Lone in the night

I have a Atari STe with a Soundpool MO4 MIDI extension. It used to work very well, but unfortunatelly doesn't anymore: Cubase still detects it, and I can output MIDI to it but nothing is coming out from any MIDI Out. It took me a while to tackle it (lack of time, lack of tool, other items to play with), but I gave a glance last week-end. The parallel port on the Atari uses only the following signals: Pin 1 : Strobe (Atari -> MO4) Pin 2 : Data 0 (Atari -> MO4) Pin 3 : Data 1 (Atari -> MO4) Pin 4 : Data 2 (Atari -> MO4) Pin 5 : Data 3 (Atari -> MO4) Pin 6 : Data 4 (Atari -> MO4) Pin 7 : Data 5 (Atari -> MO4) Pin 8 : Data 6 (Atari -> MO4) Pin 9 : Data 7 (Atari -> MO4) Pin 11: Busy (MO4 -> Atari) The MO4 also decodes few other pins, but since the Atari doesn't, my guess is the MO4 was also targeted for PC. Inside the box, the MO4 is architectured around a CPLD (IspLSI1016 from Lattice) which contains the logi...