Very late to this, but if anyone is looking, there are FB groups that have many manuals for the vintage sewing machines in their group files.
There is a service manual for this machine, we have it in Vintage Sewing Machines group on FB, 37,000 member group.
Melanie
June 2017
Jack, thank you so much! This is a very comprehensive manual
Kaz
March 2010
Go to www.tfsr.org On the home page you will find a Sewing Machine Manual in sections covering 15k, 66, 99 & 201 machines which has been produced for our volunteers refurbishing machines to send to Africa. It is free to use, but we would always appreciate a donation if you like what you see.
Hello Krystyna,
Decauls for the 66 will be very difficult to get, you will have to search far and wide, a service manual for the 66 I don't think exists, I can never remember one being printed but if you e-mail me below I will attach a list of sites.
To put the bobbin case in make sure the take up lever is at the top, move the catch to the right and you should be able to slide the bobbin case in quite easily.
Ken
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix sewing machines.