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Rowan Biddiscombe

Bolex EBM Power/Framerate Issue

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Mentioned this in another thread but thought it would be best to start a new one for clarity.

Got a Bolex EBM on a crazy deal and now I'm trying to figure out a way to power it properly. I bought a 12v AA battery box, soldered a tuchel connector and chucked 8x Eneloop Pro batteries (1.2v min.2500mAh) inside. It turns over but it sounds really fast, like 50fps+. The frame rate selector dial does nothing to change speeds oddly.

I guess what I'm asking is: Technically, should this work? Or have I done something wrong? Has anyone heard of the frame rate dial not working?

I'm planning on sending it to Bolex Switzerland for a service but they're understandably crazy busy right now (since a month) and not returning calls/emails.

Any help would be massively appreciated!

Cheers,

Rowan

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Bolex International aren’t busy but abandonded. Marc Ueter has left the company. Otello Diotallevi retired in 2018 and continued to work a little until past May. The new owner, Hugo Diaz, isn’t responding to E-Mails because he is alone. He has no idea of what he bought with the share package on August 28th, 2019. The website is nil. Now he’s taking summer holidays, it is said that he will answer question in September.

Your camera should of course react to changing speed settings. Aapo Lettinen, member here, can help you best. I do only mechanical and optical work (and no Super-8).

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I am more confident making new speed control systems than trying to repair old ones, not being familiar with that particular motor type. 

Is there still technicians working on these motor models able to repair the old electronics? if there is any, that would be the first option to try. 

if you want, I could probably be able to make completely new control electronics to the motor if needed but it would be pretty time consuming and possibly expensive. If you want additional features like additional speeds and a display and so on then it could be useful

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if there is the circuit schematics of the control system available we can try to guess what could be wrong with the camera. 

I have understood that the system is "electrically stabilized" speed control. I am assuming it's reference voltage based. In that case it could maybe just be a mechanical fault in the speed selector or its connections. Just guessing, impossible to know without the circuit schematics. (the way I would do that type of speed selector would be with the selector choosing different reference voltages from resistor bridge which is set up between full voltage and ground. The "stuck" selector would indicate that the resistor bridge does not work correctly so the voltage is stuck to either end of the resistor bridge. For example faulty ground connection on the bridge would do that. This is, again, guessing because I am not sure how they have done the selector, I am basing this guess on how I personally would do that type of design the easiest way) .Opening the camera to show the electronics could reveal some information as well and would give better understanding how the speed stabilizing works on that model. If my guess about the resistor bridge fault is right there could be a mechanical fault which could maybe be even seen and repaired easily. 

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24 minutes ago, aapo lettinen said:

if you want, I could probably be able to make completely new control electronics to the motor if needed but it would be pretty time consuming and possibly expensive. If you want additional features like additional speeds and a display and so on then it could be useful

real Crystal Sync of course with all speed presets being Crystal and very accurate

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