EVERYTHING, since I received this machine. The "INSTRUCTIONAL MANUAL" looks more like a "UNITED NATIONS RESOLUTION" in all different languages. My pressure foot is way to hard to lift and YES I turned the knob on top. My bobbin won't feed out. all I did was to switch bobbin color? Oh, I almost forgot to add that the knee pad never worked, just to many problems and no booklet to fix them.

I am attaching two links for manuals in case you don't have them, an instructional manual and a service (repair manual). The Singer 500 and 500A are the same machine.
Singer 500 Owners manual

Singer 500 503 Service Manual

The free one came in the box with the machine, a replacement can be ordered...
PFAFF Model GrandQuilter 18 8 Users Instruction Manual PFAFF Model...

Go to Singer. Com and type in your model number they provide a free manual download and it provides pictures of what you're after.

Need an instructional manual English for janome memoria 5002

You may download a copy of the manual at Owners Manual User Guide for Singer 7444 Mechanical Sewing Machine

Approach the store where you bought it to order replacement

I also have a Juki DNU-1541S and I'v had nothing but problems. My bobbin will not feed out thread. The Pressure foot needs a wrench to lift it, the knee pad will not work due to the pressure foot being so stiff. YES, I've turned the knob at the top so much it's near comming off !!
The so-called "Instructional Manual" appears to be a "UNITED NATIONS" resolution in all languages. The English portions is barely enough to fit 1/4 page. A Manual ?? A JOKE is better.

Google Tias, relics and see if they have it. They usually have alot of old manual reprints that you can purchase

Hi I hope this helps. These are United States contacts. Thank's, Jeff http://www.juki.com/contacts.html

have you had any luck? I need one too!