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ACL 1.5 mirror parking position


Duncan Brown

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I have 2 ACL 1.5 bodies.  On one of them, when the mirror is centered in the viewing position, the two drive pins you see inside with the motor detached are in the vertically oriented position (6 and 12 o'clock) and so the drive holes in the rubber coupling are horizontally oriented (3 and 9 o'clock).  On the other one, they are exactly opposite (90 degrees out).  Needless to say, taking the mirror-parking motor from one and attaching it to the other does not give me the results I desire!  The motor parks with the pins vertically oriented, meaning it is expecting the drive holes in the rubber coupling in the camera to be at 6 and 12 o'clock.

Is one of the bodies correct and the other wrong?  If so, how is that possible?  Or is there an adjustment on the motor to match it to a given camera body?  (If so it must be inside and not obviously externally accessible.)

Duncan

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Hey Duncan. It's puzzling. Someone who had serviced a lot of ACLs might know if they were all (supposed to be) with the pins in one or other orientation. I wonder how many movement blocks that Heikki has at hand. It would be useful to know if they all have the pins with the same orientation when the mirror is parked (shutter is closed).

Assuming that all factory orientation is the same, I wonder if someone has re-assembled the movement and changed it...and the motor mirror parking somehow.

I would be curious to pull my motor off and look. The camera has only been worked on by Paul at VP so should be factory. But fitting motors and tweaking the mount screws for noise is unappealing.

Anyway, mirror parking's for pussies, what's wrong with an inching knob.

Gregg.

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41 minutes ago, Gregg MacPherson said:

Anyway, mirror parking's for pussies, what's wrong with an inching knob.

Haha, no doubt.  The camera I moved the motor to previously had no mirror parking so if it were assembled "wrong" nobody would know!

The Tobin instructions for mounting their motor to the ACL include the line: "Look at the rubber coupling that is driven by the motor shaft; an imaginary line between the two drive holes should be parallel to the camera base."  OK, sure, but are we talking the drive holes with the pins from the camera drive, or the drive holes that will be receiving the motor's pins?  BE MORE SPECIFIC TOBIN!!  And in any event, their motor does contain an internal way of tweaking that position to wherever it needs to be.

Duncan

 

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36 minutes ago, Duncan Brown said:

.....The Tobin instructions for mounting their motor to the ACL include the line: "Look at the rubber coupling that is driven by the motor shaft; an imaginary line between the two drive holes should be parallel to the camera base." ....

I think that is explicit. With the coupling sitting in the camera, we are looking at the face that is driven by the motor shaft. Oui?

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5 minutes ago, Gregg MacPherson said:

I think that is explicit. With the coupling sitting in the camera, we are looking at the face that is driven by the motor shaft. Oui?

All 4 holes go all the way through the coupler.  So you're looking at 2 holes that are parallel to the base, and 2 holes that are perpendicular to the base.  In two of the holes you can see the shiny ends of the drive pins on the camera drive hub.  Now which two "drive holes" is he talking about?

Duncan

Edited by Duncan Brown
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For what it's worth, your interpretation of the instructions, that the holes he's talking about are the ones that are set to receive the pins from the motor, is how the motorless body is set up.  So if that means the other body is "wrong" then someone has somehow convinced the parking motor attached to it to be "wrong" the same way.  (Which is why I was wondering if there's some secret way to adjust the motors.)

The Tobin motor is not direct drive like the factory motor - there's a belt drive and the way the parking position can be adjusted involves loosening a setscrew on a pulley to change the orientation.  No such arrangement exists on the factory parking motor - any adjustment would have to be electronic I think?

Duncan

Edited by Duncan Brown
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I don't have any original ACL motors but all the mirror parking systems back then worked by using some kind of sensor which reacts to a small shutter or similar connected to the drive shaft and which is in the same position for only once per frame. the electronics are trying to rotate the motor at slow speed and to stop the axle so that the shutter leaves over the sensor.

so there is probably a optical or magnetic sensor somewhere in the motor which opens/closes connection once per revolution if the gear ratio between motor and the movement is 1:1.   By aligning the sensor differently compared to the shutter triggering it, it would be possible to adjust the stopping angle. 

it is possible to do rotation angle calculation with fast microcontrollers and calculate the axle angle without an additional sensor but that kind of technology was not available yet when these cameras and motors were made so there should be a traditional separate sensor somewhere connected to the motor axle.

It sounds like that the other camera body has been opened and has been put back together on different gear alignment than originally intended. Is the movement in sync with the shutter still? 

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Sure, the motor must have a way to detect position, but the motor makes precisely one revolution per frame, so it would be as simple as saying "the motor always stops with the pins vertical" and then setting up the body accordingly.

Both bodies have perfectly synced shutters and mirrors.  It's the relationship between those parts of the mechanism, and the drive pins on the coupler, that are 90 degrees out between the two bodies.

It would be easiest to believe the motor and the body that came with it are correct... and that the other body was put back together at some point by someone who didn't notice they'd done it wrong, because the motor that was on it didn't care.

Duncan

Edited by Duncan Brown
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What SN is on the camera that has the pins incorrectly? The pulldown claw and the pins are very much hardwired together. During servicing one might have to finetune the shutter with the pulldown and then the mirror with the shutter, but touching the pulldown claw? 

I'm not entirely sure if it's even physically possible to get the setting you have if the pieces are the same version as they are in the later models. The claw control shaft is part of the claw control spindle assembly one doesn't normally take apart during servicing. And as it rotates, the claw assembly moves up and down. It's very simple design.

So I wonder: is that an early ACL, where it has been so perhaps from the factory? If it was built before the mid-size base and mirror parking it would make sense.

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Camera number 1643 is in the viewing position when the empty holes in the coupler (so, the drive pins on the motor) are vertical.  It came paired with motor number 1292 which is of the variety with the mirror parking symbol and the speed knob that starts at N and then goes 8 12 50 75 then whatever the position beyond that is.  The motor self-parks with the pins vertically oriented so it works perfectly with that body.  The base is what I believe is called the mid-sized base - wide black slide switch on front with the silver button in the middle.  Has the exposure meter knob, the Jaeger connector, the bloop switch, the fuse, and says "Made in France"  I'll add a picture just so we know which one I'm talking about.

Camera number  641 is in the viewing position when the empty holes in the coupler (so, the drive pins on the motor) are horizontal.  It originally came paired with a (broken) heavy duty motor but the earlier one without the mirror parking.  It has the exact same base as number 1643.  This is the one that when I put the above motor on it, doesn't park in the correct position,  for what is now obvious reasons.

Duncan

 

acl_15_base_01.jpg

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It's hard for me to tell just from the parts diagrams available online but it looks to me like the drive shaft with the hub with the coupler on it has a couple of worm gears on it that could be put in mesh with the rest of the assembly in such a way that the camera mechanism would be synced but the drive pins on the coupler end could be in a few different orientations depending on just how the gears got meshed upon assembly.  Either by someone servicing it, or at a factory where the mirror parking concept didn't exist yet so nobody really was paying attention to that relationship because it didn't matter.

Duncan

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Referring to French parts drawings...and, my assy means assembly

I do have a spare body with the motor off. The empty holes in the rubber coupler are vertical with the shutter open, so horisontal (parallel to camera base) if mirror was parked. So that sounds like the mr Tobin's description.

After reading Heikki, I looked at the drawings and I can't see how the claw control shaft (20) with driving pinion assy (28E) could be assembled 90 deg off without putting the claw 90deg out of phase. 

The only idea I had is wondering if, prior to mirror parking, did randomly oriented driving pinion assys (the gear with the drive pins in the end) exist. The orientation of this assy is set by the hole that is drilled in it for the pin that secures it to the shaft, and of course the drilled hole in the shaft.

If the movement block is out, one can see I think. Assuming the parts drawing is correct, the two pins on the driving pinion assy and the single eccentric drive pin at the other end, for the claw, should all be in plane. But the drawing may be just oriented so to make it easy to read.

Calling on Heikki (again), are all the movement blocks you have, looking at that shaft, with pin orientation as described above...all three pins in plane?  I remember now that you had one or more complete assys of that claw control shaft with gears, bushes etc, removed from the movement block. maybe the photos show it. I'll look.

So, on Duncans skewiff body, the eccentric pin driving the claw will be 90deg out of phase with the pins on the driving pinion.

Gregg

Edited by Gregg MacPherson
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8 minutes ago, Gregg MacPherson said:

..complete assys of that claw control shaft with gears, bushes etc, removed from the movement block. maybe the photos show it. I'll look....

Found that photo, and can't see the pins on the driving pinion, but can see the eccentric driving pin for the claw, and one can see that the drilled hole for the securing pin is at 90deg, just like the parts drawing.

Heikki, is it clear what I'm talking about with the pin orientations on that complete assy?

Gregg.

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37 minutes ago, Gregg MacPherson said:

I do have a spare body with the motor off. The empty holes in the rubber coupler are vertical with the shutter open, so horisontal (parallel to camera base) if mirror was parked. So that sounds like the mr Tobin's description.

OK, but that is like my camera on which the self-parking motor parks in the wrong spot!  My motor/camera combination that works has those vertical when the mirror is centered for the viewfinder operation!  What serial number is your body.  What kind of motor did it come with? (not that that means anything about what kind of motor it originally came with, at this point!)

I wasn't seeing what you guys were talking about with the pin for the claw, but on putting on my 3D brain a little better, I see it now.

I just checked AGAIN, and both these bodies pull the claw down (move the film ) when the shutter is closed, and pull it out of the sprockets and put it back up again (not moving the film) while the shutter is open.

So there's that.

Duncan

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Was talking to someone with an ACL and asked them how their pins were oriented when the mirror was in viewing position.  Holes were horizontal.  So there's another vote for that being correct, and my body and motor that match being the oddballs.

Duncan

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