Localize the problem by trying a second power supply. If the device works with a second supply, the first power supply is bad.
If the problem is with the power supply, it will need to be replaced. Power supplies can not be repaired.
How are your power supplies stored? It is possible to damage the power supply cable by winding the cable around the handle of the device. If the cord is wound tightly, it can pull the wires out of the strain relief and cause a malfunction.
Vernier AC Adapter (IPS) (For LabPro, CBL2, WDSS, and DCU.)
LabQuest Power Supply (LQ-PS)
How should I wrap my sensor cable?
My IPS AC Adapter does not power my LabPro, WDSS, or Stir Station.