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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

The SDI issues

Christoffer Glans said:
I still think that we need a native monitor from Red. Something we can use that doesn't rely on the SDI port. The biggest problem we have right now is that SDI is the ONLY way to monitor with any high quality.
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I think it's important to note that this isn't a RED specific issue, it's all current SDI cams. I just sent my Ursa G2 in because I somehow fried both my 12G and 3G ports within 2 weeks of each other. The 12G I figured might have been my fault but was playing it pretty safe with the second port after reading up on the issue. I'm just tempted to revert back to powering my monitor with Sony batts.
 
Tim Szczesniak said:
I think it's important to note that this isn't a RED specific issue, it's all current SDI cams. I just sent my Ursa G2 in because I somehow fried both my 12G and 3G ports within 2 weeks of each other. The 12G I figured might have been my fault but was playing it pretty safe with the second port after reading up on the issue. I'm just tempted to revert back to powering my monitor with Sony batts.
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Interesting to hear its happening on Blackmagic cameras. I wasn't sure if that was the case.
 
Nick Morrison said:
Interesting to hear its happening on Blackmagic cameras. I wasn't sure if that was the case.
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It's happening on all 12G cameras, for sure. Here's a review from B&H's listing of the Canon C300 mk iii:

After 2 shoots dead SDI, Canon repair didn't fix
By Christian 4/24/21
B&H Community Member

I've owned every C-series canon since the original C300, including the C100, C200, etc, and one of my favorite things has always been the robustness and reliability. However, after just 2 shoots on my newest C300iii both the HDMI and SDI died on the camera. I called Canon service - they said "yes that sounds like a burned out SDI card needs to be serviced" and instruct me to send it in. A few weeks later I get the camera back. They fixed one of the SDI ports. The other SDI still doesn't work and the HDMI still doesn't work. I called Canon service again. This time they didn't respond to my emails or messages. It's been a month and I've tried getting in touch to repair the persisting issue, but I've just been passed around by different "service people" and no one wants to listen or take the blame. B&H has also been no help. Even tho the camera is just a couple months old, I'm now stuck with a lemon. I spoke with another friend who owns the C300mkiii and his SDI ports also broke after minimal use. I suspect Canon has a bad batch of these going around and doesn't want to recall them. I do not recommend this camera.
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Tim Szczesniak said:
I think it's important to note that this isn't a RED specific issue, it's all current SDI cams. I just sent my Ursa G2 in because I somehow fried both my 12G and 3G ports within 2 weeks of each other. The 12G I figured might have been my fault but was playing it pretty safe with the second port after reading up on the issue. I'm just tempted to revert back to powering my monitor with Sony batts.
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It's a bit irrelevant actually. The fact is we have only one built-in SDI port and therefore we have these issues in this way. We had SDI ports on DSMC2, but they're on a module, easily replaceable compared to this. So it doesn't really matter that it's a known fact that SDIs are trouble. By choosing to go with this design, we ended up here.

So, I much prefer a solution than just accepting that the camera supposed to be a tank is built out of crystal glass. Red is in a position, not only to sell more gear towards Komodo users, but also to help out solving the risks we face. I cannot rent out this camera without a huge risk that the whole SDI-monitor setup gets busted. This is a problem and needs to be adressed in some way. Getting tired of Red's silence and seemingly lack of follow-up to things like these. Everything is at a stand-still for investment options and support only quote what's on the Red website guide about SDI procedures, without any further details or deep dives.

What's the point of this community if Red's ended any type of feedback on topics like these? As has been said before, by more people than me, it looks like Red shifted focused and abandoned this forum.
 
Nick Morrison said:
Interesting to hear its happening on Blackmagic cameras. I wasn't sure if that was the case.
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Without being a nerd and digging through forums I never would have known, it wasn't readily apparent. Used the camera for 2 solid years without knowing anything other than now where it's apparent *NOBODY* practices Safe SDI on set with P-Tap! $370 mistake and Ursaless for 2ish weeks. Should be back in time to flip and pay for my Komodo :)


As for what RED owes Komodo owners...I can't say. No one else has piped up about it even really being a thing, outside of 1 Arri paper...
 
Is it certain that the entire problem is this "power surge" described by ARRI and it is caused by improperly grounded SDI cables and/or DC current to ground from connection sequence? In checking the formal specifications for various cable connectors, it appears that for all other types of connectors (e.g. 3.1 USB, HDMI, DVI) there is a requirement for protection from ESD (electrostatic discharge ... the spark you see when you touch a grounded metal object on a cold dry day) ... In fact, Texas Instruments makes a series of "circuit protection ICs" used to protect circuits with these types of connectors. They are even incorporated into the SD cards we use. Curiously, they make no such device for SDI connection circuits (https://www.ti.com/interface/circuit-protection/esd-by-interface.html) and in checking their technical papers, there are technical hurdles to making them for SDI related to introducing parasitic currents that exceed certain specifications for SDI. If this is the problem (or a component of it) 12G SDI connection circuits are naked and there is no easy solution. The only choice will be to continue with the kluge solutions currently prescribed but it will help if you touch a grounded metal object before making power or SDI connections (that's why computer techs wear grounding straps). Cinegears specifies that their wireless transmitters do provide ESD protection but I have yet to receive and answer to a request for more details. Teradek does not list ESD protection in their specifications. RED, please comment.
 
BY the way, IF ESD is the PRIMARY problem, it would explain all the previously described phenomena, including issues with broken shields on SDI cables, p/d tap connectors, etc.
 
Kathryn Rohr said:
BY the way, IF ESD is the PRIMARY problem, it would explain all the previously described phenomena, including issues with broken shields on SDI cables, p/d tap connectors, etc.
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YUP!

One can lookup the design constraints for SDI. 3G operates at a low enough frequency("low" being a relative term) that the overall capacitance of the circuits are fairly easily protectable. 12G, on the other hand, operates at a very high frequency (4x 3G) . As a result, the capacitance of the circuitry, and the operating ON/OFF digital signal current must be so low that it becomes susceptible to damage from the ordinarily encountered inrush current when a battery is connected. The analogy is a garden hose where the spray nozzle is closed off. When one first opens the water supply valve, the hose pressurizes, even if there is very little water flow. The only flow is what's needed to stretch the hose. If there happens to be a weak spot in the hose, it will burst when the sudden pressure pulse exceeds the strength of the rubber, even if the hose didn't burst the last time it had an open nozzle. The ability of the rubber to stretch without bursting can be related to the capacitance of the circuit.

The real solution, here, may be to provide a buffer circuit that prevents that sudden pressure pulse of current. That's what a blocking capacitor is supposed to do, but, at 12G frequencies, the required protection capacitance is way too small. So, it needs to be protected by circuitry that buffers ALL current pulses. The side effect on operation would well be a lag in SDI signal.
 
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My biggest issue is rentals for Komodo. Once the camera is out of your hands - do we really expect a crew to memorize the power up/ down sequence for SDI and use only cables we provide? Never gonna happen. I rented out my Komodo and with all the SDI rules explained - the port came back fried. Not cool.
 
Now that I am sufficiently worried about frying my video board, how do I know if my SDI cables are shielded? Most of the ones on B&H don't say one way or the other. Ive been using the thin ones from SmallHD for a few months and haven't had any problems, but could just be flirting with disaster. Anybody have any recommendations on quality cables? Obviously won't fix the problem, but seems like the obvious place to start.
 
Kathryn Rohr said:
and in checking their technical papers, there are technical hurdles to making them for SDI related to introducing parasitic currents that exceed certain specifications for SDI. If this is the problem (or a component of it) 12G SDI connection circuits are naked and there is no easy solution. The only choice will be to continue with the kluge solutions currently prescribed but it will help if you touch a grounded metal object before making power or SDI connections (that's why computer techs wear grounding straps). Cinegears specifies that their wireless transmitters do provide ESD protection but I have yet to receive and answer to a request for more details. Teradek does not list ESD protection in their specifications.
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This is exactly the issue.

I'm guessing that anyone that says they offer ESD aren't supporting 12G connections. ESD protection and 12G are incompatible.

JB
 
Higher bandwidth connections are needed to support modern video signals. The BNC/Coax topology for SDI is reasonably reliable for 1.5 or 3G signals. Props to the engineers who figured out how to cram 12G through that pipe. Unfortunately, in the real world, the cables/connectors/ports are not always going to be perfect.

IMHO, the industry needs to move to a new standard that can, theoretically, handle 60G signals up to 50' without DAs. Early iterations may only be 12 or 24G, but the physical connectors and cabling should have enough headroom to support more as we move forward. As a reference, HDMI 2.0 is 18G and HDMI 2.1 is 48G - though currently available chipsets max out at 40G. ThunderBolt4 is a 40G topology, though overhead eats up a little of that in current implementations.

Both HDMI and TB4 use connectors that were not designed for the kind of abuse typical on set. A metal cladded version with a locking collar perhaps?

Ideally there would be a copper cabling solution, but I'd imagine optical fiber is the only viable choice. AFAIK, current optical fiber links require chips on both ends to encode and decode. Robust cabling - sometimes referred to as "tactical fiber" is available - but last time I looked it was rather expensive.

Cheers - #19
 
Cinegears reply

Cinegears reply

Kyle from Cinegears answered my question today. His reply concerning ESD protection on their wireless transmitters is as follows:

"Thank you for reaching out regarding our Ghost-Eye Wireless Transmitter and the ESD protection. This ESD protection provides both the devices and camera’s SDI and HDMI connection with ±8 kV ESD protection level (HBM, contact discharge). While I can not guarantee that this ESD protection is the solution to the burnt 12-G SDI boards Komodo users have been experiencing. I have sold several of these systems to Komodo users over the last several months and have had no issues reported to me. Additionally, I have a marketing partner that has been using our Ghost-Eye 800m systems along with Their Komodo who I regularly check in with and is extremely satisfied with this system."

On the other hand, the best I can determine from Teradek is a published warning "Bolt 4K devices contain sensitive electronic components that can be damaged by electrostatic discharge (ESD)."

So at least Cinegears recognizes the problem and attempts to provide a remedy. Obviously there is no guarantee that you can't fry your SDI board with Cinegears in your rig given all the permutations of connections we can create .... but at least they provide another layer of possible protection ....Guess whose wireless video transmitter is going to be the first device on the output of my Komodo? I have also changed all my power connections to LEMO and all cables are shielded. Obviously I will still follow the recommended connection sequence .... time will tell. About time the industry cleans up this problem and I certainly like the optical cable solutions suggested above. We have been using that technology in high bandwidth networks for years and it is definitely robust and the cost of implementation has dropped significantly.
 
Robert Hofmeyr said:
Oh dear. I've purchased one of those.
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Just reporting back on this. Received my Allen Avionics HD-VIT-75 Video Isolation Transformer from B&H and it seems to work fine. Hope it solves this issue - at least it will give me some peace of mind. I see people posting on FB with blown SDI ports all the time, many saying they always followed the recommended procedure. One guy says he has blown his port 3 times. This seems to be a very frequent issue, yet many owners are still not aware of it.

Mounting the isolator was more tricky than I expected: I thought it would be smaller. Couldn't find somewhere out of the way on the camera, so I ended up attaching it with velcro to the back of the monitor. This way I can easily move it if I need to.

00Gmgm9.jpg
 
Hey Robert,
This isolator should work fine with 1080P (3G-SDI), but, have you tried to output 4k (12G-SDI) with it?
 
There's not much to add. Using a fiber link between SDI terminals totally decouples any voltage or current transients, since it's an optical link. And, you get the additional advantage of up to 10,000 ft transmission distance without a repeater. Each module is a duplexed transmit/receive SDI to optical fiber converter. The sfp's are connectors between the fiber cable and the converters.
 
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