These cards are compatible with only Thunderbolt 2 or 3 PCIe expansion chassis; they are not compatible with Thunderbolt 1 PCIe expansion chassis (unless they have been upgraded to Thunderbolt 2).
All current and recent Sonnet USB 3 cards have resettable fuses to protect the ports from an overcurrent condition. To reset the fuses, you must remove power to the card by shutting down your machine. (Restarting is not sufficient.) After turning the computer back on, the ports should start working again. If the fuses continue to trip, then you may have a device that draws too much USB Bus power (more than 2 Amps).
