I have recently lost the video and OSD data on my lightbridge output.("Connection broken" error).Gimbal  works fine and camera  records but I can't figure out whats gone wrong.
Setup is as follows.
DJI S900
A2
Zenmuse Z15HD
Panasonic Lumix GH4
Lightbridge with 2 TX setup.
Samsung Galaxy S5, set with debugging
The option for ground system decoder upgrade is not available when the ground system is connected to the LB assistant software.
I originally had an ipad but DJI have removed the app.As I don't have any spare components I can swap out I am limited to sourcing the problem.
I have tried the following
Connecting the camera HDMI output directly to a TV and it works.
Connecting a monitor to the Lightbridge HDMI output and it doesn't work.
All connections look solid
Green lights on gimbal (flashing front. Steady rear)
Latest firmware updates.
Could it be a camera setting? I have 4K down convert set to 1080p.
Any suggestions would be appreciated.

Dear all,
I found a BUG in the lightbridge and I think DJI should find a solution for us, because it played with us for too long.
I have a lot of Lightbridge and they dead one after each other as soon as their battery get discharged after long period where i didn't used them (If you stored it without charging it, you can have the problem also after one month).
As soon as the ground unit battery get fully discharged, the firmware of the device stops to work correctly. You can recharge the battery but, connecting it to the assistant, you will see just one of the 3 firmware component versions, and connecting the device to the smartphone, you will not be able to get connected and receive images.
The problem is described in detail on internet, in a lot of forums. You can read in example the following thread: http://www.phantompilots.com/threads/lightbridge-firmware.76946/
and http://www.phantompilots.com/thr ... irmware-hack.77073/
and http://www.rcgroups.com/forums/showthread.php?t=2091053
etc.etc.

I wrote that DJI is playing with us, because i returned 2 times my devices to DJI in order to solve this problem, but each time, if  the batteries get discharged, they get broken again.
We need a solution or a workaround because we work with these devices and it is not possible that I need to send to DJI the device each time that i need to work. Moreover I'm quite sure that after the guarantee period, DJI will not longer repair the unit for free. And moreover each time I have to pay the shipment to China and wait for the repair. This is not acceptable.
At least we should pretend a detailed problem description.
I discovered a lot of things about this device, by reading the second link i posted.

Regards
Emanuele

this is the solution: http://www.phantompilots.com/thr ... sistant-tool.77073/