Ok, I've searched here on DP and found no answers, and the answers I've found on the Interwebs is conflicting in 20 different directions with 20 different answers. So, here we go:

Got a Dreamcast that isn't retaining the time/date upon power-up. Internal battery is dead. Left the DC on for 48 hours, hoping to recharge it (it's a rechargable battery according to my research). After 48 hours, I powered down, waited 10 minutes, and turned on the DC. It asked me to input the date and time again.

Internal battery is dead, dead, dead.

1. Can this internal battery be replaced?
2. If so, what size/style battery does it take?
3. Does it have to be a rechargable battery?

I can't believe I'm having trouble finding a straight simple answer to this, as I would assume I'm not the first to encounter this problem. But every web site seems to offer different advice to correct this. Give me one answer. How did YOU deal with this?