International projectionist (Jan 1963-June 1965)

cranks hard, remove the drive-roller unit and spin the rollers immersed in a can of kerosene. This will remove caked lubricant. Relubricate as suggested under B2. Check and tighten, if necessary, all electrical connections to the lamp table switch, lamphouse terminal board, carbon holders, control relays, and feed motors. 2. RECTIFIERS AND GENERATORS Remove dust from the interiors of the rectifier cabinets, and see that the cooling fans and automatic switches function properly. Wipe rectifier bulbs and check connections for tightness. See "hat the main switch and relays are functioning well and that the current selector switch and all connections are clean and tight. Turn generator over by hand to note feel of the machine. Blow all dust from the interior with a hand bellows carefulK wipe commutator with a clean, dry cloth. applv a thin film of vaseline to the commutator and wipe off excess to lease onlv a trace. I The color of the copper commutator bars should be a darkish brown, not bright copper color! i If brushes are worn, replace them and "run in" the new ones for an hour after the generator has been lubricated ( Bl I . Check and tighten electrical connections at generator terminals and ballast rheostats. 3. PROJECTOR MECHANISMS Remove am rust-preventative grease that ma) have been applied to exposed metal parts. Drain old oil from gear side, soak up oil from floors of old-style mechanisms, and remove mime from gears and shaft. of old-t \ If* heads b\ scrubbing with a stiff-bristled toothbrush moistened with kerosene. Drain oil from intermittent movement and flush out the oilwell with clean projector oil. not kerosene. No attempt should be made to remove lubricating grease from Motiograph A Vs. however. Blow out dust from heat shields and baffles after removing sight box for easier access. If this is done, i heck framing lamp and replace bulb if blackened. \\ ipe the film gate and rails of each mechanism, also the gate-door tension pads, using a clean, lintless cloth lightlv moistened with cigarette-lighter fluid. Remove all dirt which mav be lodged underneath the tension pads! Clean all aperture plates. Gently remove din from the flanged guide rollers and coil spring bv means of a camels-hair watercolor brush. Be sure to get out all the dirt lodged in the film strippers, swinging the strippers out. if necessary, then replacing in their original position after cleaning. Scrub all sprocket teeth and idler rollers with a toothbrush lightlv moistened with kerosene — but use a clean toothbrush, not the one prev iouslv used for cleaning the gear teeth ! I. SOUNDHEADS CarefulK clean the sound gates of old-style optical soundheads, or the sound scanning drums and pressure rollers of newer models, using a clean, lint-free cloth very lightly moistened with lighter fluid. Remove dirt from the film strippers and clean the sprocket teeth with a kerosene-moistened toothbrush. I Guard against spattering the sound optical lenses. I Clean magnetic soundheads in the same way. and remove deposits of film wax and dirt from the magnetic-cluster surfaces. An orangewood fingernail stick may be needed. 5. MAGAZINE VALVE ROLLERS With the scissors cut along a length of film midwav through the perforations so as to obtain a rough, sawtooth edge. Draw this back and forth through upper and lower valve-roller boxes to catch and draw out In Memoriam R. A. Mitchell It was with great sadness and a sense of personal loss that the staff of the International Projectionist received the word of the death March 28 of Robert Allen Mitchell, the author of so many technical articles we have printed. He will be missed for his personal warmth and great character, as well as for his contributions to projection technology. He was an acknowledged authority in this field, and we feel privileged to have worked with him. stubborn deposits of film dirt. Finish the job with a clean cloth. 6. OPTICAL COMPONENTS l a I Lamp mirrors. Wipe silver-coated mirrors clean with a drv cloth. Use a razor blade to scrape off copper -|ila-he>. If necessarv to use soap and water, moisten the cloth lightlv to avoid wetting the back of the mirror, then rinse with clean water and wipe dry with another (loth. It may be convenient to remove the reflectors from the lamps: if so. do not tighten them excessively when replacing. Badly tarnished or partly cracked mirrors should be replaced with new ones without delay! Clean front-surface "cold" mirrors by first wiping dust awav with a soft, dry cloth, then removing stains and fingerprints with a soft cloth moistened with lenscleaning fluid, and finally wiping the mirror with lens tissue. Silver mirrors may be lightly scoured with steel wool to remove stubborn deposits of scum, but, abrasives should never be used on "cold" mirrors! Scouring soap is helpful for cleaning badly scummed silver mirrors, but avoid any containing chlorine bleach, which may turn the silver coating milky-white if the fumes work through the mirror backing! All chlorine-releasing compounds I hypochlorites I as well as sulfides and cyanides ( in some silver polishes) should be kept far away from silvered arc-lamp mirrors! I b I Heat filters. Remove dust by wiping with a dry cloth, then clean with lens-cleaning fluid and lens tissue. As with front-surface "cold" mirrors, do not scour or scrub — it may scratch the delicate interference coatings, (c) Port glasses. Avoid the use of projector port glasses if possible, but if they are absolutely necessary, treat them very carefully because an image-forming light beam must pass through them. First dust off. then wash with a weak solution of Ivory soap. Rinse with pure water and dry with a soft cotton cloth or lens tissue. (Please turn to page 12) International Proj ectiomst April, 1964