Wednesday, 11 December 2013

Beaulieu 4008 ZMII





Beaulieu's 4008 ZMII Super 8 camera was first released in 1971, and even though several subsequent models were produced, for many aficionados it remains their best camera - coupled with the Schneider 6-66 zoom pictured above it often tops the list of the best Super 8 cameras of all time. Some of its remarkable features include a fully reflex viewfinder using an oscillating mirror with either ground glass or aerial image viewing, frame rates from 2 to 70 fps, fully manual or automatic exposure with meter film speed settings from 10 to 400 ASA, an adjustable shutter angle, and one of the rarest attributes among Super 8 cameras - interchangeable lenses using a C-mount.  It's also fabulously good looking.

Not all are as enthusiastic about the Beaulieu 4008's charms however. The stubby handle can take some getting used to, the manual controls are confronting to users with little experience, and the custom rechargeable batteries can be expensive to re-cell compared with the many cameras which take off-the-shelf batteries. The most common complaint is that these cameras are unreliable, high maintenance prima donnas that end up spending more time in the workshop than in the field. I don't think any of these complaints outweigh the camera's benefits, in particular the claim of unreliability I suspect comes from users who haven't had their camera properly serviced. A reflex system that uses a mechanically moving mirror and interchangeable lenses will require a little more care and maintenance than a fixed zoom with a built-in prism, but the advantages are well worth it. The issue of re-celling batteries is a problem, but not insurmountable - there is a decent online guide to do it yourself (if you have some basic electrical knowledge), or you can pay around $140 to have it professionally done. Most cameras bought off ebay will need the battery re-celled.

Beaulieu first incorporated the reflex oscillating mirror concept in their 16mm clockwork camera R16 in 1958, and their 8mm MR8 and TR8 models in 1959. The mirror design, body shape, manual controls and solid mechanics of the 4008 series was passed down from these cameras. Compared to many other Super 8 cameras they are relatively easy to disassemble and service, at least to a certain point. By removing the cover plate inside the film chamber (detailed later in this post), speed adjustments and some basic electrical fault finding can be carried out. A copy of the service manual found at the apecity website describes these procedures. This post will focus on the mechanical dismantling and adjustment.






By unscrewing the run button the lens can be removed. Like all C-mounts, it unscrews in an anti-clockwise direction.




To operate the camera, the switch in the handle needs to be depressed first. Sometimes a camera won't run simply because this switch is faulty or needs cleaning. To access it, you first need to peel off the leatherette on the base. A little acetone can help soften the glue.





Then remove the 4 screws holding the base plate.


Dirt, arcing or corrosion between the contacts, or deformation of the parts can cause the switch to fail. I inspect and clean the contacts with electrical contact cleaner and make sure the spring closes both sets of contacts properly when the button is depressed. The button can also be pulled out to activate the switch permanently.




To access the lens mount screws, the plastic cover needs to be pried off. Again, a drop of acetone can help.



If a lens is wobbly it's usually because these screws are a little loose. When undoing them to remove the mount, you'll find some screws are shorter than others. Take note of where the short screws go.




With the mount removed, the mirror can be inspected and cleaned..

..as well as the ground glass. By turning the knob that switches between ground glass and aerial imaging you can see the ground glass move in and out of position. Be very careful cleaning it, the ground surface is easily rubbed smooth and damaged. If an air puffer removes the dust particles then leave it be. If I need to clean it I use a lens tissue with methylated spirit and a single wipe.



I use lens tissue with isopropyl alcohol or good quality lens cleaning fluid to clean the mirror.



Here the mirror is half cleaned to show how much dust and grime it can accumulate.


To take off the control side cover, the ground glass/aerial image selector knob needs to be removed, by undoing the little grub screw in its side, and then the round plate below it needs to be unscrewed. It requires a 2-prong driver or lens wrench to undo (or some needle-nose pliers if you're careful).
I've refitted the mount temporarily to stop it flopping about.









The left screw below the eyepiece needs to be removed.





The control side cover can now be lifted off..







..to reveal the motor, viewfinder and various control and display knobs and dials. Some camera issues may be able to be addressed here without needing to completely remove the mechanism.





Watch out for the declutch plunger found on later models that will fall out when you lift off the cover.




The chrome plating of the battery compartment may be peeling off, with silvery bits scattered around inside. I clean them up and scrub the chrome off that cylinder to prevent further contamination.












To continue on to remove the mechanism completely from the casing, the 2 screws on the front, hidden beneath small leatherette circles, need undoing. These require a 2-prong driver.











The mount is undone, and the foam light seal carefully removed. This will usually have perished and need replacing when we reassemble.











The 3 wires to the mount are de-soldered, after noting which colours go where.





The large screw behind the door is undone.





The 4 wires connected to the handle switch are de-soldered..





..again after noting where each wire goes and making a drawing to help during reassembly.





Then the screw inside the handle is undone and the handle removed.




The 3 slotted nuts at the back are undone, to release the sockets. The topmost charging socket is secured inside, so I leave that one.



The entire mechanism can now be gently wiggled free from the casing. The door and film chamber remain attached to the mechanism. The wires connecting to the charging socket need to be de-soldered to completely remove the casing.











The 2 visible screws in the film chamber can be undone.












To access the other 2 screws the film chamber floor plate needs to be prised up. Acetone run in around the edges helps soften the glue.


Various adjustment pots are accessible under this plate, including the 3 speed pots at the top. By undoing the 2 remaining screws (the far left one under the cartridge spring is tricky but can be accessed by bending the spring down) the film chamber can be removed.


We can now clearly see the gate, with the secondary shutter drive arm attached to the gear at right, and the mirror/adjustable shutter mechanism just below the gate. The light aluminium arm reaching over the top of the gate connects to the filter holder that is just behind the gate aperture. In this position the daylight filter covers the aperture.



When the filter key lever at far right is depressed the arm lifts the filter holder and a clear filter covers the gate aperture. If these wratten filters are damaged or aged they should be replaced or removed. By removing them the lens will focus slightly closer, so the lens back-focus should then be adjusted.


By moving the shutter angle lever at far left the 2 arms of the scissor-like mechanism just below the gate move closer, creating a smaller gap between the 2 parts of the mirror-shutter and effectively reducing the shutter angle. This entire mechanism shuttles back and forth each frame exposure, driven by the arm attached eccentrically to the gear at right.





By peeling off the cover the battery spring contacts can be better accessed. Loose rivets, dry solder joints or corrosion can cause excessive resistance or intermittent power problems. Here I cleaned up and treated the corrosion with a rust inhibitor and re-secured a loose rivet with a pin punch. On the circuit board side I briefly melted the contact solder joints to cure potential dry joints.



To disengage the motor the screw holding this cable clamp needs to be undone so the cable can be pushed aside to access the motor bracket screws below. Note that the footage and frame counter dials have been removed.



I mark the position of the the motor bracket before undoing the screws. Once disengaged the motor can be tested independently, and the movement turned by hand to feel for tight spots with better sensitivity. When re-fitting the motor its position can be adjusted slightly while running the camera to find the point of lowest current draw.
Without a variable power supply to connect 7.2V to the circuit and measure the current, this procedure would be difficult. I avoid supplying voltage to the lightmeter circuit (the 3.6V centre tap going to the rightmost battery contact) while the cover is off to prevent damaging the photovoltaic cell.
To properly access the screws holding the mirror/gate block the control circuit board needs to be removed.




All the wires coming from the right side loom running past the motor need to be de-soldered. Once again, make a drawing to remember which wires go where.





The round cover plate inside the selector knob needs to be removed to access the screw within.





The selector knob removed.





The spring contacts on the knob and corresponding tracks can be cleaned with electrical contact cleaner.




The bottom right screw holding the circuit board also acts as an anchor for the release spring. The spring will need to be re-hooked onto this screw when re-assembling.
The circuit board can now be removed.




We can now start removing the mirror/gate block. I first mark the position of the 'feet' as a reference.





I undo the screw holding the mirror/shutter arm..





..and unhook the 2 springs tensioning the variable shutter mechanism.





The screws holding the secondary shutter arm and claw also need to be undone.




Now we can undo the 4 screws holding the entire shutter/gate block onto the mechanism plate. 2 at the bottom..






..and 2 at the top.


The block removed, showing how the 2 arms of the variable shutter mechanism locate into holes in the 2 sliding parts of the mirror/shutter. Only the right segment is mirrored.
Behind is the secondary shutter, with its timing offset from the mirror/shutter so that the oscillating slit only exposes in one direction, thus maintaining even exposure across the frame.





On the inner side are the gate, the long claw arm, the filter holder and the filter selecting arm. If the filters are damaged in any way, they should be replaced or removed. If they are OK, avoid touching or attempting to clean them with anything other than air.





With careful manoeuvering, the parts of the mirror/shutter can be slid free and cleaned.





The grooves in the block where the mirror/shutter parts slide should be cleaned and lubricated with a very light grease.






The claw pulldown is achieved by a sloping surface against which the claw arm slides. This should also be cleaned and lightly greased.

The last important part to be cleaned and greased is this part of the variable shutter mechanism along which the "scissor" arms slide up and down.

Note the 2 gears at bottom right which drive the shutter and claw - the meshing between them creates the synchronisation of pulldown and shutter timing. If they are removed their position relative to each other should be marked.




With the mirror/gate block removed it is now possible to swing the ground glass out in order to clean the optic behind it, and the back surface of the ground glass if necessary.




Before turning the body over to work on the drive gearing I put some long screws in to act as support feet so the circuitry or ground glass won't get damaged.




To access the drive gearing, the top mechanism plate needs to come off. A small set screw holds the spur gear pictured onto its shaft.



The 1:1 slotted shaft part is pinned. Making sure the part is properly supported, I use a pin punch to drive out the pin. Make sure to note the alignment, this part also acts as a frame pulse signal generator.




Now the screws can be undone and the top mechanism plate lifted off to reveal the drive gearing and take-up clutch beneath.




Remove this pivot arm, which oscillates against the hexagonal plate and indicates in the viewfinder when the camera is running.

2 screws hold the drive gear and clutch assembly onto the shaft connecting through to the cartridge take-up in the film chamber. This assembly is very important, as it allows the take-up to slip rather than pulling on the film while it is being exposed, a major cause of unsteady or jittery imagery. But if it slips too easily, film will bunch up in the cartridge and cause a jam.





Once these screws are undone the shaft can be pulled through and the clutch assembly removed.
2 grub screws lock the threaded triangular spring section at a particular distance (and therefore pressure) from the drive gear. Measure this distance so the parts can be reassembled exactly the same after cleaning. The turning torque on a Super 8 take-up drive should be between 50 and 85g (or cN) measured from a string attached to the edge of a 20mm diameter testing hub. In the absence of such a testing tool and a 100g dynamometer, it's best to just reassemble things as found.






I clean and grease the sliding surfaces of the clutch mechanism before reassembly.

All the bearings can now be accessed and given a drop of oil. Further dismantling of the gearing requires more pins to be removed and probably isn't worth the trouble. As previously mentioned, if the shutter and claw drive gears are removed their meshing position needs to be marked to preserve the timing. During reassembly make sure all the spacer washers go back where they came from. Pictured here is the release mechanism and its spring.





Glue back any cover plates or leatherette with epoxy resin adhesive.



These 3 pots adjust the motor speed relative to the external speed dial, setting minimum, maximum and the curve between. They are accessible from under the film chamber cover plate without needing to disassemble the camera.





A diagram of the wiring to the control circuit board.



When refitting the lens mount it will most likely need a new light seal. An easy solution is to glue a piece of black wool around the edge of the mount. Make sure no stray hairs end up under the mounting surfaces or it will throw out the flange focal depth.





A diagram of the wiring to the lens mount.





I make sure the mounting surfaces are clean before fitting the lens mount.





The top left screw needs to be short or it will bottom out inside.
I check the flange focal depth with a calibrated test lens on a bench autocollimator. This depth is standardised at 17.52mm for C-mount lenses and ensures that the distance scale is reliable and that the focus on a zoom lens remains sharp as the focal length is changed. Because of the in-built filters it is impossible to measure this distance physically with a gauge. The filters also act to extend the back-focus of a lens slightly, so the actual flange depth on a 4008 will be around 17.54mm to compensate.





I also check the ground glass depth, which (reflected off the mirror) must match the film plane depth. The ground glass depth is adjustable via this screw. This setting is very important, as it ensures that what is seen through the viewfinder will match what is recorded on the film.











Once the camera is reassembled a test film should be shot.











17 comments:

  1. Great work Dom! Question, does the eyepiece simply unscrew? Does the camera have to be taken apart to remove? Regards Todd

    ReplyDelete
    Replies
    1. Hi Todd,
      sorry for the late reply.
      Yes the cover needs to be removed to access the eyepiece.

      Delete
  2. Amazing attention to detail. My question is 'where do they find the people with the skills to assemble these?' Are they done on aa assembly line or individually?

    ReplyDelete
    Replies
    1. I would guess it was a combination, with skilled assemblers and testers each focussing on a particular part of the camera.

      Delete
  3. I have a broken 4008 that was part of an ebay lot--I wanted the lenses that came with. I wish I had the courage to take it apart and give it a go. 4008 question. I had the Reglomatic taken off of the 6-66 Optivaron lens by a guy at the photo repair shop. I use a light meter so I have no need of it. But now the macro button is totally loose. Is there an easy fix for that. I still have the reglomatic.

    ReplyDelete
  4. Hello there , mine has an uneven run of the speed, it changes wavering and thus differently exposed frames. Any advice?

    ReplyDelete
    Replies
    1. I have the same problem. Did you figure out the solution?
      According to the service manual,it is a electronical problem, but I cannot figure out how to fix it.
      Any hints would be very, very welcome.

      Delete
    2. Sadly no, I haven't found anyone in South Africa who knows them and be willing to help me.

      Delete
  5. hello, The procedure for removing the internal filter in 5008 s is the same? many thanks

    ReplyDelete
  6. This comment has been removed by the author.

    ReplyDelete
  7. I have to say this is probably the most amazing set of instructions I've ever seen. I have to figure out why my 2008s will not run. Pro8 said they don't work on this particular model. I have no idea why. So at least this gives me a starting point. I really wanna get this camera running.

    ReplyDelete
    Replies
    1. Thanks Sean, good luck with your 2008.

      Delete
    2. There were some subtle differences with the 2008, but without this I would have been flying blind. But I was able to clean it up, maintenance it, and wire it up for external power. I made sure to post those photos so that they will be searchable through google. The more of this stuff out there for others to see, the better.

      Delete
    3. Oh and one thing just perplexed me though. When I removed the handle, hidden was a button that all it does is move the 85 filter in and out. I cant think of a single reason why that would be hidden by the handle. you'd think that would be something the Super 8 film cassette would activate or deactivate. Does the 4008 have this? Its really weird.

      https://www.facebook.com/pg/SDmotionpicture/photos/?tab=album&album_id=1803663962988097

      Delete
  8. Replies
    1. Sorry, I don't service Super 8 cameras any more.

      Delete
  9. Awesome, many thanks Dom!

    As you said, when removing filters, also back-focus has to be calibrated.

    But how? Are there shims somewhere? How to access them when the camera is reassembled?

    The second question: which lubricant do you use? Obviously it must be such that it does not turn into resin as time goes by.

    ReplyDelete