Midipal help no midi input !?

Hello Mutable Instruments users

I have just finished to build my wonderful Midipal :slight_smile: BUT I dont have any midi input message comming in,

the red led is not blinkin & no data is viewed in the midi monitor
the 2 led is working when I reset the device and also the sequencer is outputing data, I am not able to use any of the app with midi input e.g arp chord memory ect…

Would like to mention that I have only test it with a 9v battery.

Any help will be appreciated

Best regards,


Hey guys

Thank you all for the support! It is working correctly, the problem was indeed the diode that was not solder the right way :slight_smile:

Best regards from Montreal


Which voltage do you have at pin 6 of the optocoupler, at rest and when sending a dense MIDI stream? If you have a scope you should see logic pulse (+3.3V at rest) for the MIDI messages.

Check the diode is the right way around and the resistors are the correct values in the MIDI in area.