Thread: The SDI issues

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  1. #11  
    Senior Member Jacek Zakowicz's Avatar
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    Quote Originally Posted by Christoffer Glans View Post
    I wonder about this as well. If it's a problem that can be totally avoided by just using monitor batteries instead of a P-Tap or 2-pin from the camera battery, then there's nothing to worry about? Right?
    If it is a ground loop you need to wait for the camera to power up before connecting the video. Usually during the power up sequence the current spike gets through the common ground for video and power and damages the video board that is not designed to handle such a current. It is a common problem with audio/video devices used in common power/ground systems where hi power is required. I must add that if the camera is used on a crane that needs massive power to operate that can happen during the shot when the crane moves fast. In that case it's best to use separate power source for the camera. This is my understanding, anyway. We used the little noise supressor transformers to isolate the video ground completely...
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  2. #12  
    Senior Member Robert Hofmeyr's Avatar
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    Quote Originally Posted by Jacek Zakowicz View Post
    If it is a ground loop you need to wait for the camera to power up before connecting the video.
    Not sure if this is the case. Red advises to connect power first, then SDI, then boot.

    Christoffer, according to the Komodo manual we need to "Always connect the DC power cable (or batteries) before connecting the BNC SDI cable." It is not clear whether this refers to the power source for the camera or the monitor.

    The page on red.com (https://support.red.com/hc/en-us/art...to-SDI-Outputs) says:

    First, connect the power source to the SDI accessory.
    Next, connect the BNC cable to the camera, then accessory.
    Lastly, power the camera and accessory on/off.

    And for detaching the monitor:

    First, shutdown the camera and the SDI accessory.
    Next, disconnect the BNC cable from the camera, then accessory.
    Lastly, disconnect the power source from the SDI accessory.

    If we must follow these rules, it does seem that the SDI cable should be disconnected before changing the battery on the monitor.
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  3. #13  
    Senior Member Christoffer Glans's Avatar
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    Quote Originally Posted by Robert Hofmeyr View Post

    If we must follow these rules, it does seem that the SDI cable should be disconnected before changing the battery on the monitor.
    For having an on-camera monitor in a run n gun-type shoot, this is actually ridiculously unpractical. It would mean that we need to power down everything, disconnect everything and then change the monitor battery before powering everything up again. Can we ask the subject to put on coffee while we wait for this?

    I would assume that these problems only relate to when you actually connect and disconnect stuff. But whenever everything is connected we should be able to work without thinking of disconnecting before changing batteries. I've never heard of these problems with HDMI, but I'm starting to feel like having HDMI out would have been better on the camera. Now I'm thinking that I maybe shouldn't get an SDI monitor at all because of all these risks.

    Couldn't Red just pull some power from the top display and feed that to an external display connected like we used to do on DSMC2? Everyone keeps saying that there's not enough power in the Komodo to drive a monitor like we used to do, but there's a monitor on top that draws power, so why couldn't we just have a larger one able to be connected on the top?
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  4. #14  
    Senior Member Robert Hofmeyr's Avatar
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    Quote Originally Posted by Christoffer Glans View Post
    For having an on-camera monitor in a run n gun-type shoot, this is actually ridiculously unpractical. It would mean that we need to power down everything, disconnect everything and then change the monitor battery before powering everything up again. Can we ask the subject to put on coffee while we wait for this?

    I would assume that these problems only relate to when you actually connect and disconnect stuff. But whenever everything is connected we should be able to work without thinking of disconnecting before changing batteries. I've never heard of these problems with HDMI, but I'm starting to feel like having HDMI out would have been better on the camera. Now I'm thinking that I maybe shouldn't get an SDI monitor at all because of all these risks.

    Couldn't Red just pull some power from the top display and feed that to an external display connected like we used to do on DSMC2? Everyone keeps saying that there's not enough power in the Komodo to drive a monitor like we used to do, but there's a monitor on top that draws power, so why couldn't we just have a larger one able to be connected on the top?
    I do think reds recommendation is overcautious. Pretty sure when attaching a battery to a monitor it won't cause a ground loop and fry the SDI. Would be great to have confirmation though.

    I am still hoping Red makes a small touch monitor that powers from the top pogo. Maybe it's not possible, but I hate cables and rigging is especially messy when the video out is pretty much as far from the monitor as possible.
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  5. #15  
    Senior Member Christoffer Glans's Avatar
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    Quote Originally Posted by Robert Hofmeyr View Post
    I do think reds recommendation is overcautious. Pretty sure when attaching a battery to a monitor it won't cause a ground loop and fry the SDI. Would be great to have confirmation though.

    I am still hoping Red makes a small touch monitor that powers from the top pogo. Maybe it's not possible, but I hate cables and rigging is especially messy when the video out is pretty much as far from the monitor as possible.
    It doesn't even have to be using onboard power. Just make a monitor that can be attached from the top connector, both directly or using a Red Arm for flexibility, and then have that monitor use monitor batteries. Preferably BP batteries since that's the infrastructure of the camera itself.

    Why can't this be a reality and we can ditch using SDI altogether.
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  6. #16  
    Senior Member Alex Lubensky's Avatar
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    Quote Originally Posted by Christoffer Glans View Post
    For having an on-camera monitor in a run n gun-type shoot, this is actually ridiculously unpractical. It would mean that we need to power down everything, disconnect everything and then change the monitor battery before powering everything up again. Can we ask the subject to put on coffee while we wait for this?

    I would assume that these problems only relate to when you actually connect and disconnect stuff. But whenever everything is connected we should be able to work without thinking of disconnecting before changing batteries. I've never heard of these problems with HDMI, but I'm starting to feel like having HDMI out would have been better on the camera. Now I'm thinking that I maybe shouldn't get an SDI monitor at all because of all these risks.

    Couldn't Red just pull some power from the top display and feed that to an external display connected like we used to do on DSMC2? Everyone keeps saying that there's not enough power in the Komodo to drive a monitor like we used to do, but there's a monitor on top that draws power, so why couldn't we just have a larger one able to be connected on the top?
    You don't have to disconnect everything to change the battery. You are totally correct saying that those problems can occur while connecting/disconnecting stuff. Usually SDI can occur problems in two occasions - first and the most common is when you're connecting/disconnecting the sdi cable. Second is if you're having a non-grounded playback monitor connected to 220V on an sdi cable straight to the camera - it can send some voltage over SDI resulting in the SDI input burnout. At least it's the problems I've ran into myself or know people who have burned SDI's on Alexa's.

    If your SDI cable is faulty - it can also cause damage to the camera on battery change even while being connected.
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  7. #17  
    Senior Member Christoffer Glans's Avatar
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    Quote Originally Posted by Alex Lubensky View Post
    You don't have to disconnect everything to change the battery. You are totally correct saying that those problems can occur while connecting/disconnecting stuff. Usually SDI can occur problems in two occasions - first and the most common is when you're connecting/disconnecting the sdi cable. Second is if you're having a non-grounded playback monitor connected to 220V on an sdi cable straight to the camera - it can send some voltage over SDI resulting in the SDI input burnout. At least it's the problems I've ran into myself or know people who have burned SDI's on Alexa's.

    If your SDI cable is faulty - it can also cause damage to the camera on battery change even while being connected.
    Sure, but how come so many report issues with the SDI on Komodo? Excluding those who just don't read the proper manual or procedures, if you use a 12G cable, follow the procedures and use a monitor with its own batteries, shouldn't that be impossible to short by normal use? Like, keeping everything connected all the time, changing batteries and restarting monitor and cameras over and over?

    I still think a BP powered monitor that connects to the top of the camera or cable from the top of the camera would be in Red's interest. Imagine how many cameras might get sent in to be fixed because of SDI issues. All while we have a component shortage. It might lead to not only a backorder for new cameras but for repairs as well. Hopefully, the stutters and latency with Komodo Link could be solved so we could use that as a more viable option. Right now it's not very good for critical viewing.
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  8. #18  
    No Alex, you are wrong. As it is you need to unplug the SDI cables every time you connect power, batteries or 2pin power cables.

    Simply if the + pol of the power source gets in contact before the - pol or ground, then as power tend to rush the easiest path it might travel trough your SDI cable and ruin your video board.

    Arri guy explains it here: https://www.arri.com/resource/blob/1...eller-data.mp4

    And yes it´s crazy.

    I find it amazing that its 2021 and still there is not a secure power cable and or video connector standard in the industry that prevent shit like this.

    Having to unplug video before swapping or connecting power is nuts. I just don´t do it. I have taken my chances and so far had no problems. But my friend just had a Komodo here in Stockholm fried this way... He is the biggest red customer I know, still the repair time he said is several months.


    Seams like there should be an easy fix for this with some sort of component that dictates the polarity and voltage that can run trough the SDI Tap.
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  9. #19  
    Is this only an issue when using an external power cable (DC-IN) or also when using a battery plate that connects through the battery slots of the camera?

    The ARRI guy is specifically talking about this issue when plugging in an external power cable.

    If so, using a plate like the Core SWX would be safer than a power source that connects through the DC-IN of the camera.
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  10. #20  
    Senior Member Robert Hofmeyr's Avatar
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    Quote Originally Posted by Björn Benckert View Post
    No Alex, you are wrong. As it is you need to unplug the SDI cables every time you connect power, batteries or 2pin power cables.
    Do we need to unplug SDI even if we are changing the battery on the monitor only?

    What about swapping out a BP-9 on the back of the Komodo. eg replacing a depleted battery while the other battery continues to power the camera?
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