Extruder fan stopped working, ruined extruder. How to fix?  

Re: Extruder fan stopped working, ruined extruder. How to fix?

Depends how bad the clog is. I am assuming that you got a hotend thats clogged from the inside.

Note: take the following steps at your own risk, this is what I would do, but not guarantees

I guess my first attempt would be: undo the 2 screws at the idler and flip it open, heat up the nozzle to print temp, maybe a bit higher (+5-10%) , wait till the desired temp is reached and then give it an extra 5 minutes or so for heat to spread and things soften a bit. Move the extruder up and to one side (don't leave it in the middle, rods bend easier if its in the middle)

Try to pull as much filament out as possible. Don't mess with the ptfe tube at the entrance to the hotend too much, if it gets chewed up, you'll have issues loading filament later. Use some fresh filament and try to push it down the hole to the hotend (don't feed it trough the top hole, just go in from the side). With luck, you can push it through and the bloackage goes away. If not, try poking through the nozzle with the supplied acupuncture needled. If you're brave you could try poking with a 1,5mm allen wrench from the other end as well. If you're lucky, this can help losen the blockage and allowing you to push new filament through. (Don't forget to do a bunch of cold pulls when done to get it even cleaner)

Most likely it won't clear it. The few times i ended up with a clogged hotend due to fan failure it was a royal mess..

So it's probably time to dismantle the hotend.

Check the Prusa build manual how it was put together and take the steps in reverse. Depending where the blockage sits, you have to remove the PTFE and/or nozzle & heatbreak.

A hot hairdryer or heatgun will come in handy next. Check if you can remove the PTFE tube (there's a black plastic ring that functions as a lock, press down on the ring while trying to pull the PTFE tube out. If the blockage is in the tube, use heatgun to try and get it out (ptfe tube is fine up to around least 250°C), PLA should soften considerably earlier.

If the blockage isn't in the tube, you'll prolly have to remove the nozzle and / or the heatbreak as well. Check e3d-online.com Wiki how to assemble, disassemble the actual hotend. http://wiki.e3d-online.com/wiki/E3D-v6_Assembly

Re: Extruder fan stopped working, ruined extruder. How to fix?

Faulty fan absolutely crucified my hot end twice. PTFE liner expanded and could not be removed. After a complete strip down I managed to remove the blockage with a fine tip soldering iron to melt the filament inside.
It's a shame I didn't notice the dodgy fan the first time as the second time was clogged even worse.
Sufficed to say I ended up replacing the fan with a Nuctua 40mm version with Patrik's custom shroud.
Haven't had a problem since.
I've heard of failure on the stock E3D fan several times now so the 40mm upgrade should be on everyone's to-do list. If not only to cancel out some of the dreadful noise on the stock 30mm version.

Re: Extruder fan stopped working, ruined extruder. How to fix?

Faulty fan absolutely crucified my hot end twice. PTFE liner expanded and could not be removed. After a complete strip down I managed to remove the blockage with a fine tip soldering iron to melt the filament inside.
It's a shame I didn't notice the dodgy fan the first time as the second time was clogged even worse.
Sufficed to say I ended up replacing the fan with a Nuctua 40mm version with Patrik's custom shroud.
Haven't had a problem since.
I've heard of failure on the stock E3D fan several times now so the 40mm upgrade should be on everyone's to-do list. If not only to cancel out some of the dreadful noise on the stock 30mm version.
I will be doing this immediately. Where can I find the custom shroud you speak of? Thanks in advance!