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 9 (click to view)
Volume or tone adjustment does not affect recording.
To clean the cabinet
Use a soft cloth lightly moistened with mild detergent solution. Do not use strong solvents such as alcohol, benzine or thinner.
Turn VOLUME to adjust.
The T-BASS system enhances the realism of lowfrequency sound. Set T-BASS to ON or OFF.
To clean the heads
When the tape heads are dirty; - high frequency sound is not emitted - the sound is not adequately high - the sound is off-balance - the tape cannot be erased - the tape cannot be recorded on After every 10 hours of use, clean the tape heads with a head cleaning cassette. Use separately sold dry-type or wet-type cleaning cassette. Refer to the instructions of the cleaning cassette for details.
To clean the lens
Use a cotton swab slightly moistened with cleaning fluid. Wipe gently from the center to the edge.