Hello, my name is***** to Justanswer! Give me just a few minutes to look up some specifics, I'm working on this now.
There is an internal battery that needs to be replaced. The battery is what keeps the stored information on the keyboard when it's turned off. When the battery dies, there is no memory. You'll need to remove all of the screws from the bottom of the piano, to flip the top of the keyboard up. You'll see a round shiny battery, that's what needs to be replaced. There is a number on the battery, that is how to identify the replacement. You can get a replacement at any electronics store, or drug store.
Be sure to unplug the keyboard and let it sit for 10 minutes before starting to work on it.
Hmm, that changes things... How old is it? Did it used to keep the pedal settings?
Ok, and do you save the assignments before turning the piano off?
I'm not exactly sure why it's acting different than the 709, they use very similar software. I'm going to open this question back up, you will get a full refund if we cannot get this fully resolved.