An acquaintance has a 10-year-old Hofbauer 37-note crank organ that
plays from proprietary memory cartridges through its own electronics,
which drive electromagnetic valves.  Some of the Hofbauer music
cartridges are not playing properly, and he would like to expand his
repertoire beyond the limits of Hofbauer's music library.

Some questions:

1. Is it possible to feed MIDI serial music into a Hofbauer organ
(from a separate MIDI player source)?  If so, is some conversion work
necessary?  If so, would the original Hofbauer functions still work?
Can the MIDI circuit be wired in parallel with the Hofbauer circuit
board, so both can co-exist?

I built a complete MIDI interface into my Raffin 31er, from scratch,
but didn't have to fight any existing electronics.

2. Some Hofbauer memory cartridges play only half the tunes on them,
while others play all the tunes okay.  Does this mean the half-playing
cartridges are faulty, or does this point to dirty contacts where they
plug into the circuit panel?  Or some other interface fault?

3. Long shot: Has anyone figured out how to "burn" a MIDI file into
a memory card that can be plugged into the Hofbauer like the factory
cartridges?

By the way, this owner has just replaced the lead-acid batteries that
power the organ, and the control panel indicates that the batteries
are properly  charged.  Thanks for any ideas.

Mike Knudsen

 [ See http://mmd.foxtail.com/Archives/KWIC/H/hofbauer.html
 [ -- Robbie