I recently found a solution (I think) to a problem I've been having
with my PianoDisc 128+.  Thus unit has a "Pass Through" mode which
permits me to play MIDI files directly from my PC through a MIDI
interface.  In my case, the MIDI interface is plugged into the sound
card using the joystick port.

I call the problem "the drunken piano player" (hereinafter "DPP").
Usually the piano would play perfectly, but sometimes it began to sound
like the piano player had 'had a few too many' -- errant notes, missed
notes, garbled chords, rhythm problems, etc.  The only way to fix the
problem was to turn off and unplug and re-power the PD.  Then it would
work fine again.  I tried a serial port MIDI interface and the problem
continued, although this time DPP's errors were more glaring.

The folks at PianoDisc were concerned and helpful, and finally sent a
new PianoDisc unit.  Same problem, but at least I now knew that it
wasn't the PD.  So I borrowed a friend's laptop, loaded some MIDI
software, and tried it for hours.  No DPP.  I took the laptop to the
dealer and tried it on a unit in the showroom for 1-1/2 hours.  No DPP.
I got my old unit back from the dealer and reconnected it.  No DPP.

So I thought about the differences between the Pentium 133 laptop and
my Pentium 150 PC and concluded that one difference was that the
laptop, being battery operated, had a consistent power supply.  On the
other hand, my PC was plugged into the wall in my apartment, which is a
loft in an old, converted furniture warehouse in downtown Milwaukee WI,
and probably did not have a consistent power supply.

So I bought an uninterruptable power source ("UPS"), which has a
battery backup, line conditioner and surge protector.  I plugged the
PC into it and this _seems_ to have eradicated the DPI.   I invite
anyone's diagnosis of what the original problem was, as well as any
other possible solutions.

But I have one question.  I want to plug both the PC and the PianoDisc
into the UPS and I'm trying to figure out if the 400 VA UPS can handle
both the PC (excluding monitor, printer and such) and the PD.  The
PianoDisc User's Guide doesn't tell me how much power the PianoDisc
requires when all those solenoids are functioning.  Does anybody know
how many watts, or amps, or volt-amps a PDS-128 requires?

Thanks.

Mike Ryan