You can look at this discussion: Re: Atlas 550 Loses Config, but if the ATLAS is still under warranty you should return it for repair. The U4 chip is a through-hole chip and can be desoldered, replaced, and the replacement chip soldered back in place.
Hope this help,
It sounds like a Dallas/Mostek timekeeper chip. Rather than solder the replacement in place, solder in a socket. In another few years you'll be glad you did.