Vintage Synth Repair

Hi,

I am having problems with my Roland XP-10. After receiving 
the "Battery Low" message flash across my screen, I proceeded to 
change out the internal battery. After changing it and turning the 
keyboard back on, I still receive the "Battery Low" message. Also, the 
screen seems to 'flicker' around.  There is no audible sound, except 
static, and everytime I touch the keys, the screen seems to flicker a 
lot more.  Any help is appreciated.

Alex