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 44 (click to view)
6. SETTING AND ADJUSTMENTS BEFORE SHOOTING
6-4 Back Focus Adjustment
3. 4. 6. 5.
It is only necessary to perform this when the lens is attached for the first time or when focusing is not correct in both the telephoto and wide-angle positions. Adjust the viewfinder for sharpness first. It is easier to adjust back focus when the subject is more than 3 meters from the camera. The optimal subject for this adjustment is a Siemens star chart.
1. Set the IRIS mode switch to M (Manual). 2. Set the zoom mode to MANU (Manual). 3. Open the iris ring. If the illumination is too strong, reduce it
or move to a darker place.
4. Turn the zoom lever until the lens is at the maximum
7. 8. 10.
5. Bring the subject into focus. 6. Set the lens to maximum wide-angle. 7. Loosen the back focus ring retaining knob. 8. View the same subject and adjust the back focus ring for
the best possible focus.
9. Repeat steps 4. through 8. about three times for fine
adjustment until the subject remains in focus in both the telephoto position and the wide-angle position.
10.Tighten the back focus ring retaining knob to secure the
ring. Memo: ACCU FOCUS can also be used in the above step 3.