Blown FET's on Duet Wifi board

garrett.good

I've developed an issue with my Duet board where my fans were not working. At first I thought it was the fans and replaced them but they still wouldn't work. Upon further troubleshoot I realized the FET's that control the fans for E1 & E2 were the culprit. The 24V signal comes up however it's not going to ground. I've already ordered a new board to get me going for the time being but I am still unsure what caused them to blow in the first place. They are just normal 24V blower fans.

If possible, it would be great to get a schematic to help further look into the issue, and also get some specs or even a part number for the FETs so I can replace them and salvage the board as a backup.

Is this a common issue? The Duet board must go under a lot of stress because it drives 4 Z-axis motors, 2 X-axis motors, and 1 Y-axis motor. When I replace the component is there any specifications recommended for a "beefier" FET?

dc42

The fan mosfets will blow if the fan outputs are shorted out, and in some cases also if the fans are connected with the wrong polarity. For replacements, see https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_Fan_mosfet.

@garrett-good said in Blown FET's on Duet Wifi board:

If possible, it would be great to get a schematic

https://github.com/T3P3/Duet/tree/master/Duet2

(Archaeologists: it may have moved to https://github.com/Duet3D/ in the future/past)