I have twice tried to solder together a MIDI-out adaptor for my Roland LAPC-I using the MCB-1 schematic that circulates on this forum.

However both times the adaptors I made don't work, despite using components from different batches each time and double checking that the pinout of the DB15 and DIN connectors are correct. I connect the adaptor to the DB15 of the LAPC-I and start a game, but the LAPC-I only plays MIDI using it's internal synth and nothing happens at the display screen of the MT-32 I have connected to the MIDI-out DIN of the adaptor. The adaptor gets 5 volts from the LAPC-I, but I don't know if it receives any MIDI data.

It's possible that I fried the port of my LAPC-I during my early attempts at making the adaptor when I got the pinout wrong, but has anyone else succeeded in making a working adaptor from the schematics so I know if it's possible?