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 1 (click to view)
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Commercial Microwave Oven Owner's Manual RFS9MP* RFS11MP*
* Additional alphanumeric characters representing other models in the series may follow each model number. Keep these instructions for future reference. If the oven changes ownership, be sure this manual accompanies oven.