When I boot the Flsun Cube F5 with an MKS Gen L v1.0 controller board, it boots fine; it beeps, and all the LEDs come on. When I heat the hotend it works beautifully, and once up to temperature, the extruder motor feeds just like it should.

However, when I turn on the heater of the build plate, it starts heating and after about 10-12 seconds the board, specifically the MOSFET at the heat bed connection quickly begins to get hot and starts to smoke. I feel if I let it continue, either the board would catch on fire or at least burn out the board.

Does anybody have any suggestions as to how to fix this? I still haven't tried the X, Y, and Z steppers yet, but that will be coming soon.

  • 1
    $\begingroup$ Dear Brian, if you are referring to this previous question, please add an answer or delete the question (preferably answer your question and accept the answer after 48 hours). It might be beneficial to other with similar problems! Thanks. $\endgroup$
    – 0scar
    Jul 22 at 9:58

1 Answer 1


The MOSFET is either dead, or can't handle the high current the bed requires. You can try using an external MOSFET which is quite easy to wire, or alternatively soldering a new MOSFET one which is quite difficult.

Example of an external MOSFET (module):

enter image description here


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