Could try “Draining the battery-backed RAM”
I got this from the Wayback Machine (Internet Archive) of the old Kurzweil Launchpad.
"Draining the battery-backed RAM
Sometimes a hard reset won’t correct your problem, so you must clear all the battery-backed RAM. This usually does the trick. Kurzweil suggests always doing a hard reset upon powering up, so you will also completely reset the Master Table back to the factory defaults. The Master Table contains the parameters on the Master page, Effects page, 3 MIDI pages, and the Song Mode MAIN and MISC pages. The above also applies to the Faders object, for K2500 keyboards.
How to drain battery-backed RAM on K2000/K2vx/K2500s
Remove the 3 AA batteries from your Kurzweil (accessable from the bottom of keyboards and on the back panel of rack models) and let it sit 30-60 minutes so the battery-backed RAM will drain. Nothing needs to be restored, although it is suggested that you do a hard reset when you power back up."
Here’s a link to that page: https://web.archive.org/web/20060616085358/http://www.k2users.org/k2/k_aid.htm