I'm the character who bought the Dynavoice keytop piano player at the
Wabash rally mart.  A week later I got home and tried it out.  It's not
in bad shape: everything works except about six notes are stuck on due
to the nipples having broken off on the valve blocks.  I've read
through all the MMD Archive articles on the Dynavoice, and this seems
to be expected.  Also the playing is weak and not snappy.

Mine is a Model PL51, serial #2150, with the transposing tracker bar,
valves in the roll tracking system (which looked like a 4-hole Simplex
but uses only one hole per side), and a triac circuit for continuous
control of the turbine motor.  The "Volume" knob is marked for three
loudness levels, but the knob rotates quite a ways on either side of
those.  Might the triac motor speed circuit be a retrofit?

The roll drive is impressive and solidly built: separate motors for
play and rewind, with the pinball machine type of self-disengaging
armature on the play motor.

The tracker bar tubing is a whitish transparent, very narrow type,
sized just right for the tracker bar holes, and not the clear plastic
"aquarium" stuff we all hate.  Even the unit valve block design, based
on water-softener and washing-machine servos, is ingenious plastics
engineering (except for those under-designed nipples!).

There's one extreme treble pneumatic unit with no striker or tracker
bar tube, just open to the air, with a microswitch.  It seems to be
intended to throw the switch when vacuum is attained.  Maybe it shorts
out the speed-control triac when the unit is first getting up to speed,
and also if a big chord kills the vacuum.

The major complaint is that the unit isn't quite wide enough.  Instead
of perching on the wooden cheek blocks at each end of the keyboard, its
padded ends land on the last white key at each end, and squeeze against
the next key in also.  Is this correct?  Have piano keyboards shrunk
since my post-1925 Weber D-A grand was built?

 [ The Dynavoice rests upon the last white keys of the piano so that
 [ its height above the key tops, on any piano, is consistent.
 [ -- Robbie

Also I have to remove the fallboard key cover to get the unit far back
enough on the keys.  Maybe Duo-Art keys aren't quite full length front
to back; this has been discussed lately regarding Steinways.

The foam filter blocks above each valve outlet are turning to dust and
will have to be removed before they clog the workings.  All pouches,
valves, and pneumatics seem to be still flexible and working.

How can I repair the broken nipples?  Their inside diameter is so
narrow that even if I could find brass tubing thin enough to stick in
the hole, the inside diameter would be reduced to less than a tracker
bar opening, which would stifle the playing response.

There's no easy access to drill out the holes, due to other parts above
the valve blocks, and it's nearly impossible to remove the valve blocks
from the one-time clamp washers that hold them to the frame bottom.

I'm hoping that Tom Lear or Michael Stehney are still around and will
reveal their secrets of removing valve blocks from the frame.  And of
disassembling a valve block, though I don't know that it will be
necessary except to reduce the valve travel and save air and speed up
repetition.  Tom, if you're out there, I'm the one who inspired you to
try a conventional bellows-type electric pump on your Dynavoice (maybe
I shouldn't admit that, depending how it turned out.  :-)

I wish there were some way to stop rewinding once it's started, to
save the roll or just to go back and play some part over.  But the
mechanical flip-flop arrangement between the rewind pneumatic and the
roll feeler on the take-up spool won't allow for that.  Any ideas?

Well, my main concerns are repairing the nipples and making the unit
fit on my piano keyboard, then getting the suction up to par.  Thanks
in advance.

Mike Knudsen