BASIC OPERATION
The Linex, Fig. 1, is the only camera ever manufactured by Lionel, the company famous for model trains. Lionel started making the Linex in 1954. The camera accepts a film cartridge for making stereo pairs on 16mm film.

Besides being a collectible camera, the Linex provides a good example of the guillotine shutter. A guillotine shutter usually slides a blade behind the lens. A cutout in the blade provides the exposure. Since the Linex is a stereo camera, the shutter must expose two frames of the film simultaneously—one frame for each lens. This requirement makes the guillotine shutter a good choice; its simple design provides the same exposure for each frame.

The shutter blade in the Linex has two rectangular cutouts. As one cutout in the blade is moving behind one lens, the second cutout is moving behind the other lens. The shutter speed is around 1/60 second.

Cock the shutter by pushing the cocking knob, Fig. 1, toward the release-button side of the camera. You can feel (and hear) the latching action at the end of the cocking cycle. If you don't feel the latch engage, the shutter isn't fully cocked.

The spring-loaded cocking mechanism then returns to the start position; the cocking knob returns to the position shown in Fig. 1. But the shutter blade remains latched by the release mechanism. Push the release button, Fig. 1, to release the shutter. The shutter blade fires across the camera, making two exposures to the film (one from each lens).

An accessory flash unit plugs into the two flash receptacles at the top of the camera, Fig. 1. As the shutter blade travels in the release direction, it completes the circuit between the two flash receptacles. The flash then fires.

Although the shutter speed is fixed, you have a choice between two apertures. Move the aperture-control lever, Fig. 1, to N for normal (f/6) or to B for bright (f/8).

OPERATION OF THE SHUTTER
Remove the complete shutter block by taking out the four screws, one at each corner of the front plate, Fig. 1. Fig. 2 shows the shutter mechanism at the back of the front plate.

The shutter consists of three blades, one on top of the other, Fig. 2:

• The top blade, the cover blade, also serves as the cocking blade.
• The shutter blade sits in the center—it's responsible for exposing the film.
• The bottom blade is the aperture blade—its operation will be clear after we remove the top two blades.

You can still operate the shutter. Cock the shutter by pushing the cocking knob, Fig. 1, to the cocked position. The cocking knob mounts to a post on the cover blade. As you cock the shutter, the cover blade moves from left to right in Fig. 2.

The cover blade now comes against two pins on the shutter blade; the two pins are under the insulator on the cover blade, Fig. 2—you can see the pins by glancing ahead to Fig. 4 which shows the cover blade removed. The cover blade now pushes the shutter blade from left to right in Fig. 2.

When you release the cocking knob, the cover blade returns to the released position Fig. 2—it's pulled by the cover-blade spring. But with the shutter block removed, the shutter blade also returns to the released position; the shutter-blade spring, Fig. 2, returns the shutter blade. If the shutter block were mounted on the camera body, the shutter blade would stay in the cocked position.

You can see what latches the shutter blade by looking at the front of the camera body, Fig. 3. Locate the shutter-blade latch. With the shutter block mounted on the camera body, the lug on the shutter blade, Fig. 2, sits next to the shutter-blade latch, Fig. 3. In the cocked position, the shutter-blade latch then engages the lug on the shutter blade. The shutter-blade latch holds the shutter blade in the cocked position when the cover blade returns to the released position.

Pushing the release button moves down the shutter-blade latch. The shutter-blade latch frees the shutter blade. Now the spring-driven shutter blade moves from right to left in Fig. 2 (which is from left to right in Fig. 3).

Remember that the shutter blade has two cutouts, one for each lens. As the shutter blade moves from left to right, the two cutouts sweep behind the lenses. The two cutouts then uncover two frames of film—one frame for each lens.

It may seem that the two cutouts in the shutter blade would also pass behind the lenses during the cocking cycle. They do. But during the cocking cycle, the cover blade covers the shutter-blade cutouts.

As the shutter blade reaches the released position, the shutter-blade lug pushes up the bounce spring, Fig. 2—that brings the shutter blade to a softer stop. Then, with the shutter blade in the fully released position, the bounce spring latches the lug on the shutter blade, Fig. 2. Now the bounce spring prevents the shutter blade from bouncing and re-exposing the film.

The two pins on the shutter blade also provide the flash synchronization. As the shutter blade moves in the release direction (from right to left in Fig. 3), the two pins brush against the two flash contacts, Fig. 3. Each flash contact goes to one of the flash receptacles, Fig. 1. The shutter blade then completes the circuit between the flash receptacles. As a result, the flash fires.

When the shutter blade moves in the cocked direction, the two pins also pass over the flash contacts. But now the insulator on the cover blade sits above the shutter-blade pins. The plastic insulator prevents electrical contact.

DISASSEMBLY OF THE SHUTTER
1. Remove the nameplate at the front of the shutter block (the plate with the Linex name) by taking out the two screws.
2. An E-clip holds the cocking knob to the post on the cover blade. Slip a small jewelers screwdriver between the cover-blade post and the closed end of the E-clip. Use the jewelers screwdriver to pull off the E-clip.
3. Lift off the cocking knob.
4. Disconnect the end of the cover-blade spring from he hole in the cover blade, Fig. 2.
5. Lift off the cover blade. You can leave the cover-blade spring connected to the front plate.
6. Disconnect the shutter-blade spring from the hole in the shutter blade, Fig. 2. Remove the shutter-blade spring by lifting the spring holder form the slot in the front plate, Fig. 2.

Note: Before removing the shutter blade, you might examine its operation. In Fig. 4, we've moved the shutter blade to the cocked position. Since we've removed the shutter-blade spring, the shutter blade stays where we put it.

When you release the shutter, the shutter blade moves from right to left. The rectangular cutouts in the shutter blade then sweep across the lens openings as simulated in Fig. 5.

7. Lift out the shutter blade, Fig. 5.

Note: Now you can see the aperture blade, Fig. 6. Note the four holes that serve as the aperture. Each lens has one large aperture and one small aperture. Moving the aperture-control lever just shifts the desired aperture size behind the lens.

8. Remove the shoulder screw that holds the aperture blade, Fig. 6.
9. Flex the left-hand end of the aperture blade slightly to disconnect it from the aperture-control lever. Lift out the aperture blade.

REPAIRS IN THE LINEX SHUTTER
There's not much to go wrong with the simple shutter design. Just cleaning the three blades and the tracks in the front plate (the tracks in which the shutter blade rides) should correct most problems. Reassembly is the reverse of disassembly.

If the shutter blade stops with the shutter open, check the insulator, Fig. 2. Rather than sliding under the insulator, the two shutter-blade pins may be catching on the insulator edge.

The insulator may also be at fault if the flash fires during the cocking cycle—in that case, the insulator isn't covering the shutter-blade pins. If the flash doesn't fire during the release cycle, clean the shutter-blade pins, Fig. 4, and the flash contacts in the camera body, Fig. 5. You can take out the complete flash block (the block with the flash contacts) for cleaning by removing the four screws— there's one screw in each corner of the flash block.

REASSEMBLY OF THE LINEX SHUTTER
1. Seat the aperture blade by fitting its fork at the left-hand end over the post on the aperture-control lever, Fig. 6. Replace the shoulder screw at the right-hand end of the aperture blade.

Test: Move the aperture-control lever between the N and B positions; the aperture blade should move freely, changing the aperture size behind each lens.

2. Seat the shutter blade, Fig. 5. The shutter blade should slide freely along its tracks in the front plate.
3. Seat the cover blade, Fig. 2. Fit the cocking knob over the cover-blade post (front of front plate). Replace the E-clip to hold the cocking knob.

Note: A groove in the cover-blade post receives the E-clip. Start the open end of the E-clip in the groove. Then push the E-clip onto the post. Most technicians use needle-nose pliers to seat the E-clip. Place one jaw of the pliers against the closed end of the E-clip; place the other jaw against the cocking-blade post (the side of the post opposite the E-clip). Then squeeze together the pliers to snap the E-clip into its channel. Careful—it's easy to lose or damage an E-clip. Fortunately, you can get generic E-clips as replacement parts.

4. Hook the cover-blade spring to the hole in the cover blade, Fig. 2.
5. Seat the spring holder of the shutter-blade spring within the slot in the front plate, Fig. 2. Connect the other end of the shutter-blade spring to the hole in the shutter blade.

Test: Move the cocking knob to the cocked position; the cocking knob should move smoothly, and the cover blade should move the shutter blade to the cocked position. When you let go of the cocking knob, both the shutter blade and the cocking blade should snap to the released position. At this point in the reassembly, there's nothing to hold the shutter blade. Push against the shutter-blade lug, Fig. 2, to move the shutter blade to the cocked position. Then release the shutter blade—the shutter blade should snap to the released position.

6. Replace the Linex nameplate with the two screws.

Lubricate the lower end of the release button (the end that comes against the shutter-blade latch) with shutter grease, Fig. 3. Lightly lubricate the latching surface of the shutter-blade latch with shutter grease. Use very little grease here—if any grease gets on the blades, the blades will stick together.

7. Replace the front plate on the camera body with the four screws. Thoroughly check the operation.