I had my Phantom setup done by a pro. Worked great until I took the  camera off to add the MicroSD card. Also the GoPro 3 did an update. Now  when I connect the camera to the drone, I get on the Pearl display iOsd  telemetry but no video. When the camera is off the Pearl shows USB  connected. When I turn the camera on, the GoPro red light turns on,  Pearl screen goes a nice black background and all telementry but no  video. Any suggrestions?

As silly as it sounds ,I once experienced this same issue.
I call it silly because my solution was pushing the USB Video Connection very tightly into the camera.
Uncomfortably tight.
Other than that ,I would say remove the camera's battery.
Wait a few (3-5) minutes.
Reassemble unit and give it a test run.
Hope this helps.

Thanks I will try that. hopefully that works.

So checked the cables and connection. Replaced cable to USB with spare cable and still no video. Tried changing channels and nothing. Checked the cable from gimble to filter and was good. AAAAHHHH!!!!

Maybe the GoPro was switched out of NTSC when it was updated? I feel like the update is the culprit since it sounds like all the connections are solid. If the GoPro is not in the same mode as the screen (NTSC not PAL), then you won't get a picture. Just a thought. If not maybe you should re-update the GoPro.

So this is the problem.  Apparently GoPro and DJI are having a messy divorce. If you have a GoPro 3 or less, DO NOT DO THE UPGRADE.  GoPro accidentally announced the release of their Drone with camera, and sent an update to those with GoPros to turn off the video out from the GoPro USB. This has made the cameras useless with DJI, unless someone can make a fix.

Homer Simpson Posted at 2016-2-13 10:54
So this is the problem.  Apparently GoPro and DJI are having a messy divorce. If you have a GoPro 3  ...

Can you share a link with this factoid?
I cannot fathom GoPro rendering their cameras useless, hell, DJI has surely helped their sales to a degree....

So, there was a recent update for GoPro 3 and 4 this year. The new update disables the ability to use the USB as a video out in FPV. How did I find this out? I did the update, and no video. Called GoPro, and they said they were changing the code so they can enter the market with their drone, see link below. So I took the GoPro back to Costco, swapped it for a new 3, tried it before the software upgrade and worked. Did the upgrade and no video. Apparently there have been many complaints to GoPro for this move. I again took the camera back for another new one, telling Costco that GoPro told me to since the update did not take. Here is the kicker, the GoPro 4 USB is different, therefore the update did not shut off it's video.

http://shop.gopro.com/drones/karma/2016.html

Homer Simpson Posted at 2016-2-12 21:54
So this is the problem.  Apparently GoPro and DJI are having a messy divorce. If you have a GoPro 3  ...

I second don't do an upgrade; If it isn't  broke don't fix it. if your quad is working fine don't up grade. why ask for problems. if you have already upgraded; maybe you can go back to something that works. I never could understand why any one would want to up grade a perfectly good drone.

melvonnar@yahoo Posted at 2016-2-27 15:33
I second don't do an upgrade; If it isn't  broke don't fix it. if your quad is working fine don't  ...

I took the camera back to Costco and replaced it. Apparently I was not the only one.