Hi Howard and Kelly, I like you have inherited a PFAFF 1475 CD and have no idea what the 3 letter code is. I realize you posted your message quite a while ago. Did you ever find a solution to the code. Both the suggestions from the reply to your post did not work for me and I have tried every possible code I thought my sister would have entered into her machine. Any help you can provide would be greatly appreciated. Thanks for your help. If you receive this please email me your response to snipped-for-privacy@gmail.com. Thanks for your help. Regards, Tina