@SilviuZ Sorry your Duet has failed. Were you were wiring the fan up with VIN power on? We advise not to do such wiring with power on for just this reason. Unfortunately it sounds like you shorted 12 or 24V to 3.3V, and it’s caused a failure of the processor. There’s very little that can be done, unless you have access to hot air SMT reflow tools, as you’d need to replace the processor for a start, and possibly a number of other components. It will quickly become uneconomical to repair if you cannot do it yourself.
The warranty for official Duet boards (as opposed to clones) is for 6 months, and does not cover failures of the board due to user error; see https://www.duet3d.com/warranty
However, if you contact sales@duet3d.com, we have a small stock of refurbished Duets that may reduce the cost of replacement.
Ian
