Are there any affordable open source projects in the opposite direction?

I’ve built a rather complex robot with Nema steppers. Now something is messing with the control board and causing the CPU to glitch. Physically apart from the robot, the CPU board works fine for weeks. It also has a completely separate power circuit with optocouplers. So my guess is that it might be the power supply or one of the motors emitting electromagnetic interference. But how would I measure that?