I got 3 C4. Based on the page's spec, they are supposed to handle 15.5V, so I used a 15V power supply from odroid.
Initially everything was fine, but when I added EMMCs cards and plugged them back one odroid released some magic smoke around the Ethernet connector. All 3 also doesn't have anymore the red LED light fully up.
I also had the 3 LCD shild plug-in, and the 3 doesn't light up anymore. The 8 leds on them are fine through.
I checked the voltage of the power supply, who is around 15.05V, so in spec. This should not have destroy the C4s.
What should I do ?

Thanks and have a nice day,