The Yamaha YS200 is a DC-powered keyboard; however, the keyboard's memory unit uses a battery. If you see a "Low Battery" warning, it's time to replace your battery. According to the YS200 user manual, you'll likely have to replace the battery at least once every five years. To guarantee compatibility, use only the battery specified. This will prevent problems. You can purchase the CR2025 battery at many electronics stores.
Press the "Power Off" button located on your Yamaha keyboard's rear panel to turn the power off. This prevents data loss when you are removing the memory.
Grasp the memory card and slide it upward to remove it from its slot. It's located in the upper-left corner of the keyboard.
Remove the screw from the card with your Phillips screwdriver. Insert the corner of your fingernail into the battery panel and pry upward to remove it. Inside you'll see the battery.
Lift the battery out of its compartment. Insert the new battery. Make sure the plus (+) sign is facing up.
Snap the cover back on. Replace the Phillips screw. Reinsert the card into the Yamaha keyboard's slot. Power the unit back on.