An Update on our gimbal problems:
We got our brand new, just shipped in from China, replacement gimbal, and at first we thought this had solved the problem. I fired up the S900 in my office, and the video feed was good. So I took it outside and left it in the garden for 30 minutes (ambient temp around 1ºC) - the video image was rock solid. So we charged everything up and went to test fly today. 2ºC and a chilling wind: lots of power cycles without luck and only 1 out of 4 flights with working video. During all these flights the pilot's camera and screen worked perfectly. We even did a successful RTH test, so know that all controls and communication are good.
We realise now, that once the HDMI board has got an image, it generates enough internal heat to keep it warm and the video feed working. So back in my garden we did some tests, which conclusively prove that unless the area around the base of the camera, and particularly the HDMI board are warm, you get a red fault LED on the board and no image. Once you have heated up the area (see video: 2 mins with a hair dryer) you get a green flashing LED and all works fine, however many times you power cycle. But then leave the S900 for 20 mins in the cold, and the image never appears, just a grey screen.
We think we have been sold goods that are not fit for purpose and will investigate our options....
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Video:
Video showing a temperature related problem with the DJI S900 Z15 GH4 Gimbal. This is a replacement gimbal and has the same problem as the first one we were supplied with. This is on a brand new, professionally built S900. We have done about 25 flights with the video feed only working on 30% of them. Our flight logs confirm it is on the cold days that we have this problem
We did this whole test twice with the same results
test sequence:
1. leave S900 outside for 30 minutes (outside temp 3ºC with light wind)
2. Switch on camera (4K 25 fps, but other settings yield the same result)
3. Power up S900 and gimbal several times - result: no image
4. Heat up underside of gimbal, where the HDMI board is located with a hair dryer for 2 minutes
5. Power cycle S900 and gimbal 3 times - result: good image every time
The video image works every time at room temperature and only becomes a problem once the ambient temperature goes down below around 5ºC
Solution in cold weather: use a hair dryer or temporarily attach a hand warmer to the underside of the gimbal before powering up
Why are we sure this is the problem?
1. With the camera removed from the gimbal, it outputs a perfect image to a monitor via an HDMI lead when cold, even at -6ºC ( we tested this in a freezer )
2. Video transmitters have been swopped over and both work with the GoPro/Pilot's camera
3. When in a warm office or above 7ºC the image works fine
4. This is the second gimbal that has exactly the same issues
