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Duncan Brown

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  1. Just going by the other HS cameras I've used (I know nothing at all about the Redlakes) they often have other connectors for remote on/off, timing lights, etc. to help with the insane logistics involved in capturing a brief moment in time without a lot of wasted film. So it's possible you could rig up a remote on/off switch through a connector, to take the place of the one missing in the camera body. All the ones I have make rampant use of "military-style" multi pin twist-lock connectors. I have a giant box full of ones I gathered along with the ones I needed, back when I was getting my
  2. Well it's almost certainly something simple, but not necessarily simple to fix! Like, if the contacts deep inside on the other end of that main button were tarnished, say. Maybe some gentle raps on various parts of the camera while holding down the release switch? (Twist-lock the power switch into the always-on position to make it easier to do this.) I deal with old electromechanical pinball machines a lot, and they get angry if they aren't used for years...the fix being to just use them! But sometimes getting that first spark of life out of them is the hard part. Duncan
  3. I would fiddle with the off/battery-test/forward/reverse switch first. Maybe it's not making proper contact in some of the positions (have you tried reverse?). Then maybe the speed knob and fixed/variable speed switch next. Anywhere a contact or variable resistor could have gone open or high resistance with age and tarnish. Maybe fiddle with the takeup and feed spools to see if you can get the movement inside to alter its position even slightly. The R16 has that cool feature where it always stops with the shutter closed, but maybe that also means if something gets old and stops making con
  4. I bought Sean's kit to do the replacement. I'm pretty sure he's morally obligated to discourage you from doing it this way, as it's insane. He also won't help you do it that "right" way on newer cameras because that is also insane and should only be done by a real experienced competent Arri tech. As far as he's concerned, his kit is only for the older cameras with the two bolts holding the transmission. But, here you go. Next tech who disassembles this camera will probably curse the light tool marks I no doubt left on the transmission shaft, but frankly the nut simply wasn't that hard
  5. Oh just another trick I learned along the way. I have a later camera, for which replacing the drive coupler "requires" pretty deep disassembly to be able to hold the transmission in your hands to replace the coupler. That seemed a bit much to ask just to replace a rubber tube, so I figured out a vastly easier way. Just work down through the motor opening! Now, you need to be especially careful not to drop little parts down into the bowels of the camera, so this is not for the faint of heart. But with the right tools, it just took me literally a couple of minutes. At which point I wasn't
  6. As promised. http://backglass.org/duncan/arri/constant_speed_motor_24fps_teardown/ When I get my spare variable speed motor I'll give it the same treatment. With luck it will use the same bearings, so I can go the extra mile and pull them off to parameterize them better. Still wondering about the seemingly spurious number on there. Duncan
  7. OK, full pictures and details coming later, but I got the motor all apart and back together again, and adjusted to about as dead-on to 24fps as you can get with an electro-mechanical governor like that. (I can see why people eventually went to crystal synced motors) For the technological era involved, it really couldn't have been any simpler to adjust the speed, if that's all you need to do. And in the end that was all I needed to do. My bearings were fine, my main brushes were fine, one of the governor brushes is getting on down there but given the level of use I'll give it, will prob
  8. Answered my own question by just doing it - tapped the pack at 6 cells, gives around 8.1V unloaded, still runs at the exact same slow speed. Time for some motor surgery. Duncan
  9. Interesting about the mirror stripes - that actually makes sense! Before tearing down the motor, I actually did a little more testing on the camera. With the battery hooked up and the switch on and the motor out, I can measure the voltage at the motor contact. It's the exact same as at the battery, so I'm probably not losing anything through the camera (yes, it's possible somewhere there's a high resistance that would affect the motor but not my meter, but again I would think that effect would not be so precise as I'm seeing.) BUT!! The voltage is 9.4V. My fully charged nominally
  10. Looks like there is a motor teardown/investigation in my near future! I'll be sure to take pictures. Duncan
  11. Anything tricky about disassembling the motor, or pretty straightforward and is obvious as you get it apart? I'm a whiz at reaplacing bearings in random things, but have never tried to find replacement brushes for a small motor before. Do you have a source? Any insight as to why that's even there? It does seem like it would make the viewfinder image that much less bright when filming. Duncan
  12. It's a brand new one from Sean Charlesworth. Which to be fair, may not act identically to a real Arri one would (if you could still get them), but I'm pretty confident he knows what he's doing. So I'm not ruling that out, but again the absolutely unwavering speed at which it runs makes me less suspicious of things like that, which would likely present as a more erratic result. Duncan
  13. Just realized the red and yellow paint dots on my motor no doubt stand for "2" (red) and "4" (yellow), if you're using the standard resistor banding color code. Not sure if that's an Arri thing or some repair shop thing. Duncan
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