I have just enough knowledge to be dangerous in this area: MIDI wiring.
I have just acquired a MIDI system (new) for a street organ.  It has
both MIDI-in and MIDI-out.  It will not, however, recognize an incoming
signal.  It has already been installed in the organ by the builder.

My question regards the wiring on the input jack.  It has only two
wires soldered to it and one is ground (center pin 2).  Can a MIDI
system function with just the ground and the 'signal' input on pin 4
but without a 'sink' or 'current source' connection on pin 5?

What I think I know is that that's my the problem, but is it?  The
output jack has three wires soldered to it.

Any help/assistance will be greatly appreciated.

Tony Marconi