SDI burnout/rolling noise issue BMCC 2.5k EF

Thanks Mubarak.
I had a quick look at the post at that link.
I also had a closer look at the photos posted above.

Although the photo of the PCB was small and blurry, and it would have been helpful to see both sides of the board, it looks like a basic DC-DC convertor/regulator for each of the plate's barrel type power connectors, and each connector looks like independent floating negatives (or grounds FAIAP). I can't tell 100% for certain without seeing better photographs or handling one of them in person.

The D-Tap connector is connected directly to the battery terminals, so it will also have a different negative potential than the rest of the barrel power connectors.

The floating grounds will be for safety reasons and to allow for isolation between devices powered by the plate, however, that means that there will be a chance of problems caused by voltage potential drift if two devices are connected to individual power connectors AND also have an additional cable between them.
For example, with an EVF setup, where the camera is on one plate power connector, the EVF is on a second plate power connector, and an SDI cable is connected between the devices.
You should also be able to read random voltage differences between the device's SDI connector shells when the connecting SDI cable is removed.

I'm willing to bet that this issue isn't just a BMC plus Tilta plate issue.
That plate design when also used on any other camera, such as a Canon C100, C300, etc., along with an EVF connected to a second voltage power connection on the plate, is going to have the same frying problem.

If I had one of these plates, other than making some serious modifications to it or throwing it away, I would only use it with a camera and EVF setup if both the camera and the EVF were powered from the exact same plate power connector.
For example, plugging a D-Tap multi-tap into the plate D-Tap connector, then D-Tap cables from the multi-tap over to the camera and EVF. That way they are using a common negative connection, with no chance for floating voltage potential variations.

When used on a setup such as the plate's D-Tap to the BMC and one of the other plate power connectors to a mic preamp, there probably won't be any issues since the BMC uses isolated ground connections on the 1/4" TRS connectors.
Although, IMHO any voltage potential swings will still be hard on the equipment components, and I wouldn't do it.

IMHO, anyone who is using this plate, or any plate that is using the same design of independent floating negatives, should never connect any two devices to two different plate power connectors when there is also an additional cable between the devices.
If a device is going to be cabled to any of the camera's inputs or outputs, then that device should also be ran from the same plate power connector as the camera.

According to your findings Is it safe to conect a viewfinder indenpendently (not from the same power source as the camera )?

Sent from my GT-I9070 using Tapatalk HD

Is it safe to conect a viewfinder indenpendently (not from the same power source as the camera )?

That would be difficult to answer without knowing detailed circuit design of the two devices.

In the case of a camera and an EVF, where each are connected to independent power supplies, and an SDI (or other) cable is also connected between the devices. Note: this is essentially what the plate is doing with its independent power supplies.

Assuming that the SDI connector's shell/shield is also internally connected directly to the power negative on each device (the "chassis ground" if you will), then the circuit design will be utilizing the SDI cable shield to provide the common ground connection between the two power supplies.

If either device (the camera or the EVF) do not have their SDI shell/shield connected directly to chassis ground, or if the SDI cable length is sufficiently long, or if the SDI cable is using cheap higher resistance wire in its shield, I would expect a possible voltage potential difference measured from one supply's ground to across the length of the cable, even if only a few millivolts.

Whether this is detrimental to either or both devices would depend on their SDI circuitry design.

Disclaimer: I am in no way suggesting that anyone disassemble their equipment and start modifying it.

If you are asking would I run two devices mounted on my rig from separate batteries and rely on an interconnect cable such as the SDI to provide the common ground?

No, I wouldn't. Or at the minimum, I would make sure both devices were powered off and the batteries were removed prior to connecting or disconnecting the SDI cable. I would not connect or disconnect the SDI cable while either/both units are powered on or the batteries were installed. I would also purchase a reputable high-quality SDI cable.

Preferably, I would make sure both batteries were mounted on a plate that had a common negative (ground) connection, or I would add a proper ~16ga wire connecting their negative terminals together, so that they had a proper common ground connection. I would not rely on the SDI cable or any other interconnect cable to provide that common ground between the devices.

If I had a Tilta plate on my rig, I would disassemble it (and after verifying the issue up close!) and run a ~16ga black wire from the plate's negative battery terminal to the barrel connector shield terminal on the second supply that connected to the EVF, to create a common ground.

FYI, I did a quick google. There are numerous reports on other forums that Canon cameras such as the C300 and Sony cameras such as the F5/F55 are having the same fried SDI issues when using EVFs and battery plates.

I just want to say thank you David, for your information. You are probably the only person I know of, on many forums to thing about this from an electrical perspective, and have been super helpful. My eyes were nearly bleeding from reading 100s of posts that just listed the equipment people used and the situation that they sort of remembered.

Thanks very much, David! This has been a dark and mistirious trouble some people were having for some time nnow and without any real clue on what could it be.

Let me ask you one thing as I'm not a bit good on eletronics and might got it wrong.

So the problem is using a battery plate which has no commom ground? I ask because I was thinking about buying one (and just gave up), but I use my switronix to power my BMCC and use a 19' external monitor running through a sdi-hdmi adapter, which is sometimes powered from the wall outlet and sometimes from a sealed 12v 7ah battery. Does this apply to this case or only with a battery plate?

Thanks, man. Sure you're helping a lot of folks that you see and a lot which only reads this silently.

I have the same Tilta battery mount. I only use the D-tap as my camera plus directly into my battery and my EVF connects to the D-tap port on the board.

The back of the circuit board is black. It's covered with some sort of vinyl decal. Does not have any resistors on the back. Here is a better pic of the front.

https://www.dropbox.com/s/4sdojl83hkhi1 ... 1.jpg?dl=0
https://www.dropbox.com/s/hg5vvvja078ng ... 2.jpg?dl=0

Thanks David for the great Info.

Adam, I was thinking about doing the same thing after I read David's post. but isn't the D-tap 14 volts?

Im using the lilliput 663 monitor, and it needs 12 volts. I know it would work with the 14 Volts, But I thought I might risk burning out the SDI. So it didnt make sense to avoid burning SDI by doing something that might cause the same thing.

On all camera setups I would simply make sure that all devices are completely turned off before making any connections to any of the device's inputs or outputs, and any batteries that can be, are removed or disconnected since some battery outlets are always on.

Any cabling changes while the equipment is on and live may cause unforeseen issues. If the devices are powered on when cables are being connected, contact bounce when connecting the SDI cable may cause all manner of transient voltage spikes to go through the equipment and the SDI circuits.

The BMCC has an internal battery so that cannot be disconnected.

So the problem is using a battery plate which has no commom ground? I ask because I was thinking about buying one (and just gave up), but I use my switronix to power my BMCC and use a 19' external monitor running through a sdi-hdmi adapter, which is sometimes powered from the wall outlet and sometimes from a sealed 12v 7ah battery. Does this apply to this case or only with a battery plate

Assuming that on both devices the SDI connector shield is connected to the device's chassis ground.
One issue when using multiple power sources will be a likely voltage potential difference from one device's battery negative to the other end of any interconnecting cable.
The shield in the SDI cable will act as a low-value resistor, and a specific amount of current will flow through the cable shield between the two devices.
In this type of setup, IMHO it would be much safer if a proper large wire were connected between both of the device's battery negative terminals. Or a large wire connected between the two device's chassis grounds. I would still turn the power off before making cable changes.

In the case of running one device from the mains (building AC) with that device also connected to a battery-powered camera, chances are there is no easy access to the DC power adapter connections, so I would simply follow the above procedure of making sure everything was off and disconnected from power before making any cable connections between devices.

For anyone using AC power for their devices on outdoor shoots or in large building shoots, a proper GFCI equipped Power Stringer is always a good investment, and should be available at any store that sells Audio/Video and PA equipment etc.

I have the same Tilta battery mount.

Thanks for the photos Adam.

Unfortunately, the best I could do is to hazard a guess without seeing both sides of the circuit board up closer.
I will see if I can locate a Tilta plate from somewhere to get a better look at it.

Assuming that the camera is connected to the Tilta D-tap and the EVF is connected to the Tilta 12V tap.
If the EVF being used also has its SDI shield connected to the EVF's power negative, then connecting the SDI cable between the EVF and Camera is also effectively connecting the Tilta's D-tap negative to the Tilta's 12V tap negative.
This setup will be using the SDI cable shield to provide a connection between the two tap negatives, and if the devices are on while the cable is being connected, could have a negative effect on the SDI circuitry during contact bounce.
I would rather see a proper permanent ~16 gauge wire from the Tilta D-tap negative terminal to the Tilta 12V tab negative terminal. However, even in this case having the power off during cable changes would still be the prudent choice.

I would be interested to know if the majority of people who have fried their SDI, had it occur when they were connecting the SDI cable with the unit(s) powered on.

but isn't the D-tap 14 volts?

The Tilta D-tap connector is connected directly to the V-mount battery terminals.
So at any time the voltage there will be whatever the current charge level of the battery is.

The regulated 12V tap output on the plate will provide closer to actual 12 volts, but as the battery discharges, the on-board 12V regulator will draw more current from the battery in an attempt to maintain the voltage.

Most gear will usually run on around 10 to 14 volts.

I have just measured mine setup, and the SDI leak voltage was 0.02, just like I expected - I am burn problem free

I am using a standard battery plate, without any regulations. Just a power to the camera. Btw, the battery plate outputs 15v.

David Green I will personally mail you my Tilta plate to study further if you're interested.

I would like to get to the bottom of this. I just power my AC7, (which is new) and camera separately from now on. Camera is powerd by a single iKan v mount just to the camera and the AC7 with Canon LP-E6 batteries.

I had bought mine on ebay and I'm sure it was the real deal. I never wrote the company about replacing my past 2 monitors or 4 cameras.

I see people only talking about tilta plates...but this has happened on various other plates. Switchronix...Lanparte...Woodlan...Ikan to name a few. Ive seen it happen to people with sdi (straight) and hdmi (through converters). So not sure why the tilta plate is being singled out as the culprit.

I see people only talking about tilta plates...but this has happened on various other plates. Switchronix...Lanparte...Woodlan...Ikan to name a few. Ive seen it happen to people with sdi (straight) and hdmi (through converters). So not sure why the tilta plate is being singled out as the culprit.

Anyway you can post those mentioning plates other than the tilta? I've never read about other battery plates causing this issue.

I see people only talking about tilta plates...but this has happened on various other plates. Switchronix...Lanparte...Woodlan...Ikan to name a few. Ive seen it happen to people with sdi (straight) and hdmi (through converters). So not sure why the tilta plate is being singled out as the culprit.

Anyway you can post those mentioning plates other than the tilta? I've never read about other battery plates causing this issue.

I agree with Darren, There are many other people using different battery plates and had the same problem. Some even claimed they were not using an external battery when it happened.

Anyway, I literally just opened a page about the same Topic on the other forum and I found two plates other than the Tilta

Wondlan V-lock plate
Switronix v mount plate

So if some had experienced an SDI burnout without a battery doesn't that eliminate external plates all together? I think it's just a flaw in the camera.

So if some had experienced an SDI burnout without a battery doesn't that eliminate external plates all together? I think it's just a flaw in the camera.

Well, it might be a flaw in the camera. but most of the people who had the issue were using an external battery, and one or two people didnt use an external battery, I think its more likely the external battery. Besides, maybe the people who claimed they didnt use an external battery were using the AC power adapter, no one knows what exactly happened

Damn. I bought my BMCC used and finally got around using the SDI port but nothing worked. The convertor show it is receiving a signal (small blue light) but still no output. I connected directly SDI to SDI and nothing. I checked the monitor and it is working via my PC. Yes I have a Tilts power plate. I tried all power from the plate and then from the ac outlet. My situation is that it may have been blown before I bought it....

David Green I will personally mail you my Tilta plate to study further if you're interested.

My apologies, I missed your post before.
I plan on looking into this issue again in a week or two (end of Oct). If the offer still stands I can send you a PM at that time if I require a Tilta for testing, which will depend on what I find with the parts I already have. I promise not to damage it and will ship it back after.

I see people only talking about tilta plates...but this has happened on various other plates.

It is possibly an "I plugged it in with the power on" issue and/or an issue with having separate power supplies with no common ground.
I am going to spend some more time looking into it, since I don't want the same thing to happen to me.
FYI I have the Redrock Micro microPowerPod V-Mount Battery Plate on my rig.

David, maybe it would a good idea to contact a manufacturer like Viewfactor for some extra advice. They have created a battery plate (which I own one), so they should know the ins and outs.

Thanks Robert.

I actually don't think that it is intrinsically a battery plate issue for a few reasons including: This same damaged SDI issue is occurring with a few other camera brands; It is not occurring with other hardware such as on-camera audio devices (which will be using buffered interfaces).

I haven't looked into the actual circuitry used for the SDI interface, which is one thing I plan to do.
If it is not a well-buffered interface, then it will be susceptible to damage if either the camera or the SDI device are powered during cabling, and also from ESD.

I spent a bit of time today looking into this.

A few notes on the SDI interface.
Please note that this post contains personal opinion and is not meant to reflect positively or negatively on any third-party persons or manufacturers.

I will assume that BMD is using standard off-the-shelf components in their camera electronics as I have not seen any of their schematics. Since I have not seen any of the schematics, and I don't wish to disassemble my camera, I do not know which specific component part numbers they are using.

Some SDI Technical Information:

The SDI output interface uses a cable driver integrated circuit to drive a 75ohm coax cable.
This is a high-speed CMOS/BiCMOS IC implementing an open-collector buffer output.
A minimal output matching / back termination circuit is typically employed, with capacitor coupling to the BNC connector pin.
The BNC connector shell/shield can be connected to the device ground/chassis, however, many high end SDI implementations use a floating shell with additional ESD protection between the BNC shell and device chassis. And other hearty designs employ additional ESD protection on both the signal output and the BNC shell.

The SDI cable driver ICs are available from a number of semiconductor manufacturers including Texas Instruments (eg part # LMH0302 etc), Gennum (eg part # GS6080 etc), National Semiconductor, etc.

The commercial specification version of the SDI cable driver ICs only implement minimal ESD protection of ±2kV HBM (IEC 1000-4-2 level 1) on the I/O pins.
Integrated circuit pins used for I/O ports should have at least ±15kV of ESD protection (IEC 1000-4-2 level 4).
IMHO SDI cable driver ICs should have additional external ESD protection implemented by the product designer, or large warnings in the product owner's manual.

My Opinion FWIW:

After looking at the cable buffer design, IMHO SDI interfaces should never be hot-plugged.
It is not a question of if it will damage the SDI input or output buffer circuit, but when.
If you are connecting or disconnecting your SDI cable with either or both devices powered on, you stand a good chance of frying one or both SDI ports.

The SDI ports are also quite sensitive to ESD (electrostatic discharge). So static safety precautions should be implemented when connecting or removing cables.

I also had a look at a few of the manuals for the SDI equipment from other commercial and industrial manufacturers, and they have large red warnings in their owner's manuals to never hot-plug the SDI connectors.
The BMCC and other BMD SDI devices don't have this warning in any of their manuals that I could find.
All of this would apply to EVF's with SDI ports as well.

Think my SDI has burnt out on my BMCC

So what's the safest way to run an external monitor on a BMCC? A TVlogic 5.6 for example?

I have:
A Tilta Vlock plate
14.8v Vlock batteries which have a built in D-tap
D-tap breakout 4 x way box
Sony L series battery plate as an option to power tvlogic.

With my workflow I can't really rely on powering down both the camera and monitor before connecting the SDI cable option. I'd need a robust solution.

Thanks in advance
Jon

Think my SDI has burnt out on my BMCC

Sorry to hear that.
I hope the repair goes well.

So what's the safest way to run an external monitor on a BMCC? A TVlogic 5.6 for example?

The way I am doing it is I have an EVF with SDI In/Out mounted to the BMCC cage.
I leave the EVF connected all of the time using a short flexible SDI cable.
When I want to connect an external monitor, such as the Marshall I have, I connect that to the EVF's SDI Out. That way if I do something like forget that I have everything powered on (which I actually never do), I am more likely to damage the cheaper EVF.

The other option would be to use some small SDI block as a buffer between the camera and monitor, such as an SDI splitter (IndiPro etc.) or video converter (SDI In -> SDI+HDMI Out etc).
Always leave the SDI block connected to the camera, and plug/unplug the cable from the SDI block's SDI Out connector.
This may give some propagation delay, but it should be minimal.

With my workflow I can't really rely on powering down both the camera and monitor before connecting the SDI cable option. I'd need a robust solution.

I would really recommend changing your workflow.
It isn't a matter of if you will fry the SDI interfaces, but when.
You may be offline for repairs often.

Thanks for your reply David. Is this a fault with the BMCC camera? I'm actually shocked its so easy to blow the SDI port.

So powering wise, would one of these options be more robust than another? or is it all down to the SDI being unplugged while the devices are turned on?

1) Tvlogic monitor powered by Sony L battery, BMCC powered by dtap from Tilta plate.
2) D-tap splitter block from tilta plate powering both TVlogic monitor and BMCC.
3) D-tap splitter block from vlock battery powering both TVlogic monitor and BMCC.
4)D-tap from tilta plate powering TVlogic monitor, d-tap from vlock battery powering BMCC.

Thanks
Jon

Thanks for your reply David.

You are welcome.

Is this a fault with the BMCC camera?

The design issue is not Blackmagic's fault. All SDI interfaces are the same. Blackmagic is simply following the industry spec and using standard components.
The fault lies with the group who ratified the SDI specification (SMPTE afaik). See my above blurb on ESD.
If you check out the forums for other brands of cameras and gear, you will see the same issue of blown out ports.
If you check out most large rack-mount SDI interfaces, you will see large red warning stickers on them informing you to never hot-plug them.

I'm actually shocked its so easy to blow the SDI port.

The design group released an internal interface specification for an external port.
So it is completely a roll of the dice if/when it will get blown.
One person may be lucky and hot-plug 1000 times, the next may fry it immediately.
If you simply can't get into the habit of turning off the devices before cabling, be sure to ground yourself by touching the metal case of the camera first (in case you are carrying a static charge), use high-quality SDI cables that are kept clean and maintained, and be careful.
Adding an SDI splitter or similar device for a few hundred dollars, and always using it as the hot-plug connection is probably the best way to save the more expensive camera.

or is it all down to the SDI being unplugged while the devices are turned on?

This.
Static electricity and/or connector contact bounce while hot-plugging are most likely the main killers.

Thanks David,

I actually think it's ludicrous a professional product can break so easily!! Is there no way camera manufacturers can fix such an issue?

I've never heard of SDI ports being burnt on the Alexa, Red's, Sony f5, f55 etc

Just wondering, if its such a problem how come there isn't anything in the manual about how easily the port can be burnt out?

Thanks David

You are welcome.

Is there no way camera manufacturers can fix such an issue?

Two ways: 1) pressure on SMTE to ratify a new SDI standard that includes +/-15kV ESD or higher; or 2) integrate an SDI interface ESD protection IC such as from TI between the standard SDI buffer and the camera ports at additional cost or a possible decrease in slew rate (which may cause compatibility issues with some other SDI devices).

I've never heard of SDI ports being burnt on the Alexa, Red's, Sony f5, f55 etc

Do a quick google/yahoo search for any set of keywords such as "sony f5 sdi dead" or any other SDI equipped product and you will get returned results from other user forums with people who are experiencing the same issue on all other hardware.

Just wondering, if its such a problem how come there isn't anything in the manual about how easily the port can be burnt out?

I have mentioned a couple of times that Blackmagic should put a disclaimer/notice in the product manuals regarding this. Why they don't is beyond me.
Numerous high-end pro rack-mount SDI distribution and splitter/re-clocker units that I have seen include large red labels on the unit and big warnings in their manuals regarding never hot-plugging.

SDI is similar to plugging internal SATA hard drives into your computer directly at the motherboard.
Both interfaces have similar ESD specifications = internal port level of ESD only.
You don't typically let people willy-nilly hot-plug SATA drives direct into the motherboard.
Typically a backplane or eSATA interface is used which has an external rated ESD protection specification.

*edit for minor typo*

Two ways: 1) pressure on SMTE to ratify a new SDI standard that includes +/-15kV ESD or higher; or 2) integrate an SDI interface EMF protection IC such as from TI between the standard SDI buffer and the camera ports at additional cost or a possible decrease in slew rate (which may cause compatibility issues with some other SDI devices).

It's my understand this would severely limit the cable length runs possible with SDI, which is one of the (current) main benefits of SDI?

It's my understand this would severely limit the cable length runs possible with SDI, which is one of the (current) main benefits of SDI?

That is correct.

A circuit's ESD protection can be increased for example by a slight modification of the output design, typically adding a small value capacitor. Additional circuitry can raise the ESD protection even higher. But doing this can affect the slew rate (the signal change time).

As the slew rate decreases, in order to maintain data integrity you have to either: use higher quality cables which increases cable costs (such as going fiber optic); or use repeaters placed in-line at shorter cable distances.

Personally, as an EE I would tend to go with the latter method since the vast majority of cases are going to have installations where cable length will not exceed ~10-20 meters.
As an example, the current HD-SDI specification is for a maximum cable length of ~100 meters (~320 feet) over RG6.
How many installs worldwide are actually using or require this amount of cable length.
In my opinion, if anyone wishes to go over ~20 meters, have them install repeaters (signal amplifiers/boosters).
Would we all prefer longer cable runs -or- SDI devices that don't randomly and easily fry.
But then I am not on the SMPTE committee.

*edit for minor typo*

Jon, I follow the RED user forum and they have had discussions about frying SDI ports on RED cameras. I don't follow Sony or ARRI forums so can't comment on those.



Sent from my iPad using Tapatalk

In your opinion, can the "Powerpack" from "Redrock" protect the SDI connector on the camera?

http://store.redrockmicro.com/Gimbal-Po ... ution.html

media.jpg (15.05 KiB) Viewed 13642 times

The IC is MACOM 21428. This is used in BMCC 2,5 K in decklink. The IC buring if error connection in SDI or over voltage present in BNC loop.

I replaced the IC with successful.

Repair is difficult but with good station smd is possible.

Bye

repair sequence

repair sequence

repair sequence

the Production 4k camera also use macom chip? is the same model?

Thanks David,

I actually think it's ludicrous a professional product can break so easily!! Is there no way camera manufacturers can fix such an issue?

I've never heard of SDI ports being burnt on the Alexa, Red's, Sony f5, f55 etc

One time on Alexa old, two time on AlexaMini, and some my friends on RedOne...
Sdi MUST connected on product turned off... when happened instead to attend a minutes to boot up camera we need to attend more to replace it...


Inviato dal mio iPhone utilizzando Tapatalk

repair sequence

Hi! Can you please tell me if the same SDI chips are used in BMCC 2.5K and BMPC 4K?