Chosen Solution
My Rumble seems to have a loose contact on the power supply . (inside the device, not in the charging cable) I tried to open it, by removing the two screws under the sticker on the back, but this had no effect. I don’t even know which parts these screws hold together.
Here’s a link to a quick 90 second video showing how to fix the faulty JBL ONbeat Rumble power issue. https://www.youtube.com/watch?v=5rwajkjQ…
