The owner's manual/operating instructions that I purchased was the original factory document and it was in at least three and maybe more languages. I no longer have it because I sold the tape recorder and included the owner's manual/operating instructions and a service/repair manual that I bought on ebay for the new owner.
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.
Great price, Quick delivery, the document was very usefull A+++++++++++++++
Text excerpt from page 27 (click to view)
Operating Instructions
Tips on Baking
Tip Push a wooden skewer into the highest point of the This is how to tell if your cake cake. When no more cake mixture sticks to the wood, is cooked through you can switch off the oven and utilise the residual heat. The cake collapses (is sticky, Check your recipe. Next time use less liquid. Observe not properly cooked through, mixing times, particularly when using kitchen appliwater marks) ances. The cake is too light Cake with moist topping/ cake is not cooked through, is unevenly browned Next time select a dark cake tin or place the cake one level lower. Next time bake at a lower temperature and increase the cooking time.