If the issue were power supply related I'd be fairly shocked. Almost 100% of the issues I've seen that have symptoms like you describe are link cable related. Which link cable are y'all using?

I am having this same problem. The Arduinoboy LEDs light up when I send MIDI to it on channel 1-5, but won't send those notes to mGB on my DMG-01. I have tested LSDJ in Slave and Master sync modes and both are working... I don't know where the problem lies, but Matt from Kitsch Bent keeps telling me he thinks I have a power supply with the wrong polarity going to the Arduinoboy... I'm going to be buying a new power supply to test with it, though the one I have seems like it should be compatible already (positive center pin, 9V, plenty of mA)

Greetings,

So, I have an arduinoboy that appears to be "working." However, when I try to use mGB, the arduinoboy recognizes my MIDI notes (LED flashes), but it does not trigger the DMG (no sound comes out). I am using MIDI channel 1.

Also, when I try to use LSDJ keyboard mode, the arduinoboy recognizes the notes, but once again it does not communicate with the DMG properly. When in keyboard sync, playing a E or D-sharp cause a letter "M" to appear on the right side of the screen. It does not play any notes. I am using MIDI channel 16.

I also tried both set-ups with an GBA SP. Does anybody have experience with issues of this sort. I have gotten the LSDJ to work with an LSDJMC2.

Thanks