This is going to be a long one but I could really use your help. Alright, so my makerbot replicator 2’s extruder fan stopped spinning about 6 months ago. I was trying to load wood filament when I noticed smoke starting to come out of the extruder. I immediately turned off the printer and pulled out the filament. I took apart the extruder assembly to see if anything was broken but I didn’t find anything wrong. The next time I turned it on the extruder fan wouldn’t start spinning. I bought multiple different 12v fans to try (Some of which being the expensive ones makerbot sells themselves) but none of them have worked. I used a multimeter to see if any electricity was coming through the wires and it was. I was getting about 16-18 volts which should be more than enough to spin up a 12v fan but I also tried 24v fans which also didn’t work. I ended up figured out that as soon as a fan was connected, the voltage dropped to 0 volts, almost as if the fan was trying to draw so much current that the printer cut the power to it. I have no idea what else it could be other than something in the circuit board but replacements cost over $100 and i’d like to know if any of you have a solution. Thanks!

Its most likely the FET’s that control the fans, i repair a lot of these.

Yes, the mosfets are not current rated high enough. Seems like a duplicate issue as this guy:

There is a direct replacement available thats rated for 3 amps, thats what i put on all the boards that i repair now, a really quick repair, hot air rework remove and replace and test.

If you need one fixed let me know, i have reasonable rates and always have parts in stock for these boards, i repair Rev E, Rev G, and Rev H, i do everything from complete rebuilds on these boards to testing, they don’t leave my shop without being fully repaired and print tested for 6-8 hours.