Problem: My Vortex won't save user registers

[Ed Drake <ejmd@erols.com>]

Hello fellow loopers (and loopettes!)
First of all, seasons greetings and Happy New Year to all!

Lately my vortex doesn't want to save any user registers that I create.
Thankfully I haven't created that many, but I was wondering if anyone knows
if there is some sort of battery inside to store registers in memory. I
figured I would check here on the list first before I contact Lexicon or
open up the vortex. The manual doesn't mention anything about this so I was
wondering if anyone else here knows.
Much thanks in advance and I eagerly await any replies.
Ed