Re: MIDI keyboard fault
As mentioned previously, if you are trying to scope an otherwise unconnected MIDI output you will need to supply a load resistor because the output is open-collector. See the attached image, taken from 'Advanced Midi User's Guide' (R.A. Penfold, 1991).
Wire a resistor (about 220R to 470R) between pins 4 and 5 on a spare 180 degree five pin DIN plug, plug it into MIDI OUT on the keyboard and use the scope to monitor what's coming out on pin 5.
To generate a long stream of MIDI info rather than just a quick 'blurt' every time you press or release a note, try rolling the pitch wheel smoothly back and forward. You won't be able to 'read' the individual packets but you will be able to see if the data is clean and square.
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