Dear MMDers,  Could someone explain to me, please, why my Weber upright
pianola strikes repeatedly on certain 'held' notes represented by chain
perforations on the roll?

Is this the fault of the roll or the instrument and what, if anything,
can I do about it as it spoils the otherwise enjoyable rolls.  All
advice gratefully received.

Jim Spriggs, (Old) York, UK

 [ It might be due to porous valve pouches.  -- Robbie