My advice is take it to someone who works on electronics unless you want to DIY (not recommended) to get the battery replaced. BlackBerry ASY-34812-001 Mini External Battery Charger for BlackBerry D-X1 / F-S1 / F-M1 Battery - Bulk Packaging. I had to draw a diagram and mark certain pieces so I would know where they went and in what order they have to be re-attached. This item: BlackBerry OEM F-M1 Battery Pearl 9100 9105 Style 9670.

I will tell you that replacing most batteries is a very intricate job as, the bottom of the keyboard has to be removed, as well as a lot of the internal boards. Take a look at this AFTER you have gotten the battery replaced. the Korg M1, Korg T2-T3 and other keyboards all use the Yamaha Keystrip. I have worked on a Korg M1 Workstation and have had to replace the battery(CR2032) and then had to run a program called 'MIDI-OX' which also gave me access to the patches needed in order to restore the keyboard to factory patch settings. Yamaha Ref: VU8286701, replace V828670R / V8286700 Genuine Yamaha replacement.

However, if you can get a MIDI to USB converter and get the battery changed, then you can reload the patches back onto the keyboard. It sounds like your ROM battery, which the ROM contains and stores the patches for the keyboard, has gone completely dead and your keyboard is dead in the water.

Korg m1 replacement battery