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Power Tap Issues?

Mitch Martinez

Mitch Martinez

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I was on a shoot where my camera was used for a three day short film gig. A Bartech Wireless Follow Focus was rented from Du-All Camera for the AC and the follow instances occurred:

Day 1 - First half of the day was all on Steadicam where the op had his own RED v-mount battery plate on his counterweight section of the steadi rig. Power for the RED and Bartech pulled from my batteries on his rig. No problems

Second half of the day - after about an hour, I was notified that the camera was simply shutting off even though there was plenty of charge on the batteries. No warning. Simply cuts to black and the power is gone. We pulled my battery belt clip and tried powering from that since the Bartech was still requiring battery power (or else we would have simply gone with AC power from the wall). This worked and finished out the day



Day 2 - Since the belt clip battery plate finished the prior day, I swapped it onto my standard RED Cradle and had it ready to go for Day 2. First half of the day was Steadicam again and power was again pulled from the steadi rig without problem. Dolly, handheld and sticks shots followed with the RED cradle with the 2nd battery plate from Day 1 - no problem.

The last set up of the day was an exterior jib shot. We were setting up the camera when there was a "pop" inside the Bartech motor box and smoke started pouring out of it. The RED camera seemed to be fine and we switched up to a manual follow focus for the rest of the shoot.

Day 3 - All follow focus was done with my manual Arri MFF and no power issues presented themselves.



So I'm not a technician in any way for this sort of issue... Any thoughts on what happened? I checked for similar threads but didn't find anything that matched. Since we swapped out two different battery plates, I doubt it's an issue with both of my battery plates. On the shoot, we had four different RED batteries in steady rotation (all purchased at the same time).

Does RED have any established power tap issues? Is it possible there was a fault in their power tap wires even though there was never a problem when they tapped power with the steadi rig? What should I do in the future for wireless follow focus units to make sure this sort of situation doesn't happen again?

Looking forward to your feedback. Cheers!
 
Bartech has issues on a Red...I find if you calibrate the lens with the camera off, then turn the camera on, it will run fine. But if you try calibrating while the Red is turned on it will shut the Red down.
 
Never had those issues.

For instance We are curretly running off the v lock plate and ptap:
R1
Preston with all 3 channels.
Cinetape
Hd wireless system.

I have often had a down converter in the mix, but not on this gig.

I have also used bartecs plenty of times off the ptap with out needing to do anything out of the ordinary.

I will say I throughly vet battery plates and always bring extras.
 
Mitch Martinez said:
The last set up of the day was an exterior jib shot. We were setting up the camera when there was a "pop" inside the Bartech motor box and smoke started pouring out of it. The RED camera seemed to be fine and we switched up to a manual follow focus for the rest of the shoot.
Click to expand...
Sounds like ESD damage, electrical short or perhaps the pop was most likely a capacitor at the end of its life.
 
They were not using a run start stop cable so camera does not matter. Usually reverse polarity will do this and the bartech has a 2 pin Lemo for power. Can be pushed into the mating connector upside down.
 
It's always the AC's fault. That happened to my unit last week. And I saw the connectors totally plugged in the wrong way. the Bartech is battle tested and it never fails. And even though is idiot proof. There's always a "brilliant AC" trying to do it all wrong.
 
Okay. Thanks for the info everyone. So to confirm what people are saying, it sounds like the reason the camera might have been shutting down is because of calibration with with Bartech unit while the camera is on? And the reason the unit might have blown was due to reversed polarity on the two pin Lemo cable?

Is there any chance this would have messed anything up with my RED camera or my batteries? I've shot since with it and everything seems fine but I never want to assume...

Thanks again for all your feedback
 
It's also possible to plug in a P-Tap connector upside down if force is used. Also there were anecdotal accounts in the past that the Red battery plate P-Tap connector profile allowed reverse plugging rather easier than some other makes like Sony or IDX. I always double check when plugging P-Taps of whatever brand.
 
were you powering the Bartech from the 2 pin lemo or D-tap?

Never power the bartech from the 2 pin lemo, it draws too much power.

Regarding the d-tap, it is my experience that lens calibration causes a power surge that shuts the Red down, I simply avoid calibrating lenses with the Red on, which is a pain.

Your problem is very different from mine and indicates operator error. I would assume someone inverted the power...Ive never seen one smoke.
 
Greg M said:
were you powering the Bartech from the 2 pin lemo or D-tap?
Click to expand...

I'm not 100% sure. Since I wasn't on camera - simply supplying it, I observed what they were doing with my RED from a distance. My memory is a little fuzzy. I just remember it was Bartech.

Steve at DuAll who replied to this thread earlier might actually know since that's where it was rented.
 
In general it is much easier to insert a P-Tap reversed that it is to insert the Lemo reversed unless the Lemo is extremely worn or damaged. The shutting down of the camera during calibration is much more common with the RED batteries than with Anton/Bauer or IDX because they cannot source as much current.

Jim Bartell
 
Mitch Martinez said:
I'm not 100% sure. Since I wasn't on camera - simply supplying it, I observed what they were doing with my RED from a distance. My memory is a little fuzzy. I just remember it was Bartech.

Steve at DuAll who replied to this thread earlier might actually know since that's where it was rented.
Click to expand...

We only supplied a Dtap cable that plugs into the 2-pin Lemo power on the Bartech receiver and not the GPIO port on the RED which I believe is a 4 pin? Don't have the camera in front of me now. Anyways I did not know about the Red bricks not supplying enough power since I don't use them.
 
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