will go. Rotate anticlockwise until
it is horizontal and pull it straight off its mounting Post.
62 Head replacement is the reverse of the removal procedure. Hold the head with the pin 62a
pointing towards the front of the projector slide it on its mounting post and push it as far as you
can towards the projector. Maintaining this inward pressure, rotate the head clockwise until it
reaches its stop. Release the head, allowing the internal spring to return it to the running position
and finally pulling it gently towards you to ensure that it is correctly seated. Replace the knob of
the soundtrack selector switch, which will fit only in one position, and push it fully on to its shaft.
Replace the exciter lamp cover and set the main power switch to "on".
Cleaning
All external parts of the projector should be dusted from time to time for the sake of its
appearance. Some parts must be cleaned regularly for the sake of the films you will be using.
These are the parts coming into contact with the film, which can easily be scratched as it moves
from spool to spool by even small accumulations of abrasive dirt.
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Picture Gate. Before every presentation and, it the last film shown was dusty, even before
threading another spool, the film gate should be cleaned. Open the main access door and pull
open the lens mount. Brush away all dirt from the rear aperture plate 63a and from the pressure
plate 63b on the lens mount. Films which have not been well lubricated by their supplier may
cause a deposit of emulsion to adhere to the rails of the pressure plate and (more rarely) of the
aperture plate. Inspect these rails carefully from time to time and do so whenever the
characteristic "clicking" sound of the film transport becomes heavier. Remove any deposit of
emulsion, however small If it cannot be dislodged by brushing, use a sharpened match stick, an
orange stick or a piece of hard plastic to scrape it away. Never use any kind of metal object for
cleaning any part of the projector. Brush away any fluff that may have collected around the
apertures in the rear or front plates but do not insert a brush more than 2mm into the rear plate
aperture as this could damage delicate parts inside
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Film Path. Inspection of the projector when it is threaded will show where the film runs and
where, therefore, accumulated dust could cause damage. Wherever you find dust, brush it away.
A "puffer" brush, obtainable from any photographic accessory shop, is useful for this. So, in
certain areas of the projector, is an ordinary pipe cleaner, but care must be taken that the wire in
a pipe cleaner does not scratch any component in the film path.