Not to long ago my RX lost all of its saves, but luckily I had them all backed up on my TB. I don't know if it was just some sorta freak incident or if the capacitor is starting to fade, it does make me curious. I wonder how hard would it be to pop open the Duo and replace it. I wouldn't think it would be much more than a soldering job after you figured out which one was bad and what would be a suitable replacement. Of course I could be wrong and would appreciate a little insight into how easy it would be to fix. If someone took the time to take a few pictures and point out what to change and specs of the parts needed it would be a boon.
On another note the TB is an awsome accessory. Knowing that you have a back up or two is certainly reassuring. I wouldn't mind opening a dead one if I come across it. Maybe after fiddling with it I can find a way to separate the card without causing irreversible damage to it. I wouldn't be surprised if it used a CR2032 battery seeing as how every system I've had to open up and replace a battery too uses them. The Saturn does, the Dreamcast memory cards do, I believe the Sega CD does as well as SNES carts. I haven't opened an NES cart but they probably use them as well. It would be nice if they did since the battery can be gotten at virtually any place that deals in electronics.
My friend, you're in luck:
1. Search for an old thread by D-Lite. He discusses the capacitor issue (in his experience, the quality of the capacitors used in the DUO is suspect, as many of them have been failing over the years). IIRC, replacing the capacitor is pretty easy. He has photos and step-by-step instructions. His website is
www.multimods.com .
2. A fellow member here posted some pics of a TB (or a Populous) HuCard autopsy. I don't think he determined the exact type / size of battery used, but I'm sure he kept everything and we can get that info from him. Unfortuantely, it seems that there is no easy way to crack open the HuCard, but then again, I've never done any of this stuff myself.