I have found the source of this coat-of-arms!
The so called "Lehndorff'sche Wappenbuch" (MS. in the Bibl. der K. Deutschen Gesellschaft in Koenigsberg), p. 49. My picture comes from the 19th century version of "Siebmacher Wappenbuch". I would love to see the original picture!!!
"auf Weiß eine schwarze Faßleiter"
– the book probably didn't survive the war... I have read about it in G. A. Mülverstedt. Maybe you have more information about this "Lehndorff'sche Wappenbuch"?