Here are a few shops that specialize in antique phonograph repair, which you could contact about some of the missing parts:
Great Lakes Antique Phonograph --
http://www.victroladoctor.com/ -- The people there are VERY helpful.
Victrola Repair Service --
http://www.victrolarepairservice.com/The Antique Phonograph Supply Company --
http://www.antiquephono.com/Shenandoah Antique Phonograph Repair --
http://www.shenandoahrestoration.com/phono.htmlJohn Lewis's Mechanical Antiques Repair --
http://www.antiquephonograph.com/They would also be helpful should you decide to have the motor professionally cleaned and re-greased. If you are a do it yourself type person, you might consider investing in a book called "The Compleat Talking Machine," by Eric Reiss. It is well illustrated and walks you through, step by step, most repairs or maintenance issues. If the springs need re-greasing, however, I'd suggest you have it done by one of the shops that specialize in this.
FYI, here's a generic type Sonora phonograph manual, with the basic operation and maintenance instructions --
http://www.nipperhead.com/old/sonora.htm Just click on the thumbnail images to make them full size for viewing or printing. Along this line, reproduction manuals for a variety of models come up for sale on sites such as ebay, from time to time. You might even find one specific to your model.
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If you want to do any cabinet refinishing, keep in mind that the original finish matched the inside of the lid and doors. It's generally referred to as a piano style finish--high gloss, but not the "wet look" you see on some modern furniture. This was done by applying several layers of clear shellac over the stained mahogany. (Woodgrain filler was also used on the veneer, itself.)
Most collectors today prefer to do a minimalist type of restoration. Since this is over 90 years old, in other words, the feeling is, it shouldn't look brand new. For this reason, many recommend that you use a good quality cabinet cleaner and restorer such as "Howard's Restore a Finish" --
http://www.howardproducts.com/prod-restor-a-finish.php This is now available at most hardware stores, and you use it according to the instructions on the can. It's a good idea to use very, very fine steel wool to apply it.
Another option, of course, if there are deep scratches, would be to have it professionally re-done, but only as a last resort, and the person or shop should have experience working with something from this era. Normally, this exceeds the "current average market value" of the phonograph, which for this model, would be around $300-$500 if it's in very good, original condition.
HTH,
Joe