Prusa I3 M201 Fan speed

[Juliemac]

I printed something today and noticed the fans had stopped. The just bobbed back and forth. The 12v to the fans had dropped to 3v after the first spin up.
This includes all the fans. The extruder fans, the heater fan as well as the Control Board cooling fan.
I cannot find a schematic to find what drives the fans, where the power comes from etc.

Any one else had this problem?

[Juliemac]

I found the 5v on the driver chips also drops in voltage...
So whare is this PS on board?