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Crystal motor GONE WILD!


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#1 Kristian Schumacher

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Posted 03 December 2009 - 06:06 AM

Hi all,

I just received my new ACL and started testing it out. It has the fixed speed motor with a 25 fps crystal. The manual says to use a 12v battery. I didn´t have one, so I first ran it off a 7.4v Li-Po battery. It ran at 25 fps with no sync warning. But only a light push with my finger would get it to slow down and loose sync. So I hooked it up to two batteries, now giving 14.8v. Again it runs at sync, but can take a lot more resistance before loosing sync. So far, everything is fine. I then decided to run through some feet of exposed film to make sure everythihg is working over time. After a few minutes, the motor speeds up and the lamp comes on. Intermittently at first and then constantly. About double speed (?) When left to cool down, it works again like normal.

Anyone know of this problem? I don´t want it to happen while shooting for real ......

Thanks,

Kristian
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#2 Bernie O'Doherty

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Posted 03 December 2009 - 10:36 AM

It could be the connection from the electronic base at the camera bottom to the motor. The motor has a male 9 pin tiny green plug. The base has the female interconnect. Sometimes you can loosen the three large base screws and manipulate the base position ever so slightly to get a better connection. Hopefully it is something as simple as this.
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#3 Kristian Schumacher

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Posted 05 December 2009 - 12:21 PM

It could be the connection from the electronic base at the camera bottom to the motor. The motor has a male 9 pin tiny green plug. The base has the female interconnect. Sometimes you can loosen the three large base screws and manipulate the base position ever so slightly to get a better connection. Hopefully it is something as simple as this.




Thanks for that Bernie,

I will try to shift the base a little and see if the problem goes away.

Kristian
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#4 Saul Rodgar

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Posted 05 December 2009 - 05:25 PM

I would advise anyone having these issues to be really careful. Disclosure, I am not a tech. That said, first thing I would do is try the motor with a 12V battery, and see what happens, i.e. process of elimination. If it works correctly I would use it with a 12V battery only. If it continues to act up I would check the green 9 pin connection Bernie alludes to or ship it to the ACL tech of your choice before attempting to use it again.

Several years ago, I had a similar problem with a CP mod ACL motor (8-48 fps) paired to its recommended 12V battery. The electronic board fried immediately (with smoke coming out of the motor) after the first 5 seconds of the camera running wildly, but I couldn't make it stop once it ramped up after the 2-3 second. It ran for about 15 seconds after smoke came out of it, but then it was dead. There was a short circuit on the board, triggered by who knows what. It cost me $400 plus to fix it, and for a while it was uncertain if it would be fixable at all, since parts for these cameras / motors are hard to come by.

Edited by Saul Rodgar, 05 December 2009 - 05:26 PM.

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#5 John Sprung

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Posted 05 December 2009 - 06:03 PM

If you're OK with opening it up, do so and look for anything really obvious like loose metal chips or anything burned on the board. Unplug and re-connect any connectors. If it still malfunctions after that, stop running it immediately, and send it to a competent service person.




-- J.S.
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#6 Boris Belay

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Posted 25 January 2010 - 09:27 AM

Hi all,

I just received my new ACL and started testing it out. It has the fixed speed motor with a 25 fps crystal. The manual says to use a 12v battery. I didn´t have one, so I first ran it off a 7.4v Li-Po battery. It ran at 25 fps with no sync warning. But only a light push with my finger would get it to slow down and loose sync. So I hooked it up to two batteries, now giving 14.8v. Again it runs at sync, but can take a lot more resistance before loosing sync. So far, everything is fine. I then decided to run through some feet of exposed film to make sure everythihg is working over time. After a few minutes, the motor speeds up and the lamp comes on. Intermittently at first and then constantly. About double speed (?) When left to cool down, it works again like normal.

Anyone know of this problem? I don´t want it to happen while shooting for real ......

Thanks,

Kristian


Hi Kristian,

I would NOT run a small ACL motor on that high a voltage ! I'm pretty sure I burnt out one of those while fixing it, running it on 13.7 Volt. The Multi-Speed motor can handle higher voltages, but those old single-speed ones seem much more fragile in that respect (perhaps also because of age).

Definitlely try yours with a 12V. battery pack before looking for other possible problems.

Boris
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