The only thing that occurs is that this is the same initial sound of the startup but in a loop. I don’t know either if it’s normal, but it was always like that (from April 2014).
the same sound does my cpu cooler fan when it needs maintenance and cleaning and I see a lot of debris inside your printer. Take out the bottom plate of the printer and look if the fan in your mainboard works ok if not give it a clean and some lubrication.
No, not the fans. Sure, there are a lot of debris but not inside fans, I'm not that insane, at lest not yet.
I fixed it. Was the PSU, a weird relay inside the PSU. What is funny is that this behavior was present since the beginning of the times, since I bought M200 in February 2014.
But as my first 3D printer, I thought it was normal... Only with sleep mode, present in the last firmware, this sound entered in loop, screaming that it isn't normal.