Huh. Thanks for the tips, and sorry to take so long to reply, this is just such a depressing issue that it takes a lot of willpower to force myself to think about it.
The thing is, when I plug it in, I get a solid white light that stays solid for the next 5 or 8 hours, and only then begins to blink, which is why I assume that's to indicate "charge complete."
I'm using the same charger I've always used with it, which is good for 1 amp. For the sake of argument though I'll try it on my 2+ amp charger/USB cord that is normally reserved for my phones/tablets which won't respond to anything under 2A. I don't have high hopes for this to do anything different, but it certainly can't hurt. I'll report back tomorrow.