Core Electronics Forum

Looking for WSK220N04 JG18K mosfet

Hello everyone,
I recently broke this mosfet trying to find the current draw on fan0 pin on the SKR v1. 4 board, how I achieved this I don’t know, but that is my talent.


My trouble shooting was that the fan on fan0 run at 100% and can’t be controlled, the heated bed goes to 100C and can’t be controlled and when I touched the Q2 mosfet it burnt my finger. I think I’m on the right track, is there anything else I should be checking and where would I get this misfit because I’m having trouble finding it online.

Thank you in advance

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Hi Thor,

I’ve found the datasheet for that MOSFET here:

Core don’t stock any N-Channel MOSFETs that are that beefy, if you get the specs from the datasheet though I’m sure you can find an equivalent in the same TO-263-2L package from a distributor like RS Components, Element 14, Mouser or Digikey.

I’m not too familiar with those control boards so I’m not sure what usually fails to get a thermal runaway like that happening. Perhaps someone else more familiar with the SKR boards has some ideas on what usually fails.

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Hi Thor
Are you sure this is “broken”. Quite often this centre pin is connected to the large metal back of the device which is soldered to a big chunk of copper track to assist in heat dissipation. This is then the same connection as the centre pin which is cut off or just not there.
Cheers Bob

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Thank you for the replies,
I had a second board that also stopped working for a different reason, so I thought I would swap the mosfets. When I was doing that I found this little doo-ma-hockey was discoloured so I scratched it with my nail and the resine broke off, so I’m thinking this may be the issue as its connected to the fan I couldn’t control.
I think I’ll try swapping that as well.

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Hi Trent,
Sorry for the rely slow reply. I finaly had 10 minutes to sit down and test it and cooked it good and proper. O have sorted open the main fan and heat in the open possion, so Ive cut my losses and got a MKS GEN L 2.1 and external mosfets.