Part 2. The Basics |
Chapter 6. Preventive Maintenance
Preventive
maintenance is very important. It can make the difference between having
a
reliable projector that will go on and on indefinitely, and a machine that
drives you
crazy because of its unpredictability.
Belts
Keep
an eye on the drive and arm belts. Every so often, remove them and wipe them
thoroughly with a dry cloth. This gets rid of any oil or grease they might have
acquired.
It also gives you a chance to inspect them for signs of deterioration.
While the belts
are off, clean the pulleys, give the bearings a little oil and
rotate them a few times.
Before replacing the belts, make sure all excess oil is
removed.
Lubrication
Too
much oil is the most common problem with projectors. Stray oil can gum up
motor
brushes, destroy insulation and clog sound systems. For this reason, user
manuals used to indicate that all lubrication should be left to trained
technicians.
As experts are now very thin on the ground, you will have to work
out your
own lubrication schedule. The information in Part 5 may help.
Use
the highest quality products available. Use minimal amounts. A smear of grease
on the drive gear is enough; there is no need to smother the cogs. On a
projector
that is used only once a week, one drop of oil on a bearing is likely
to be too much.
The vital thing is to keep checking all moving parts regularly
to make sure the
lubrication is still there and doing its job. Perhaps once a
year clean off all grease
and replace it. It’s not a bad idea to take the
rollers off and clean their bearings too.
This gets rid of any dust and grit
that may have accumulated. Don’t touch sealed
bearings. If you are concerned
that they haven’t been looked at for thirty or
more years, refer them to a
specialist (see Chapter 7 - Resources). But they
are probably still in excellent
working order and good for another thirty years.
Cleaning
Cleaning
the film path is discussed in detail in the Procedures chapter. However,
the
rest of the projector needs attention from time to time. If unattended,
dust can
build up in unseen crevices and corners. Overenthusiastic lubrication
can result
in oil and grease being sprayed all over the interior workings of
machines, and
dust just loves oil and grease. Keep your projector clean all
over, inside and
out.
Reels
Metal
reels are tough and reliable. They don’t warp and they don’t break easily.
Unless they are badly bent, they don’t grab. But they are heavy, and if you
are
screening a big reel the extra load on the projector will not help its
performance.
Plastic
reels are light and under most circumstances perform very well. But if
they are
not in good condition they tend to grab film, and this can really spoil
your
day. Over time, the sides of plastic reels have a natural tendency to move
inwards towards each other. You can help prevent this happening by storing
reels
properly.
An
empty reel should never be laid down flat, as the top side will gradually
droop,
narrowing the gap between the two sides. If used on a projector it
will grab
film and be useless. For the same reason, empty reels should never
be stacked
flat on top of one another.
Reels
should be stored hanging vertically from a peg. Even better, before
you hang
them up, cut strips of strong cardboard 18 mm wide and insert
them between the
sides of each reel, winding them around for at least a
full circle. This
maintains the gap between the sides.
Rejuvenating
Reels
Plastic
reels that grab film can be restored to usable condition. Cut strips
of
cardboard 18 mm wide, insert them between the sides of the reel, hang
the reel
up and forget it for a few months, the longer the better.
Distorted metal reels
are, unfortunately, beyond salvation.