Image distortion/tearing with light to dark images

[CurtisT 0]

I have been battling a difficult video issue with my Attitude V2 goggles for a few months now and came across this site while researching the details of the fatshark rx modules.  Hopefully someone can give me some direction in further troubleshooting.

I have 2 sets of fatshark attitude v2 goggles.  On both sets I have removed the FS rx module and added a female pin header to accept newer diversity modules.  I have a eachine pro58 and a realacc5808 module.  I have been using these goggles/modules for over a year with no trouble with several quads with and without OSD. I recently built a new fpv quad with an FC with built in OSD and noticed I'm getting distortions in the video that fluctuate with the lighting conditions in the image.  I initially tried various parts swaps, multiple FCs, cams, vtx, and different receivers; and it always came down to any FC/OSD I purchased this year have the issue (4 of them) and anything older works fine. I have a boscam fpv watch and the image looks perfect on it all the time.  Also a DVR connected to the goggles records the image fine.  But when I use these newer FC/OSD I get this distortion in the screens of the goggles.  I purchased an original Fatshark rx module and board its soldered to and put that in my goggles.  The issue went away.  So I believe there is some compatibility issues with my diversity rx modules and newer OSDs on race quad FCs.   I thought it might be a vsync issue but am not sure or know how to check.  Video of the issue below: 

 

 

 

I found this post, and some of the info looks like it may apply to my issue.  Perhaps a coupling cap on the rx signal would help me?

 

[Mr.RC-Cam 124]

The popular diversity vRx modules have a design issue that results in incorrect video levels (low amplitude). So maybe the new OSD is also contributing to this issue and the combination results in a video level that is incompatible with the goggles. Just a best-guess; Without an o-scope measurement it is difficult to know what the real issue is.

This DiY tool will help you check for incorrect video levels:
https://www.rc-cam.com/forum/index.php?/topic/4126-diy-fpv-video-calibration-tool-low-cost/

 

[CurtisT 0]

Thanks!  I'll give it a shot.  Since I only have the issue when running the video signal through these FCs I am curious to know if they are changing the levels even if there isn't much I can do about it.