Check Ribbon Cables
Check Power Cables
If your USB reader is not reading properly, you might check the power and ribbon cables.
The power cable typically has a notch in it to ensure its not plugged in backward. The positive power cable, which is typically red, should be plugged into the pin closest to the ribbon cable.
The ribbon cable should be plugged in with the red pin #1 closest to power cable.
Be sure your equipment or machine is completely powered off when disconnecting or connecting cables.