I've received the DAC+ADC this week and was trying to use it today. I had a brand new install of Raspbian with the latest updates. My Pi cannot seem to see the board at all. Are there any LED's on the board that should light to tell me that it is working? I've sen nothing. I've tried it on a 2b and a 3a+ but on neither of them did I get any sign off life. Is there any more I can do to check? I don't want to send it back to Farnell if it's user error on my part, but listing the inputs and outputs it never shows up.