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Electric issues with the Arri WFU3/UMC3a and d-tap?

Gunleik Groven

Gunleik Groven

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Hi.

We have two kits out with said Arri remote FF kits.
With two 2 motors each.

One works like a charm off the D-tap.

The other regularily shuts down the camera when you start the motors.

Does this ring a bell anywhere?


Cheers!
Gunleik
 
power issues.

power issues.

my guess is that the battery is border line and since the ?Alexa is such a power hog the motors load the battery enough to drop the voltage below camera treshold consequently causing shutdown.
It's certainly not anything I've heard of before...
Certainly easy enough to verify- take voltage reading during motor initiation.....
 
It's on two different R1 MXs... No Alexas were used to harm these shoots...

They are a bit apart in their serial #, though...

Thanks
 
BTW. The setups are identical as to electrical equipment, with the same batteries used (GlobalMediaPro RED-type 190WH and RED Bricks).

Both recording to drives.

LCD + EVF

Both recording both in studio and outdoors (today that means -10 centigrades).

Anyone know how much current the EVF eats?

Cheers

G
 
have you cross tested the two units, i mean connecting the "bad" umc3a to the other red and vice versa?

best wishes,
martin
 
Gunleik,
Have you tried using an alternate power source on the camera, and simply wearing your V-mount battery to power the wireless?
The MX is every bit the power hog as an Alexa, and I think Jacek is barking up the right tree. The P-Tap is "dumb" power, so I would think it would only shut down the camera by virtue of killing the battery.
Try running the camera off a block battery, or the power supply (if you're on a remote head) or the Steadicam sled (if you are on a Steadicam)
Lots of times I will run my Reds (and Alexa) from my Lentequip blocks and wear an Anton Bauer to power odds and ends on the camera.
Cheers,
Harry
 
Thanks Harry!

This is what we suspect.

After digging a bit, it seems like the production without issues is mostly NOT using the EVF, and never both EVF and LCD.

Unfortunately I cannot A/B swap the equipment, as they are both on quite busy and long shoots + additionally not being in the neighbourhood of eachother.

It did solve the issue today to give the Arri it's own battery.

Where we're shooting, AC is not an option. And we don't have those juicy block batteries for the MX.

I know about the similarities in power-usage of the two mentioned cams in similar setups, though...
 
Yeah, it sounds as if the combo of both EVF and LCD may be just enough to over-amp the setup.
Keep us posted once the gear gets back, if you can ever find out definitively what combo is too much.
Cheers,
Harry
 
On MX we find there is very little power to spare - if you have LCD + EVF and then on top of that want to run something else it will often put the camera below AMP threshold and it will simply shut down like it would from a dead battery.
 
We had problems with older versions of them because they are built for 24v. I dont remember exactly the version which is built for 12v....
 
We have the 12V version.

What has solved the issue, is to feed the FF from a separate battery.
Fun thing, though - is that the FF almost doesn't use any electricity over a day, but apparently takes a chunk just when the engines start up.

Cheers!

G
 
Rob Ruffo said:
On MX we find there is very little power to spare - if you have LCD + EVF and then on top of that want to run something else it will often put the camera below AMP threshold and it will simply shut down like it would from a dead battery.
Click to expand...

Sounds like what we're seeing...
 
Hello,
sometimes the problem causes from the batteryplatte and the d-tap, some are only designed with a 50W output and less then 8 amp, which will not be enough to circel on the camera (especially if you would have lots of other stuff hanging on your red e.g. transmitter, downconverter, evf heater :))

best
feyco
 
Thanks Feyco

On the GlobalMediaPro batteries there is a D-tap directly on the battery, as an alternative to the batteryplate D-tap.

Results are the same, though.
 
Hello Gunleik,
i just looked on a website to see which battery-typ you were taking about and noticed that we were using the li160s for our assistant-monitor.

i will try to do some test on monday, with this battery as the main battery for the red with all its stuff on it, just to see if i get the same result, cause we were also shooting with the arri wlcs.

But it seems to me that this battery is just to weak, especially if you said that it works when puting the wlcs to a seperate battery.

You can also try to splitt some of the extra stuff e.g. putting the downconverter and the transmitter to the battery d-tap and the other ones to the batteryplate d-tap.

best
feyco
 
Thanks. We're using RED Bricks (140 WH) and GlobalMediaPro "RED edition" (190 WH).

Fun thing is that the same exact setup is working on one production, but not on the other... (the exception being that one rarely uses both LCD and EVF at once, which probably is what is causing this)

What makes me think that something may be wrong with the FF motors, is that they in themself almost do not use electricity over the day, but it looks llike the startup current needs to be rather strong...
 
i see, just forgot that you mentioned that you were using the exact same setup at a secound production.

well, its the more easy way to change some ff motor instead of the complete batterypackage, if this problem will be gone, you would be absolutly right with your guess that the motors maybe damaged.

and if the problem is still there, it may be the batterys who can't handle the evf/lcd combination with the attached accessories, which you can test by using some really heavy battery like a bluechape bv190hd, but be sure that the batteryplate is 70w output while using the bluechape otherwise it may get some problems, too (we have had at another shooting)

best feyco
 
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