These are some links that you might find useful.

Many of them are in German!

Omars Pentacon Six Site

Japanese Site

Frank Cobergers excellent site

Users Group

This is Christian Senet's PraktisixIIA site.
 recomended vendors

Gary Camera Repair
228 Hett Avenue
Staten Island
NY 10306

Gary does good work and is inexpensive.

Leonid Treskunov
9A Poplar La.
Old Bridge
New Jersey 08857

Leonid is a little more expensive but does exqusite work. He repaired 2 Pentacons for me and they are better than the new cameras that I have. I can not say too much good about his work.

International Photodealer
180 Banjo Branch Road
Mars Hill,
North Carolina 28754

My prefered Pentacon Six Dealer dealer in the US.