Turns out this was not the manual i was looking for. The concertmate 670 keyboard i have is a "Realistic" model made for Radio Shack and none of the diagrams on the owners manual i received matches up. HOWEVER, I must say the service Owners Manual provides was fast and efficient by being available online. The manual was in good readable condition and easily downloaded.
Thank´s for your help, I already recived these manual from you
Text excerpt from page 7 (click to view)
3.3. INSERTING THE BUTTON-TYPE BATTERY
The lithium battery is a critical component (Type No.: CR2025 Manufactured by Panasonic.) It must never be subjected to excessive heat or discharge. It must therefore only be fitted in equipment designed specifically for its use. Replacement batteries must be of the same type and manufacture. They must be fitted in the same manner and location as the original battery, with the correct polarity contacts observed. Do not attempt to re-charge the old battery or re-use it for any other purpose. It should be disposed of in waste products destined for burial rather than incineration.