Elation Sixpar 100 are starting to fail.

We have 8 sixpar 100 lights, we had one stop communicating with the coloursource 20 we moved the light to another spot on the rig and it started working for a couple of days then stopped again. Now there's another light not working. is this a problem with the circuit board in the light or is there a problem with the 3.1 version for the coloursource 20?