Hello, my name is Michael.
A Specialized Antique Shops will have the type of information you are requesting and as they restore and resell selected equipment as the one you have, many of those places would have the original service manuals that are not found online yet.
you can get a copy of the manual at the following page, but they charge for sending it. I suggested the alternatives because they would be very likely at no charge if you're able to get it through them. you had not indicated that you tried anything in your original information so I had no way of knowing what you have already tried. I hope this more completely answers your question.