emusonacid! legacy

My new esi-32 from ebay won't remember it's settings after it's turned off and turned on again. I have another esi-32 that I have owned since 1995 and it has always remember it's settings, back light and sample settings when turned off and on again. With the new esi-32, I have to adjust the back light and sample settings every time I turn it on. I'm thinking there must be a battery that needs to be replaced. On the motherboard, there is a black rectangle box that I'm assuming there is a battery inside. I can't get that cover off without ripping it off and breaking it.

Has anyone else ever come across their esi not remembering the setting?