Sparks Through the HD-SDI line??

[Kyle Wullschleger]

The breakdown - I have a Steadyrig sled and electronics and the HD line was added in separately. The base has 3 Anton Bauer plates and you can switch the two rear into a separate or parallel mode for longer 12 Volt operator or switch it to 24 volt. I wasn't powering the Epic through the sled, but I had left the sled in 24 volt mode from the previous Alexa job while I was setting up. But, nothing was being powered from the sled except for the monitor which runs off the front battery and a d-tap to USB powering an SDI-HDMI converter.

 

So, I don't understand how this could have happened but while setting up my sled before a shoot, I had everything on board and when I went to connect the BNC cable from the camera to the top stage input for the HD line, it started to spark! I was shocked... not literally. So I started to troubleshoot where the power was coming from, deducing it wasn't from the camera, I moved to the bottom stage where I had the HD-SDI line going into an HDMI signal converter and into a Marshall monitor.

 

I removed the front battery, that powers the monitor - still sparks. I removed the accessory battery from underneath the sled - still sparks. Then I removed the battery in the camera power slot and the sparks stopped. So that battery was a fully charged AB Dionic 90. The other batteries were v-mount PAG Link batteries with AB-Vmount adapters... just out of curiosity knowing that Antons have a reputation for being 'overcharged' I connected one of the v-mounts to the camera power slot with the adapter, and sure enough no sparks.

 

The only damage was my signal converter fried and for the first time I was happy there was an HDMI option out of the camera and I had a cable in my case just in case the converter ever went on the fritz. So the shoot went on.

 

Anyone know what's going on here? I did flip the sled to 12 volts after realizing it was in 24 volt mode but this was after I had connected the v-mount to the top position without incident and again nothing was being powered through the sled. So I don't know if flipping the sled to 12 Volts with the Anton on there would have changed anything, and I didn't want to keep making sparks come out if I didn't have to by going back and testing it.

[Osvaldo Silvera SOC]

Contact Hugo about this at Steadyrig, and then contact the person who added the HD/SDI line on the sled afterwards. Have you had the sled for a while and used it in many configurations? did the sled get hit between jobs?

Carefully open up the base, and visually look around the video connectors so you can see if anything seems odd or out of the ordinary. Then Call the folks to talk about the issue, so your better prepared to describe anything you see in the wiring.. Something in the cmera plate wiring may be touching aluminum which could send power thru everything. Use a tester on the connector to see if there is any readable power coming thru there..

 

Just some thoughts!.....

[James Puli]

Terry West in LA is Hugo's guy in LA! I'd be bringin your rig out to Cinegear with you and get Terry to give it a once over!

 

That's totally strange man.... Never had that one!

 

Except on a different rig where one of the 12v power lines was touching the HD video line in the lower junction box! Didn't see sparks, but the monitor blew up and made that nice burning electronics smell!

 

JP

[Kyle Wullschleger]

Thanks for the response guys -

 

I've had the sled since January so I haven't used it in too many configurations, and I only just recently got the HDMI converter box and have used it successfully a hand full of times through the HD-SDI line - but I know the sled has been around a while, the junction box is serial #11. That said, no hard knocks since owning it and I just opened up the upper and lower junction boxes to take a peak and upon my own inspection nothing is loose or knocked out of place and there are no spots of bare wiring touching the HD line (or any other potential crossovers).

 

I don't have a meter to do any testing with right now to see what's what (shame on me, I know), but I will be picking one up.

 

James was the previous owner, so I'll get more specifics to the situation from him off board - for the record, James has been very helpful providing information and answering any questions I've had about the sled and I wouldn't say this had anything to do with his gear. I am headed out to LA for Cinegear anyway, so I'll drop Terry West a line. I'll be sure to report back on anything that might be worth reporting in case someone else ever comes across the same situation as I'm sure there are a few other converted HD sleds rolling around out there.

[John Ritter]

Hi Kyle

 

"just out of curiosity knowing that Antons have a reputation for being 'overcharged"

 

 

You can rule out the Battery being the culprit.

Reports of Anton Bauer overcharging are false since the charger and on board circuitry will limit max charge to 16.8 Volts.

All the Video Li-Ion battery packs will limit the max to this voltage or slightly less.

 

The discrepency of out put voltage will show up with older battery packs which usually will not charge as high as a new one so

that is what may be the case when you swapped packs. (also the use of the adapter plate can cause a slight voltage drop)

 

And if a lower voltage eliminated the sparking then you will have a very small hard to detect short or contact fault somewhere.

 

Unfortunately the only way to find the cause is to open things up and trace out all the wiring and connections as you have a short or back feed ocurring

(wire/contact/connection) somewhere in the system.

 

Regards John Ritter

www.ritterbattery.com

[Kyle Wullschleger]

Thanks for the information John -

 

If I do indeed have a short or back feed - would a continuity meter be able to confirm this by touching one end to the positive or negative connection of Anton receiver and touching the other to the HD output?

[Kyle Wullschleger]

Also, I spoke with Terry West over the phone, and he hypothesized the camera itself may be sending a charge through it's own chassis into the sled chassis just through contact. I can't test this too easily as the camera body, nor the culprit batteries are mine, but I am going to see about getting access to the kit once I've got a voltage meter and can see what's outputting what.

 

It still seems to me that if it stopped sending voltage out once I removed the specific battery that it probably isn't the camera, but Terry's point was the way they retro-fit the HD line in the Steadyrig sled, there really isn't another point of contact besides the chassis itself.

 

Regardless, I'll be keeping a voltage meter with my sled at all times and checking the HD line before I hook anything up in the future.

[John atkinson]

You created a ground loop by having separate battery sources. You can avoid this by making all connections before turning on breakers and/or camera. I had this happen once and it fried many boards in a video camera. Bad stuff!

[Kyle Wullschleger]

Ah! This makes sense. So Terry was right (duh) in that the camera itself was producing voltage and causing the ground loop. http://en.wikipedia.org/wiki/Ground_loop_%28electricity%29

 

I know in this instance the camera was powered on when my AC placed it on the sled.

 

The last connection I was making, and the one when it started to spark was when I took the bnc cable from the camera and placed it near the top HD connection. Which by systematically removing the batteries from the sled trying to figure out if it was a specific connection, I stopped the ground loop, the Dionic just happened to be the last battery I removed.

 

Thanks for chiming in John, I'll keep an eye on things to confirm this is what was happening, and I'll be sure to ask my AC's to keep the camera powered down when placing it on the sled in the future.

[Evrim KAYA]

Hello Kyle,

 

So if I understand correctly, the camera –powered on- leaked electricity through its BNC output. Then by connecting the hot BNC cable coming out of the camera to your sled, you inadvertently feed electricity to your sleds BNC input which in turn passed through your electronics –and fried them- and ended up in your battery’s ground.

 

If that is what happened, what difference would it make to turn the camera off before connecting the BNC? If there is a leak from within the camera, feeding power to the BNC, it still will burn your electronic when you turn it on. Will it not?

 

Also, if this is what happened, you shouldn’t have to pay for your repairs as the faulty camera –that you didn’t own- caused all this. Am I right?

 

Perhaps I misunderstood what happened. Could you confirm my train of thought so I could benefit from your misfortune?

[Kyle Wullschleger]

Evrim,

 

I don't have any background in this stuff, but if it was indeed a ground loop - from what Terry was postulating and John Atkinson filled in the holes by putting a name to it, essentially it wasn't a charge coming from the HDSDI out of the camera, but when powered the camera chassis can have a charge, and when you place it on the sled, it grounds to the sled.

 

The sled's electronics are already charged and I'm assuming grounded out to the chassis of the sled as well just by having the batteries connected, and in this instance, feeding power to my monitor and the signal converter.

 

So when the charge of the camera grounds to the sled, if its at a different potential energy, this causes the ground loop then in some circumstances this can cause an electric shock. I think had I touched the bnc connection to any of the outputs on the sled, that they all would have been charged, but I wasn't aware of this at the time so I can't be 100% sure this was the case.

 

In any regard, if I understand this correctly.... if you make all of your other connections first and the camera is already in the loop, when you turn it on, any voltage it may be outputting into the sled is a part of the circuit and not a separate source, so it's potential is the same?

 

This diagram from wikipedia shows two separate power sources, Voltage 1 and Voltage 2 meeting at the same ground and causes a different ground potential.

 

 

I suppose your question remains in the opposite form as well - if I just pulled off the batteries to rid the potential energy of any sled power, but put them right back on without incident, why wouldn't they cause a ground loop?

 

Anyone with more knowledge or a better understanding care to extrapolate this further and explain?

[John Ritter]

Thanks for the information John -

 

If I do indeed have a short or back feed - would a continuity meter be able to confirm this by touching one end to the positive or negative connection of Anton receiver and touching the other to the HD output?

 

A continuity tester and a volt meter will help tremendously, start by checking positive to ground (any of the metal i.e. camera, post, etc.) then check further downstream.

 

Kind of hard to guide you without seeing it or knowing the wiring.

 

From your description of the connection order I would guess the issue is with the camera negative to case (grounding) since your rig has never done this before with another set up.

 

Could possibly be in the camera battery plate....... Since the camera is not yours it is very possible something came loose during transport/handling.

 

I would check the camera & battery plate before going into your rigs systems.

 

Regards John Ritter 954-557-9765

www.ritterbattery.com

[Evrim KAYA]

but when powered the camera chassis can have a charge, and when you place it on the sled, it grounds to the sled.

 

 

The camera isn't suppose to have a charge on its chassis. This is a camera problem which in turn fried your sled's electronics. As much as i would like to know exactly what happened in order to prevent such a thing ever happening to anyone of us, i think your sled is not responsible.

[Kyle Wullschleger]

Good point, Evrim - and to be sure, the electronics in my sled are not fried and everything still functions after the incident, just the signal converter seemed to go, and luckily it was a really cheap SDI-HDMI converter - http://bit.ly/YWye4M

 

Thanks for the advice John, I should have a chance to run by a hardware store tomorrow and run through the connections on my sled just to be 100% sure. I've contacted the Epic owner and after a conversation with him tonight, he said he doesn't have the camera in his possession currently, but he will report back to me as soon as he does.

 

John Atkinson - do you know why turning the camera on once everything else is connected, or disconnecting batteries then attaching them last keeps ground looping from happening?

 

..... Just when I was starting to think electricity wasn't that complicated.

[Phil Moreton]

Good point, Evrim - and to be sure, the electronics in my sled are not fried and everything still functions after the incident, just the signal converter seemed to go, and luckily it was a really cheap SDI-HDMI converter - http://bit.ly/YWye4M

 

Thanks for the advice John, I should have a chance to run by a hardware store tomorrow and run through the connections on my sled just to be 100% sure. I've contacted the Epic owner and after a conversation with him tonight, he said he doesn't have the camera in his possession currently, but he will report back to me as soon as he does.

 

John Atkinson - do you know why turning the camera on once everything else is connected, or disconnecting batteries then attaching them last keeps ground looping from happening?

 

..... Just when I was starting to think electricity wasn't that complicated.

 

 

Hi Kyle,

 

Did you get any update from the Red Epic owner about this?

 

I'm having a similar problem at the moment, but I think it is related to the Red Epic v-mount plate.

 

I have my V-mount plate attached to my camera. It powers the camera fine via the cable attached into the v-lock plate.

I then attached a d-tap cable to my v-mount plate and then to my monitor a spark occurs. Camera turns off.

I try the monitor through another battery with the same cable and it is fine.

I try the monitor through the battery when it is connected to the camera and it sparks.

Is the v-mount battery plate causing this problem. As the d-tap ports on the plate do not work now.

 

Update:

As an update it only happens when I have the HD-SDI cable plugged into camera and monitor.

It won't spark if the HD-SDI cable is not attached.

Happens on both my Epic and Scarlet cameras with same plate. So it can't be a fault with both HD-SDI ports or shorting from inside the camera.

Problem does not occur when I power monitor separately and camera separately.

 

Thoughts?

Is the plate causing this problem.