I have just installed Lightbridge (I'm using A2 on a S900) and Zenmuse Z15 (GH4) gimbal today.
I cannot get any video signal despite going over it repeatedly, checking and double checking wiring, connections, firmware updates etc.
I'm using a Futaba T14 SG - have turned RF off and trainer port (master). I can program functions etc - just no video signal.
The HDMI out of the GH4 is working ok - I tested it on the TV.
Lightbridge video feed is working - put an HDMI feed from the Laptop directly into the Lightbridge air-side and it broadcast it instantly to my HDMI monitor.
But no feed coming from the Gimbal HDMI. The Gimbal switch is on HDMI - not AV.
When I power it up, the Gimbal does it's little thing, and works like should in all three modes.
I have a green light for 'Control', but constant red light for 'Video'.
I've re-linked it after fresh installs of firmware for A2, Gimbal, Lightbridge Ground and Air systems (several times each).

Previous to this, I've been flying the S900 with just the A2 for the past week to get used to it before installing Lightbridge and Gimbal.

I'm really stuck here... any ideas appreciated?

I forgot to say that I get the telemetry displayed on my HDMI monitor from the Lightbridge.

I'm having same issue here...

One guy said "test LB alone, without Z15" - i'm having hard times doing so right now, cant get video link.

1. How about the led light on the Gimbal?
2. Did you try different lightbridge to see if it works?
3. Make sure it is in HD Gimbal at the video source in the APP

Thanks to the S900 Facebook page I was offered the soloution: You have to turn HDMI on with an Android phone plugged into the Lightbridge ground station and using the App.
As I don't own one of those phones, and was just planning on using my HDMI monitor, I would have just assumed that the Lightbridge Assistant software would be able to set everything that I needed.
Unless there is something that I've missed in the literature (I don't think i have), DJI need to write this into their Lightbridge/Zenmuse setup instructions or enable that feature in the Lightbridge/Zenmuse assistant... It will save a lot of people tearing their hair out - I basically wasted two days of my life and developed an anxiety disorder over this!!

I have the same problem. I used a samsung tab and enabled usb debugging and connected fine with the app. i get the telemetry displayed on the tab but no picture.

- When i try to switch on the tab between hdmi and hd i get a failure msg
- Tested gh4 outport (on a tv)
- latest firmware (gimbal, lightbridge, a2)
- green light in the front of the gimbal
- tested connecting a gopro to the hdmi on lightbridge. (display picture in the lightbridge app)

post.abfilm Posted at 2015-4-23 18:52
I have the same problem. I used a samsung tab and enabled usb debugging and connected fine with the  ...

when you connected the GH4, how about the light on the gimbal?

DJI-Cathy Posted at 2015-4-24 18:39
when you connected the GH4, how about the light on the gimbal?

I have green light on the gimbal. A strange thing is if i disconnect the hdmi from the gh4  i still get a solid green light.

In the lightbridge Assistant i dont have a gh4 option. only 5d, bmpcc and gh3. Is this right ?

In the zenmuse Assistant i get firmware 0 at hd-av. When i update it i run the update as normal and get it verified. When i recycle the Power i still get firmware 0 at the hd-av. After i have done this 9-10 times i got to update to 1.1 and update 1.2 was ready to get download. After trying to update to 1.2 i got sucess but when i restarted i got version 1.1 again. TRied this many times and gave up. After a while i tried again but suddently its showing firmware 0 again. I have been strugling with this since i bought it (a couple of month ago) and never taken it outside for a fly
All the other firmware is ok.

post.abfilm Posted at 2015-4-24 18:44
I have green light on the gimbal. A strange thing is if i disconnect the hdmi from the gh4  i still ...

Did you ever get to the bottom of this? I also have no video and no GH4 option in my Lightbridge assistant. Any help would be greatly appreciated! Thanks

Just-inspire Posted at 2015-5-2 19:57
Did you ever get to the bottom of this? I also have no video and no GH4 option in my Lightbridge a ...

No sorry. Have sent in the gimbalt to service. ill let you know when i find out of it.  Please do the same

Just-inspire Posted at 2015-5-2 19:57
Did you ever get to the bottom of this? I also have no video and no GH4 option in my Lightbridge a ...

Just got a message from dji. We should choose gh3 for the gh4 gimbal