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 17 (click to view)
1. 2.
Push down on the battery cover to open the battery compartment. Insert a 9V battery into the battery compartment according to the correct polarity as shown in Figure 14. Then push up on the battery cover to close the battery compartment. 3. The LED indicator will flash briefly when power is turned on to indicate normal battery status. If no flash occurs it has either no battery, the battery is drained or installed incorrectly. Change accordingly. 4. 4-Pin Jack: Volume can be adjusted by the gain control. Gain control has no effect when the switch is in the �GT� position (Guitar). 4-Pin Jack: Align and insert the 4-pin plug into the jack accordingly and tighten it in the clockwise direction as shown in Figure 15.