Repair Bolex D8L

Repairing the Bolex D8L

A little history

Legendary Swiss camera manufacturer Bolex Paillard introduced their first 8mm "pocket camera" in 1942 . The "L8" is a single lens, single speed camera with a rather small and dim viewfinder. In the 1950s, C, B, and D series models followed, adding twin- or triple-lens turrets, variable-focus viewfinders, multiple speeds, through-the-lens metering, adjustable shutter angle, and rewind functionality. With extraordinary ingenuity, Bolex engineers somehow managed to keep the dimensions the same while constantly adding features!

The culmination of this evolution was the 1961 triple-turret D8LA, one of the best standard 8mm cameras ever made. Although the following repair procedure was done on a D8L (more or less a D8LA without the rewind feature), all compact cameras use essentially the same internal mechanism, so part of this procedure can be used on them as well. This includes the B8, C8 and D8 variants as well as the zoom reflex models P1, P2 and P3.

Servicing Cameras

You may find that many of these cameras run slowly or not at all due to dust contamination and drying out lubricants. Often the winding key feels harsh to turn, or the operating switch is sticky. The viewfinder optics can get hazy and dusty, and the turret is a little difficult to turn. Sometimes the single frame operation doesn't work, or the through-the-lens metering switch doesn't pop up quickly while the camera is running, causing the internal metering sensor to still block the light instead of retracting the film.? But since these cameras are so well made, a little cleaning and relubrication usually They can be restored to almost new condition.

Of course, some damage may be irreversible. If the camera experiences intermittent shaking during operation, the spring may have become deformed and is unable to resume smooth operation. This can happen if the camera is stored with the spring loaded for a long time. If the winding key continues to turn (clockwise) without winding, the spring is most likely broken within its housing (although to be honest, I've never had this happen to a pocket Bolex). Signs of corrosion are a bad sign for any mechanical device and should always be avoided when choosing a camera to buy. But sometimes they can be cleaned back to working condition.

Tools?

It is important to use the right tools when working on any machine, let alone a precision instrument like a movie camera. In particular, make sure the screwdriver is suitable for the screw they are turning. Using the wrong size screwdriver can easily damage the screw head or cause it to slip and damage other surfaces. Most of the screws in the pocket Bolex are slotted, except for the screws that hold the turret and (in later models) the screws that hold the adjustment dial, which have a special head with 4 slots on the edge. If it becomes necessary to undo these, a pair of needle nose pliers is risky but will do the job - I prefer to make the drive by filing out the center of a suitably sized screwdriver so it has 2 prongs that will fit a Slot for screw head.

These should be all the tools you need to repair your camera:

Small, medium and large slotted screwdrivers Needle nose pliers or 2-head screwdriver A pair of tweezers for application A small brush for applying oil A syringe for applying the oil Lint-free cotton swabs Isopropyl alcohol or naphtha Soft-bristled cleaning brush Toothbrush

I also find it very useful A compartment tray for when I'm disassembling the camera Put in the parts. It puts all the screws, washers, and other bits together in the order they were taken out, making it easier to put them back together.

If there is any corrosion, I would use a rust inhibitor product like CRC 2-26 to clean the surface. If there are screws that are difficult to remove, put a few drops on the screw head and let it sit for 10 minutes to loosen it. I avoid using WD-40 in cameras because it has an oily base and can migrate to other areas, especially optics.

Lubricant

I use oil and grease purchased from Bolex, specifically recommended for their cameras, but when it comes to amateur camera lubrication, I don’t think it’s necessary to be so picky . A good quality clock oil (or even sewing machine oil) and a light all-purpose grease will do.

Definitely avoid using silicone spray anywhere near your camera or lens.

Service Procedure

The first step is to run the spring down until the camera stops, then unscrew all the lenses.

Open the door, flick the door lever to open the pressure plate, and pull the pressure plate up and out.

Loosen the screws securing the movement cover.

Remove the movement cover, taking care to secure the top spring roller in place. Notice the direction it bounces and how the little coil springs on the pivot hook at each end. If the roller comes off, you will need to reinstall and properly lock the spring.

Use tweezers or toothpicks to unlatch the spring from the end of the claw arm.

Loosen the screws that secure the claw arms. The eccentric underneath turns when you turn the screwdriver, so you may need to hold it firmly with one hand.

Be careful not to slip and damage the highly polished surface of the gate directly adjacent to it.

Loosen the 2 screws holding the lens counter cover and remove it.

Loosen the 5 screws holding the film chamber plate in place. On some models, the front corner screws are also used to secure the plastic film rails.

Remove the board by lifting the front first. A shaft hidden underneath connects the front of the board to the shot counter on the rear of the body, but when you lift the board it should slide out of the rear connection.

You can now examine the internal mechanisms and even tighten the spring and run the camera to see how it works. Change the camera speed and see how the brass speed regulator on the right works. Before removing anything further, make sure to run the spring all the way down again.

At this point some important components can be lubricated to avoid further disassembly. Nine times out of ten, this will get the camera running fine again, but you won't be able to clean and lubricate the winding mechanism, access the front shutter bearing, or fix issues like a sticky run switch, a failed meter sensor mechanism, or unreliable microcontroller frame operation. Further disassembly also provides better access to the following areas for lubrication, so skip the next three steps if you wish to proceed with a full service.

Otherwise, put a drop of oil under the claw offset. (Do not loosen the screw holding the eccentric to its axis or you will lose shutter/pull-down synchronization.)

Put another drop or two of oil behind the brown helical gear that drives the governor. Ideally, try to get to the other side of the plate where the bearing is mounted. This is the only "ball" bearing in the mechanism and is usually where lubrication is most needed. Try not to get oil on the gear teeth.

Place another drop of oil on each end of the governor shaft.

On the back of the film chamber plate you removed earlier, just below the take-up shaft, is the take-up clutch. This allows the main shaft to slide while the small spur gear below continues to be driven by the gear on top of the spring housing. The take-up spool needs to slide because as more film is wound onto the spool, the diameter increases, so it needs to turn at a slower speed, while the spring's drive speed remains the same.

While holding the spindle on the other side, loosen the screw in the middle of the spur gear. Remove the clutch and note how the gear and friction plate sit on the shaft with the D cutout.

Remove old grease from the friction discs and clean the spindle and its bearings.

Apply some grease to the friction plate surface and put a drop of oil in the spindle bearing. When reassembling, make sure the D-cut is aligned with the shaft. When it's together, hold the spur gear and turn the spindle to make sure it slides smoothly. Another gear on the back of the chamber plate drives the foot counter via a worm gear. Unless it's very hard, I usually don't need to touch it, or the spring bar assembly that keeps the worm gear engaged.

If the turret feels stiff or itchy when rotating, now is a good time to have it serviced. The turret can be removed by removing the center screw. The only thing of note is a spring-loaded ball embedded in the edge of the turret, which locks the turret in three positions. After removing the turret, clean and lubricate the center shaft, springs and balls, and the inside edges of the walls surrounding the turret. At this point, you can reassemble the camera or proceed with a more complete service. If you want to continue, the next step is to remove the front.

To access the screws at the top of the front, the light meter/viewfinder cover must be removed by removing the 3 small screws around the edge. Be very careful with the fragile meter needle when the cover is closed. Now remove the 2 screws on the top front.

There are two more screws underneath the turret that hold it in place at the front

If you have not removed the turret for cleaning, you will need to rotate the turret slightly to gain access to the second turret.

Replace the meter cover to protect the needle, then remove it by sliding it toward the door first. It may take a little shaking to break the painted light seal around the door. Take your time and observe how the front mechanism works with certain parts of your body. When you lift the front, one end of the governor will detach. Also note the small felt strip that blocks potential light leakage through the viewfinder.

Carefully remove any loose parts, such as the speed regulator and rewind gear (if the camera has one). Now we can start removing the spring motor. First loosen the 3 screws on the winder cover.

Now loosen the large screw in the middle that holds the spring motor inside. Once loosened, you may want to hold the motor in place while you loosen the screws completely. The mechanism around the screw allows the winder key to rotate freely in the counterclockwise direction, but holds when turned clockwise. I generally don't think it's necessary to clean and re-lubricate it. After removing the center screw, the mechanism can be removed as a unit.

It's often a good idea to return things to their previous direction. Before removing the motor, make a mark from the square key to the plate around it so you can put it back in its original position.

You can now take the motor out and look at the limit gear on the bottom. These gears allow the motor to wind a certain number of turns before the long gear teeth hit the shallow rake, thus protecting the spring from over-winding. In the other direction, they allow the spring to relax and stop before the spring loses power.

Loosen the screw holding the spring main drive gear and remove the gear.

Loosen the 3 screws holding the winding plate.

Now you can remove the rotary wrap and clean it. Note the location of the outer spring and spring washer. The spring acts as another one-way clutch, allowing the winding plate to rotate clockwise, but not counterclockwise.

Disassemble various parts and clean them. Scrub the springs with a toothbrush to give them a thorough clean

Make sure to clean the cavities in the body as well.

Grease all sliding surfaces, the winding plates and their springs, and the body. When reassembling, remember to position the spring's small protruding hook in the slot.

Clean the drive gear spindle.

Clean the governor pad.

If you move it all the way forward, you can clean the front surface of the variable lens element inside the viewfinder. However, if the back of the element or the inner surface of the eyepiece optic needs cleaning, the eyepiece will need to be unscrewed to gain access. Unscrewing the eyepiece can sometimes be tricky because there's nothing to grab onto, but you can use something like a cut rubber eraser to make a gripping tool. Sometimes a drop of acetone (nail polish remover) helps release it from the surrounding leatherette.

If nothing works, you may have to use pliers, but be careful or you will leave marks. Once removed, you can try cleaning the optics in the eyepiece with a paper towel folded into a sharp point and moistened with alcohol or lens cleaner. But it's a very small optic!

Set the viewfinder focal length to the middle, such as 25mm. Now you can remove the viewfinder cover, lifting it from the back first. The small strip of felt near the door will come off, if it didn't come off before removing the front door.

You can clean the variable elements inside by folding more paper towels into spots dampened with alcohol or lens cleaner. Don't keep using the same paper towels or you'll start staining the glass. A lens blower can help remove dust specks. The mechanism of moving optics usually requires no attention. Replace the cover when finished to prevent dust from entering.

Clean the drive gear with a toothbrush and some alcohol or naphtha. All gear teeth spin dry except for a few helical gears (teeth slanted at an angle) that can be lightly lubricated. So this one has no grease.

Clean the gear teeth on the spring motor.

Put a drop of oil on the drive gear shaft and reinstall the gear. Then reinstall the spring motor (aligning the square key with your mark) and winder assembly.

This next stage can be a little tricky, so only try it if you need access to the running or single frame mechanism, or the gauge sensor isn't retracting properly. Or if you're just curious... First loosen the 2 screws holding the 2 pressure plate bracket springs in place.

Then insert the 2 screws into the door (be careful not to slip and damage the polished membrane guide).

Finally there is this screw, near the bottom of the door.

Then carefully lift the assembly, paying attention to the 2 spacer rings and door gasket underneath.

You can now take a closer look at how the variable shutter mechanism works by sliding the grooved brass helical gear back and forth. Look back at the body and see how the variable shutter dial moves the pin that sits in the groove of this gear. This is a very clever design.

Remove the (now loose) plate using the right-angle arm holding one end of the claw shaft. It is now easy to access the bearings that need oiling. The first is the bearing eccentricity under the claw.

Then there are the ball bearings behind the brown helical gear. By the way, this gear is designed to slide under a certain tension, which is held on the shaft by the friction of a spring washer. This protects the governor from bumpy starts and stops. I have never found it necessary to service that clutch. If you happen to loosen the circlip that holds the gear in place, be aware that the little ball will fall everywhere!

Before reassembly, put a drop of oil on the claw shaft pivot.

..and shutter axis.

If you remove the door gasket, shims and thin cover you will see a rather complex mechanism for the release, selector switch and retractable light meter sensor. If you plan on cleaning and lubricating it, take the time to research it. Many levers are spring-loaded and can pop out of position easily. But cleaning and lightly lubricating them will ensure your camera runs well for decades to come.

When the gate and moving assembly are installed rearward, one end of the gate is pinned in place, but can be slightly repositioned. Try to make sure everything is spinning freely (press the run button) and the shutter isn't scratched. Remember to clean the viewfinder glass cover before reinstalling the front.

You can also clean the governor flange. This surface constantly rubs against the adjustable pads in the body, limiting speed. I greased it lightly with graphite powder, but it's not necessary.

The last step before putting the front back on is to put a drop of oil on the pivots at each end of the governor.

You can lightly grease the helical gears, but try to avoid getting grease on the pivots (or oil on the gear teeth).

Now place the governor back into the body, carefully sliding the front into place and locking the other end of the governor into the bearing. Note that the variable shutter pin lines up with the groove in the gear. Applying some matte black paint to the inner joints will do the job "professionally", although it may be fine without it.

The small strip of felt should be glued or painted where it is installed.

Once the front is back on you can tighten the springs and see how she goes. If there is a problem, you may need to disassemble and reposition the movement components again. But hopefully it purrs like a kitten! Now you can put the chamber cover back on. Attach the size counter shaft to the board and align the other end of the shaft with the hole in the body.

You may need to wiggle the plate a little to get the gear teeth underneath to mesh with the gears on the spring motor. Don't tighten the screws until the board is flat!

Clean and lubricate the claw eccentric shaft before installing the claw. Replace the claw spring, claw cover (make sure the upper roller pops up correctly), and lens counter cover.

Your Bolex is now repaired!