Is your build feeling ill? It’s probably something simple:

• Do you have the jumpers set up correctly for your firmware?
• Are your socketed ICs in their proper sockets and oriented the right way around?
• Are you providing the board with 9v DC power with center pin positive?
  • You can use a 9v battery if you don’t trust your power supply.
  • If you have an Arduino board, you can also provide power directly by connecting  jumpers from the Arduino’s 5v out and GND out to the corresponding pads on the header here (NB. Don’t connect 9v here!):  
• Did you remember to solder in the permanent jumpers for the on/off switch and volume pot?
• Check the orientation of all your soldered ICs.
• Turn your board over and go over it carefully to make sure everything is soldered properly – I’ve torn my hair out because I forgot to solder one side’s legs on a 595. Very weird results!

(Encountered an issue in your build? Give me a shout and I’ll gladly add it here for the benefit of future builders.)