I have the same camera at

I have the same camera at work but I’m on vacation so I can’t verify my suggestion.
Set the camera shooting mode to SD instead of HD and see if that works.
If it doesn’t, ask your question on the only decent forum I’ve found for this and similar JVC cameras.
http://www.dvinfo.net/forum/jvc-gy-hm-600-700-800-series-camera-systems/

Mike