I found a Solution!
I found a hint in another related topic and it's about a Paper clip switch and it WORKs!! I really can't understand why but it does. This is what I did: As usual I would turn on the Ax1200i and seconds later an audible sound followed by the red self-test light and everything would be powered off. Following the suggestion I took some pliers, removed the paper clip and re-inserted it and… Eureka!
I now have 3 overclocked cubes on my AX1200i working with a silence never before experienced.
Hope it helps you too
That is an odd solution lol