Maybe a lot of these Apple AA chargers are faulty? Anyone have a good one? I'll request a warranty swap later just to be safe. There's always the hope that some manufacturing defect has been resolved.
Meanwhile, the above tips helped me. Thanks!
I was using brand-new Eneloops (should be identical to Apple's included batteries) on their very first re-charge. No good! Flashing orange every time.
- Plugging the charger into the wall first did not help (though I don't doubt it might help in other cases). Nor did trying different wall outlets.
- Cleaning the contacts and the batteries did not help (but is obviously good practice).
- Wiggling the batteries and shifting them slightly in different directions did not help... at first. (The flashing would often go steady for a few seconds, but then return to the error blink before long.)
BUT: wiggling them every which way, waiting to see what happens, then trying again... and again... and again... MANY times... DID eventually help!
So don't give up too soon on the wiggling/re-seating. And if/when you do get the light to stay on... back away softly and don't even breathe! The connection is incredibly fragile. (But not in the way you'd expect: it DOES connect with the batteries enough to know they're there, or else the light would simply be off. So what is the wiggling really doing? I don't get it.)