Tag Archives: power

SDI Failures and what YOU can do to stop it happening to you.

Sadly this is not an uncommon problem. Suddenly and seemingly for no apparent reason the SDI output on your camera stops working. And this isn’t a new problem either, SDI ports have been failing ever since they were first introduced. This issue affect all types of SDI ports. But it is more likely with higher speed SDI ports such as 6G or 12G as they operate at higher frequencies and as a result the components used are more easily damaged as it is harder to protect them without degrading the high frequency performance.

Probably the most common cause of an SDI port failure is the use of the now near ubiquitous D-Tap cable to power accessories connected to the camera. The D-Tap connector is sadly shockingly crudely designed. Not only is it possible to plug in many of the cheaper ones the wrong way around but with a standard D-Tap plug there is no mechanism to ensure that the negative or “ground” connection of the D-Tap cable makes or breaks before the live connection. There is a however a special but much more expensive D-Tap connector available that includes electronic protection against this very issue – see: https://lentequip.com/products/safetap

Imagine for a moment you are using a monitor that’s connected to your cameras SDI port. You are powering the monitor via the D-Tap on the cameras battery as you always do and everything is working just fine. Then the battery has to be changed. To change the battery you have to unplug the D-Tap cable and as you pull the D-Tap out, the ground connection disconnects fractionally before the live connection. During that moment there is still positive power going to the monitor but because the ground on the D-Tap is now disconnected the only ground route back to the battery becomes via the SDI cable through the camera. For a fraction of a second the SDI cable becomes the power cable and that power surge blows the SDI driver chip.

After you have completed the battery swap, you turn everything back on and at first all appears good, but now you can’t get the SDI output to work. There’s no smoke, no burning smells, no obvious damage as it all happened in a tiny fraction of a second. The only symptom is a dead SDI.

And it’s not only D-Tap cables that can cause problems. A lot of the cheap DC barrel connectors have a center positive terminal that can connect before the outer barrel makes a good connection. There are many connectors where the positive can make before the negative.

It can also happen when powering the camera and monitor (or other SDI connected devices like a video transmitter) via separate mains adapters. The power outputs of most of the small, modern, generally plastic bodied switch mode type power adapters and chargers are not connected to ground. They have a positive and negative terminal that “floats” above ground at some unknown voltage. Each power supplies negative rail may be at a completely different voltage compared to ground.  So again an SDI cable connected between two devices, powered by different power supplies will act as the ground between them and power may briefly flow down the SDI cable as the SDI cables ground brings both power supply negative rails to the same common voltage. Failures this way are less common, but do still occur. 

For these reasons you should always connect all your power supplies, power cables and especially D-Tap or other DC power cables first. Then while everything remains switched off connect the SDI cables. Only when everything is connected should you turn anything on. If unplugging or re-plugging a monitor (or anything else for that matter) turn everything off first. Do not connect or disconnect anything while any of the equipment is on.  Although to be honest the greatest risk is at the time you connect or disconnect any power cables such as when swapping a battery where you are using the D-Tap to power any accessories. So if changing batteries, switch EVERYTHING off first, then disconnect your SDI cables before disconnecting the D-Tap or other power cables next.

(NOTE: It’s been brought to my attention that Red recommend that after connecting the power, but before connecting any SDI cables you should turn on any monitors etc. If the monitor comes on OK, this is evidence that the power is correctly connected. There is certainly some merit to this. However this only indicates that there is some power to the monitor, it does not ensure that the ground connection is 100% OK or that the ground voltages at the camera and monitor are the same. By all means power the monitor up to check it has power, then I still recommend that you turn it off again before connecting the SDI).
 
The reason Arri talk about shielded power cables is because most shielded power cables use connectors such as Lemo or Hirose where the body of the connector is grounded to the cable shield. This helps ensure that when plugging the power cable in it is the ground connection that is made first and the power connection after. Then when unplugging the power breaks first and ground after. When using properly constructed shielded power cables with Lemo or Hirose connectors it is much less likely that these issues will occur (but not impossible).

Is this an SD fault? No, not really. The fault lies in the choice of power cables that allow the power to make before the ground or the ground to break before the power breaks.  Or the fault is with power supplies that have poor or no ground connection. Additionally you can put it down to user error. I know I’m guilty of rushing to change a battery and pulling a D-Tap connector without first disconnecting the SDI on many occasions, but so far I’ve mostly gotten away with it (I have blown an SDI on one of my Convergent Design Odysseys).

If you are working with an assistant or as part of a larger crew do make sure that everyone on set knows not to plug or unplug power cables or SDI cables without checking that it’s OK to do so. How many of us have set up a camera, powered it up, got a picture in the viewfinder and then plugged an SDI cable between the camera and a monitor that doesn’t have a power connection yet or already on and plugged in to some other power supply? Don’t do it! Plug and unplug in the right order – ALL power cables and power supplies first, check power is going to the camera, check power is going to the monitor, then turn it all off first, finally plug in the SDI.

3rd Party BP-U style batteries And Sony Camcorders (Update)

I wish to update and present the facts that I have regarding potential issues with mainly older 3rd party PB-U batteries. This isn’t here as a scare story, I’m not trying to sensationalise this, just present the facts that I have to hopefully clarify the current situation.

In 2019 I became aware that it was suddenly becoming very hard to buy 3rd party BP-U batteries. Dealers didn’t have any and you couldn’t find them anywhere. Talking to a couple of manufacturers I was informed that they had been told to stop making BP-U batteries.

Then I learnt from Sony that they had been getting an unusually large number of cameras in for repair, cameras that had suddenly and inexplicably stopped working. This they had traced to design issues in some 3rd party batteries. 

As a result of this Sony took action in 2019 to prevent the manufacture of 3rd party BP-U batteries and that’s why you could no longer get them.

Since then however it would appear that the manufacture of 3rd party batteries is once again in full swing. In addition I’ve noticed that some older models have been discontinued, often with new versions replacing them, perhaps a “B” version or a model number numerically higher than before.

From this I must assume that whatever the issue was, it has now been resolved and that the 3rd party BP-U batteries on sale today should be perfectly safe to use with our cameras. I would have no hesitation in today buying a brand new BP-U battery from any of the reputable brands.

I have nothing to gain here. This is not a campaign to make you all buy Sony batteries. Even though Sony do make a very fine battery, I too use 3rd party batteries as I need the D-Tap port found only on 3rd party batteries.

But clearly there was a very real battery issue. I’m led to understand that the cost to repair these damaged cameras was over $1K. While not every user of these batteries ends up with a dead camera, I think you have to ask yourself – is it worth using batteries made in 2019 or earlier? I won’t list the batteries that I know to have problems because the list may be incomplete. Just because a battery is not on the list it would not be a guarantee that it’s safe. However if any 3rd party battery manufacturer is reading this and has the confidence to provide me with a list of batteries that they will guarantee are safe, I will gladly publish that.

Clearly not everyone ends up with a dead camera, perhaps the majority have no issue, but enough did that Sony had to take action and it appears that the manufacturers responded by checking and adjusting their designs if necessary.

So my advice is: Don’t use 3rd party batteries made prior to 2020.  

If you do, then make absolutely sure the camera is completely powered down when inserting or removing the battery. 

I believe that any BP-U battery made in 2020 or later should be safe to use. So please think about replacing any old batteries with new ones, or perhaps contact your battery supplier and ask if what you have is safe. However you should be aware that since 2019 Sony’s own BP-U battery chargers will no longer charge 3rd party batteries.

The information I have presented here is correct to the best of my knowledge and I hope you will use it to make your own decision about which batteries to use.

Why Can’t I Get Third Party BP-U Batteries any more?

In the last month or so it has become increasingly hard to find dealers or stores with 3rd party BP-U style batteries in stock.

After a lot of digging around and talking to dealers and battery manufacturers it became apparent that Sony were asking the manufacturers of BP-U style batteries to stop making and selling them or face legal action. The reason given being that the batteries impinge on Sony’s Intellectual Property rights.

Why Is This Happening Now?

It appears that the reason for this clamp down is because it was discovered that the design of some of these 3rd party batteries was such that the battery could be inserted into the camera in a way that instead of power flowing through the power pins to the camera, power was flowing through the data pins. This will burn out the circuit boards in the camera and the camera will no longer work.

Users of these damaged cameras, unaware that the problem was caused by the battery were sending them back to Sony for repair under warranty. I can imagine that many arguments would have then followed over who was to pay for these potentially very expensive repairs or camera replacements.

So it appears that to prevent further issues Sony is trying to stop potentially damaging batteries from being manufactured and sold.

This is good and bad. Of course no one wants to use a battery that could result in the need to replace a very expensive camera with a new one (and if you were not aware it was the battery you could also damage the replacement camera). But many of us, myself included, have been using 3rd party batteries so that we can have a D-Tap power connection on the battery to power other devices such as monitors.

Only Option – BP-U60T?

Sony don’t produce batteries with D-Tap outlets. They do make a battery with a hirose connector (BP-U60T), but that’s not what we really want and compared to the 3rd party batteries it’s very expensive and the capacity isn’t all that high.

BP-U60T Why Can't I Get Third Party BP-U Batteries any more?
Sony BP-U60T with 4 pin hirose DC out.

So where do we go from here?

If you are going to continue to use 3rd party batteries, do be very careful about how you insert them and be warned that there is the potential for serious trouble. I don’t know how widespread the problem is.

We can hope perhaps that maybe Sony will either start to produce batteries with a D-Tap of their own. Or perhaps they can work with a range of chosen 3rd party battery manufacturers to find a way to produce safe batteries with D-Tap outputs under licence.

Beware multiple power supplies!!

From time to time someone will pop up on a forum or user group with tales of fried SDI boards, dead monitors or dead audio devices. Often the reason for the death of these units seems obscure. One day it all works fine, the next time the monitor is plugged in it stops working.

A common cause of these types of issue is the use of individual power supplies for each device. Most modern power supplies use a technology called “switch mode”. Most “wall wart” power supplies are switch mode. Computers use switch mode power supplies, they are probably the most common type of power supply in use today.

The problem with these power supplies is that the voltage they produce is not tied to a common earth or ground connection. A 12 volt power supply may have an output voltage that measures 12 volts across it’s positive and negative terminals, which is great. But the negative terminal might be many volts above “ground”. Used singly this is not normally a problem but if you use a couple of different power supplies with negative terminals floating at different voltages, if you connect them together current will flow from one to the other as the establish a common base voltage.

As an example if you have a monitor powered by one power supply and a camera powered by another, when you connect the monitor to the camera current may flow down the SDI or HDMI cable from one power supply to the other causing damage to the chips that process the SDI/HDMI signals.

Even if there is no damage this current can lead to audio hum or other electrical noise.

How can you prevent this?

First use only high quality power supplies. Wherever possible try to run everything off a single power supply. Powering the camera from a high capacity power supply and then feeding any connected accessories via D-Tap or Hirose outputs on the camera is good practice. Also powering everything by batteries helps. If you must use separate power supplies then connect everything together before connecting anything to the mains and before turning anything on. This should ensure that any current runs through the shield and ground paths in the cables rather than possibly travelling down the delicate signal part of a connection as you connect things together.