I've been reading this thread with some interest, I suppose because
I have spent a lot of time in casual research and development of
electromechanical devices over the years.  I'd be glad to lend such
help as is appropriate, but I'll need to know a few things:

1. What is a PowerRoll, i.e., what does it do?
2. How is the current version constructed?
3. What are the specific technical difficulties in the
   current version of the device?

From what I've read about the original designer of the circuit board
having passed away and the repeated difficulties of the current
developer in constructing a reliable device, my sense is that the
developer is not inherently proficient in electronics design.

If this is indeed the case, any design flaw in the circuit board would
remain an ongoing mystery to the developer, especially if it was a
parts rating issue that causes intermittent failures in other
components.

I know that there are several subscribers to this newsletter who are
exceedingly proficient in electronics work, and it's quite possible
that a limited distribution of the device's schematic (complete with
parts ratings) will yield some solutions.

There's no shame in _not_ being inherently electronics-wise -- it's the
sort of aptitude that you're born with.  I was not: though I've taught
the subject for a number of years, I always have to go through and
learn it again.  (Some of my students, however, have become marvelous
designers after I taught them the various relationships and thought
processes.  Go figure.)

Mark Kinsler
Lancaster, Ohio USA
http://www.frognet.net/~kinsler

 [ The PowerRoll is a small thin box, containing 100 tiny electric cup
 [ magnet valves, which is placed over the tracker bar as a substitute
 [ for the paper music roll.  It's very compact, 5" x 11.75" x 2.25",
 [ designed to fit entirely within the music roll transport frame
 [ inside the drawer of an Ampico piano.  The valves and all electronic
 [ components are mounted upon a multi-layer printed circuit card
 [ assembly which also routes the air from the valves to the tracker
 [ bar holes.
 [
 [ As I understand the problem, in some situations the device can
 [ become hot enough so that the adhesive, which secures the valve
 [ components to the circuit card assembly, slowly migrates after
 [ a while and causes valve troubles.  I believe the electronic
 [ problems were solved long ago.  -- Robbie