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Simplex XL

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A 35mm projector made by Simplex.


Threading diagram for the Simplex XL. Click to enlarge.

For general information about threading projectors, see threading

  • Using the soundhead flywheel, turn the mechanism by hand to rotate the intermittent sprocket (Item 9) to its "rest" position. In the "rest" position, the index mark (Item 10) will align with one of the painted white index lines on the intermittent shaft collar after the sprocket has completed a four-perforation step.
  • Open the pad roller assemblies (Items 2 & 6). Open the film gate (Item 3) by pulling the gate opening pin (Item 12). Slide the film gate forward to the threading position (as shown). Open the intermittent sprocket show pad (Item 5).
  • At this time, it is advisable to dismount the film gate pressure pad by sliding the gate to its full forward position and removing the (2) button head screws (Item 4). Use a clean, dry cloth to wipe down all film-bearing surfaces of the gate and trap (Item 14). Replace the pressure pad, slotted end down, after cleaning. This procedure should be performed at least once every day.
  • Neutralize the intermittent (or Geneva), make sure the intermittent sprocket is in the center of its travel before threading. See Framing for more details. Thread the film as illustrated. Thread the intermittent sprocket (Item 9) first and check for correct frame position at the framing aperture (Item 13). When correct, close the intermittent show pads (Item 5). Secure the gate by pushing the gate into the trap until the spring-loaded gate latching pin (Item 12) engages. Form two-finger loops above and below the gate as illustrated, and close the pad roller assemblies (Items 2 & 6).
  • Rotate the motor flywheel by hand to advance a few frames of film. Run fingers over each sprocket (Items 1, 7 and 9) to insure that the sprocket teeth are centered in the film perforations, and the film is centered between the flanges of the pad rollers. Check again the position of the film in the framing aperture (Item 13). With the intermittent sprocket in its "rest" position, a correct frame image in the framing aperture insures correct frame positioning in the picture aperture (Item 11). Use the framing knob (Item 8) or handle to correct misframes.
Intermittent sprocket on a Simplex XL projector. Observe its range of motion and set to the center of its travel before threading. See Framing for more details.
  • Thread the soundhead.
  • A slight degree of film tension is required above the feed sprocket (Item 1) and below the soundhead. This measure prevents the film from snapping upon motor start.


History of the Simplex Projector by John Cannon