I bought a MD313 (2011 MacBook pro 13" i5) MacBook pro this summer. But after connecting my [USB] fan, the port only works with the fan. When I plug one USB, no signal connection. For 1 external hard drive, there is only noise in the motor drive and the light flashes, by contrast on the mac, nothing is displayed, as if I have nothing connected.
I tried to alt Cmd PR but nothing has changed
Could you advise me how to solve this problem please?
Thank you in advance for your answers.