My Wurlie drives me crazy !

[Don Tillman]

Hi Juergen!

A few quick possible suggestions...
  Dirt, dust or a dead insect might be shorting the pickup's high
  voltage to something.

  Check the high voltage supply on a 'scope, before that large value
  resistor, to make sure it's clean.  (I can imagine an aging capacitor
  causing some problems there.)

  Check all ground connections.  The description really sounds like a
  grounding problem.

On my Wurlie, an older model than yours, the loudest noise is the hiss
of the preamp.

  -- Don