On Wed, 26 Feb 2020, Barry Hills wrote:
  I sold the heads separately along with a set of
replacement cards and
 the remote display for $400. 
You did what???
Did you really "ruin" an apparently intact drum instead of keeping it
complete as one piece?
  Anybody know what non-magnetic metal forms the drum?
Stainless?  Nickel? 
Most probably aluminium.
Christian