There's a disassembled view on here somewhere... I'd check voltage across the battery first, and then look for fuses or fusable links between the battery and the usb port.
I just checked mine. I don't find any movement in the mount, but I don't know how long it will last in desert heat. This thing may end up with a 1/4-20 nut and some JB Weld to construct a threaded mount.
I'd love to see an adapter to 1/4 - 20 so I could use my existing mounts. Looks like I may have to start with a chunk of aluminum and carve out anything that doesn't look like a mount - unless someone has an idea.
??