Hi guys, I'm building a midi-controller and this is a board with multiplexers and pin out the other another board. I'm being suspicious about VCC and ground.. I have taken a simultation on both boards and they ended up bad. But I have used NetVCC and NetGround... Pardon my naive knowledge. 1. **Arduino Uno board shield for multiplexers** [https://easyeda\.com/editor\#id=\|4d43712118db414aa9c40491498475f3\|e37cad6ee3144000a15617c24be98f7d](https://easyeda.com/editor#id=|4d43712118db414aa9c40491498475f3|e37cad6ee3144000a15617c24be98f7d) Simulation: Warning: singular matrix:  check nodes vcc and vcc 2. **Board for Pot and Buttons**.. [https://easyeda.com/yalexein/potbuttonjoystickshield](https://easyeda.com/yalexein/potbuttonjoystickshield) Simulation: Warning: singular matrix:  check nodes vcc and vcc I have no PCB experience at all and I don't have studied electronics. Someone can give a hint on the project? Thanks to all.