Here are the cleaning tutorials
Part 1:
http://www.quiltingboard.com/t-45816-1.htm
Part 2:
http://www.quiltingboard.com/t-45983-1.htm
Part 3:
http://www.quiltingboard.com/t-46696-1.htm
Furniture cleaning:
http://www.quiltingboard.com/t-133115-1.htm
And one to check the wires first:
http://www.quiltingboard.com/t-45814-1.htm
You can also call Singer 800-474-6437 and ask them if they can give you a model and date of your machine. Although I think I have read before that some of the records from Germany are lost.
Good luck!