Small fan quit right after the hotend clogged.

S/N: KT-PR0017NA-8587
Date completed: 2/11/15
Jerod Ernst

Today i started a print, watched to make sure it got the brim down. Then went to have a smoke, when i came back to check on it i saw that it was no longer extruding. Killed the power right away. Restarted and heated it back up to see if the hobbled bolt had taken a bite out of it. It was hard to see and then i saw a ton of little plastic shavings. Tried to pull the filament out and could not. Turned it back off and visited the forum to see if i could find an answer. Found a post where it seemed to have my answer that i needed. ( In there Orias listed a step by step way to fix the issue. I’ll rehash as short as i can.

  1. Heated the hotend using pronterface to 250c, then waited a while for it the heat up then a extra min or two.
  2. Popped open the idler holder.
  3. Tried to tug the filament out. No luck, so i let it set for a couple more min to see if it would soften up so i could tug it out. Once again i gave it a tug and it broke off from the hotend.
  4. went back to the forum to see if i could find help, nothing really that i could tell.
  5. Called a buddy that had a jeweler’s lathe thing, and asked for some help cuz he had very fine bits. Worked with him for a couple hours to trim out filament that we could see before putting the whole thing back together.
  6. Heated the end up and fed some filament in, boom had feed, crappy but feed. Then i noticed that the small fan was not working. Thinking that i may have got the wires wrong i shut it off and pulled my book. (which by the way as a side note, it don’t really show a way to tell the 2 fan plugs apart. Update maybe.) Since it was not working i unplugged the 2 and switched them. Still got nothing, again i turned it off and checked my wiring and inside the plugs to see if when i took it apart, if something worked loose. didn’t find anything so i restarted it. Nope nothing.
    after troubleshooting by unpluging the small fan and plugging it into the large fan which is working, it still does not work.

So where do i go from here, do i have to pay for a whole new head or is it covered. It really seems that the wiring is not putting out power to turn it on at all.

I’m having the same issue it started to print I’m happy I step out and came back to see that the filament stop feeding. I took the print head apart n drop the hex head (I’m not sure the proper name) after the feeder to see a hard clogged enterace. I clean it out started again to come back to the same issue. The small fan dose not turn on at all so I’m wondering if the heats is traveling up and causing the clog or if the temperature and or speed is incorrect. Please help

The small blower fan should be on when the printer is on. If it isn’t running when the printer is printing, you’ll get a jam. If your fan isn’t working, contact



thanks i emailed them, waiting on a reply.

Yay lulzbot is sending a replacement fan.

For your guys info, theres a blue mark on the little fans connector that clips onto the wire harness that should have a blue mark too.

On mine, it seems one 2pin plug has marks… and the other doesn’t. I think in the quick start they mention this… but not in detail.

Its good that lulzbot has top notch support, but sounds like I need to pick up a spare blower or two. :slight_smile: Well… I guess I’ll have to pick them up when available on the website. They look really difficult to source individually.

Oh believe me they are, the one company that seems to have them that i can find, quoted me 28 bucks for one. And 15 days to ship if lucky.

I may make a mod to use a different 5v fan. ill post it after i do a few runs if i get some time.

That’s what I was thinking also… a quick fan duct for a 5V box fan.

We have modified the “dot” on the housings to make it more prominent/obvious which goes to which. It will be on all four housings. They really should be keyed.

I apologize for any inconvenience,


You should be able to find existing ones out there, they just use a “regular” square fan. I think reprapdiscount may have a version.

Its np. mistakes happen, really happy to have great feedback. and ill check that link out, what i had in mind was a (printer head insert?) or mod that uses 3 fans. Left, right and front that weights the same but gives you greater control over how much air is used where. a buddy had an idea to use a hose like thing with a flat nozzle to direct the air so less is hitting the bed.

LOving the printer BTW. :smiley:

Maybe those are wrong words, more like ill design a 3d printable item that i can use. then after i make sure it work share it.

OOOOOO @#$%, i give up, its just one of those days. :unamused: