More details:
If I remove the main battery from the 250, it boots in the Dock! Even with extensions on. But when I reinserted the main battery and tried it again, I got the chimes of death. Then after letting it sit for a minute, it went back to the old behavior of shutting down midway through booting.
If I remove the main battery from the 230, it also boots in the Dock!
So it seems like these batteries are so dead that they somehow prevent the Duos from booting normally, even when they're being powered by the Dock. Weird.
I wonder if it's possible to rebuild a Duo battery?
If I remove the main battery from the 250, it boots in the Dock! Even with extensions on. But when I reinserted the main battery and tried it again, I got the chimes of death. Then after letting it sit for a minute, it went back to the old behavior of shutting down midway through booting.
If I remove the main battery from the 230, it also boots in the Dock!
So it seems like these batteries are so dead that they somehow prevent the Duos from booting normally, even when they're being powered by the Dock. Weird.
I wonder if it's possible to rebuild a Duo battery?