Odd midi in behavior

I have ALMOST got my Shruthi working after having a friend take a look at it for me. I have a small problem though, I can’t seem to get the shruthi to respond to midi notes.

When on the browse pate screen, pressing notes on my midi master keyboard displays an odd symbol like an upside down “T” over a wide, shallow “U” in the top right rather than the musical note symbol. Moving the pitchwheel displays a “#” or a “!”. I have tried my midi keyboard with my sammich sid and it works fine. The Shruthi shows the same behavior with my PC midi out, any help much appreciated…

The MIDI input seems to receive garbled data. The “Upside down T” symbol is a pitch bend lever, the “!” and “#” are displayed when incorrect SysEx data is received. To troubleshoot this, you’ll need to scope the optocoupler output.

Thanks for pointing me in the right direction, I had a bad optocoupler!, just a bit of tuning to do and I am there.