Has anyone had this issue:

I changed voltages like always (running my miners from 1000-1300Ghs). The miner hung up. When I tried to reboot, it didnt start anymore. One of the 4 PCIe sockets seems damages. As soon as I pull out the cable of this one, the miner will boot and mine with 3 of 4 asics, 75% power. As soon as I provide the 4th socket with a cable again, the miner wont boot.

I cant figure out, where the problem is and what I can do.. It cant be that a part of the miner "burns" when switching voltages lower?? As stated, I never pushed them higher than 1300 or lower than 1000.