When running my DIY CNC Router, everything seems to run OK, until I turn on the Router. Then movements are jerky. For example: Code says G0 X10 Y6, but machine makes several short movements to go there. Position seems correct at end of movement. I was thinking electrical noise. I moved router power to a different circuit and frequency of interruptions went down but are still there .After I started thread, I found that the USB connection was intermittent, but changing cables did nothing. Is my problem more likely Electrical noise, or vibration shaking a connection on the board lose?