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BFD acting up. Bad cable?


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#1 Jess Haas SOC

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Posted 09 July 2009 - 12:22 AM

While shooting today my BFD stopped working a couple of times. The unit itself seemed to have a connection and start/stop worked fine but turning the knob did not turn the motor. When this happened the first time I disconnected the motor from the lens and it was again working fine. The second time a tap on the side of the motor returned it to functioning normally. Sounds like a bad connection either in the cable or the motor to me but there could always be some other gremlins involved.

The motor just returned from being serviced by Heden where they replaced the motor(the one inside the motor) with a new one so a bad solder connection there is a possibility(or even worse, a bad motor). I have another cable but wasn't able to switch it out on set because it was back at basecamp and we were a ways away. I am going to swap the cable and if that doesn't work open up the motor and check things out in the morning, but I just wanted to see if anyone had any other thoughts. I am hoping I can actually reproduce the problem at home, this is the type of thing that only seems to come up when you least want it to. The handset itself was recently dropped onset when somehow the metal piece that the neckstrap connects to came unscrewed. Seemed to still work fine at the time and for a few shoots since so I don't think it is the culprit, but you never know.

Thoughts?

~Jess
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#2 Robert Starling SOC

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Posted 09 July 2009 - 10:26 AM

While shooting today my BFD stopped working a couple of times.


Hey Jess, did you try using a different frequency combination or is there a possibility your transmitter or cabling (if using one) is too close to each other?

Robert
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#3 Todd Ferguson

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Posted 09 July 2009 - 11:33 AM

Jess, check the pins inside where the cable connects to the motor. Sometimes the inside gets pushed up inside the housing and makes an intermittent connection or none.

Todd Ferguson.
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#4 Louis Puli SOC

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Posted 09 July 2009 - 06:20 PM

Quote" The handset itself was recently dropped onset when somehow the metal piece that the neckstrap connects to came unscrewed. Seemed to still work fine at the time and for a few shoots since so I don't think it is the culprit, but you never know".

Thoughts?

~Jess
[/quote]
Hi everyone
After my assistant also dropped the handset because of that small metal piece holding the neckstrap I have now used "lock-tight" on all my handsets and seems to have stopped that problem .
Jess I had a intermittent problem again after it had been droped I would open the handset and check that the "chip" is still in place .
Good luck
Louis Puli
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#5 Jess Haas SOC

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Posted 10 July 2009 - 06:45 PM

I was planning on putting some locktight on there myself. Jim, maybe you should do that with new ones as well? Looks like I am not the only one to have the problem.

Still haven't gotten around to diagnosing the problem. Been busy with that non film related real life excitting stuff like cleaning the bathroom.

~Jess
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#6 JimBartell

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Posted 11 July 2009 - 01:12 PM

I was planning on putting some locktight on there myself. Jim, maybe you should do that with new ones as well? Looks like I am not the only one to have the problem.

The post need to be removable so you can use the "Butterfly" bracket to attach two hand units together. We do use a locking washer but these can loosen up over time. If you never plan to use a second unit feel free use a little Loctite yourself, but I can't do it here.

Jim "Loc n' load" Bartell
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#7 Jess Haas SOC

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Posted 11 July 2009 - 01:36 PM

Makes sense. If I were to use locktite it would be the break away kind and not the permanent. Never noticed a lock washer on my hand unit but it most likely got lost when it fell off. Got any pictures of that butterfly bracket btw?

And it looks like Todd Ferguson is the winner. Looking at my motor it looks like two of the connections on the connector got pushed in just enough to cause an intermitant problem. Opening it up right now to try to fix it.

~Jess
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#8 Jess Haas SOC

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Posted 11 July 2009 - 02:23 PM

So pushing the wires in from the inside caused the connectors to click back in place and all is good. I am not a big fan of the crimp style lemo connectors for this very reason. Had the exact same thing happen to me once before with a cable. Of course I am sure those connectors are a whole lot easier to put together than the solder style.

I did run into another problem momentarily but I figured out the problem. If I moved the focus knob quickly one direction then back the other the motor would start twitching. I noticed that the status light on the receiver was also changing colors momentarily as I moved the motor and it turns out the power supply I was using was only rated for 2.5amps. Switched to a battery and the problem went away. Interestingly It was only happening with my right angle motor cable so I am guessing that it has slightly more resistance in it. With the battery I couldn't reproduce it with either cable.

~Jess
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#9 Eric Fletcher S.O.C.

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Posted 11 July 2009 - 05:55 PM

So pushing the wires in from the inside caused the connectors to click back in place and all is good. I am not a big fan of the crimp style lemo connectors for this very reason. Had the exact same thing happen to me once before with a cable. Of course I am sure those connectors are a whole lot easier to put together than the solder style



In 26 years of dealing with Lemo cables I have NEVER had the issue you describe with lemo connectors.
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#10 Jess Haas SOC

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Posted 11 July 2009 - 09:17 PM

Well in my 5 or so years of dealing with them I have had it happen twice. With the solder style connectors the pins are built into the connector itself and it can't really happen. With the crimp style the pins crimp onto the wire and are then inserted into the connector. They have prongs to keep them in place but sometimes for some reason they come loose and can be pushed back into the housing.

~Jess
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#11 Eric Fletcher S.O.C.

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Posted 11 July 2009 - 09:36 PM

Well in my 5 or so years of dealing with them I have had it happen twice. With the solder style connectors the pins are built into the connector itself and it can't really happen. With the crimp style the pins crimp onto the wire and are then inserted into the connector. They have prongs to keep them in place but sometimes for some reason they come loose and can be pushed back into the housing.



Jess,

I well aware of how Lemos are built, The only way that you can dislodge Crimp Pins (Actually a superior connection method compared to the solder pins) is to misalign the connector and force it
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#12 Jess Haas SOC

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Posted 11 July 2009 - 10:08 PM

I don't really disagree with you on that. In one case an AC was being kind of rought and a cable got pulled on causing one of the pins in the connector to be pulled out by the cable it was connected to. If it had been a solder connection I don't think the tug would have been strong enough to break anything but if it was stronger the case could be made that pulling out is a better outcome than the wire or solder joint breaking.

With the motor I am not sure how it happened. Since the connector is keyed and it is two of the 5 pins I don't really think misaligning and forcing it was the case but it could have been the result of bent or misaligned pins on the connector that was pluged in to it. I am not that rough on my equipment and my cables are in good shape but I did just recieve the motor back from being serviced where it is concievably possible that they plugged a cable into it that had bent or misalligned pins.

~Jess
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