http://ussrphoto.com/Wiki/default.asp?WikiCatID=98&ParentID=1&ContentID=1035&Item=FED+1b+%2D+Unusual+Serial+NumbersHere is the listing of our wiki:
220 - AVITO 2012 /att. 10/I/1937/ lens #35071
280 - DVD Tech
377 - A.Nikitin
417 - Bill Parkinson
420 - S.Pseunok
568 - internet
852 - A.Nikitin
1032 - Aidas Pikiotas
1126 - Jacques M. (1b between c. 11500-21000)
1151 - Molotok
1653 - seen on Molotok
1705 - DVD Tech
2013 - PYC (Fed-S 1c)
2532 - photohistory
2969 - Halsey, Nikitin (Lens #34959) /zinc/
3504 - Collector in Kharkov (passport 20/VIII/1936 see photo / Lens #44236)
3631 - Bill Parkinson, Jacques M.
3909 - DVD Tech (FED-S 1c)
4573 - ebay. Narrow engraving.
4580 - Jacques M. (1b brown vulcanite, large engraving)
4586 - DVD Tech (FED-S & B ? 1d)
4875 - James McGee
5298 - Alexander K. (Lens #5977)
5378 - A.Nikitin ( Fed S)
5664 - DVD Tech
5957 - web (lens 1\2 #6823)
25726 - Jacques M. (Fed S 1d)
25949 - DVD Tech (Fed-S 1c)
32580 - Mike Haley (napchop)
27839 - Avto Metreveli
Two groups in this list, by the s/n: cameras which belong to the 1a series (202 to 5957) and four with a 1b serial number. The idea that many 1a-s were not correctly working, so repaired or changed under warrantee, is clear. But the wiki does not give enough information about the conversion of these cameras. If the owners could share... I will do my best with my other three cameras.
Jacques.