My Osmo is completely unresponsive. I left it in the case, unused, for a couple months (battery removed). When I pulled it out and put in a fully charged battery I got no response. No LED lights, no beeps. Absolutely nothing. I have tried suggested "reset" sequences with the buttons. No success. I have tried multiple fully charged batteries with no success.

Hi, sorry for the inconvenience. Did you manage to assess your DJI Osmo's battery? Please see the video below.

I'm having the same problem.  and I don't have a multimeter.  

I'm having the same issues as this and have no multimeter to check :/ Has anyone found a fix?