Hotend Break
As I was FINISHING cable management of my first i3 Mk3s I noticed this lead to the hotend had broken. No idea at what point or how but I imagine from moving unit around during cableing. I started to reverse the X axis carriage install but of course that means the belt also. Is it possible to replace this cylindrical piece that the leads are attached to? Or the whole block that the tip is attached to. Trying to avoid pulling the hotend. I don't know the names of everything yet so please forgive my poor descriptions, I am in technical depression.
RE: Hotend Break
That’s your heater cartridge. The small button headed hex screw you can see on the bottom can be loosened and then the heater cartridge should just slide out. It acts as a clamp to hold it in place. Replacements can be found either on the Prusa shop or you can get them from e3d direct, 24v 40w is the type. You can also get them from other places like amazon etc but the originals are made by e3d and it’s best to get a like for like replacement.
RE: Hotend Break
This item is a 24 volt Heater Cartridge, It is held in place by the single, Black, Round head screw in the heatsink.
If you raise the extruder by the LCD Menu if possible, or whilst the printer is turned off, you raise the extruder by simultaneously turning both Z axis Lead Screws at the same time, you can reach this screw with an allen wrench.
slacken the screw, and you should be able to push the heater out of the aluminium heat block then you can undo the cable ties and remove the heater wires from the wiring loom...
the Mk3 heater is a 24volt 40watt heater, available from the Prusa shop, oe E3D online, or one of their resellers. (And other vendors!)
NOTE! IF YOU GET THE WRONG VOLTAGE IT WON'T END WELL!!!!
A 12 VOLT HEATER WILL TRY AND DRAW 4 TIMES AS MUCH POWER AS THE PRINTER EXPECTS TO GIVE!
Regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend Break
@joantabb
Thank you Joann, very good explanation. I didn't even have to read it twice, although I will. I am still in the build phase of my new unit, sooo close to complete when this happened. I will order the new part today. A 12v would draw 4x the power, whats the formula for that, VxW=A? I have a lot to learn which is exciting.
RC
RE: Hotend Break
@neophyl
Thank you very much, quite clutzy of me but when I first saw those wires, I smelled trouble.I will check out E3D online.
RC
RE: Hotend Break
@rcurschman
Hi RC,
Please have a look at the picture below, 
Top left are the figures for 24 volts with a 40 watt heater, Top Right are the figures for 12 volts with a 40 watt heater,
Bottom left are the figures for a 12 volt 40 watt heater, driven at 24 volts... = BAD NEWS... 160 watts (FIZZ BANG WALLOP)!
Bottom right are the figures for a 24 volt heater driven at 12 volts... = bad news ... only 10 watts. would only get warm
I hope that makes sense! regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend Break
@joantabb
Joan, Thanks again, it does. On another subject, I just ordered the 24v 40 watt heater cartridge and some PTEG prusament. I only have the smooth sheet to print on. Should I order the textured sheet for PTEG? Trying to bundle these into one shipment. I have not seen a list anywhere of suggestions of additional things beginners ought to buy with their kit, I think it would be helpful.
RC
RE: Hotend Break
Hi RC,
I like the textured build plate. and use it with both PETG and PLA, I have several from different batches, and no problems... others have different experiences...
don't forget to set up your alternate bed profiles, to make it easy to change between beds later!
I would order an extra heater and a spare thermistor. because it is ALMOST guaranteed that you will have a Blob of Doom... sometime soon. it's like a right of passage! if you have spares, you can get on with repairs straight away...! Yeah I am a kid with new toys... most of the time!
this is someone else's Blob, for example... I don't have a personal example available...
you need to be really careful trying to remove these, as it is incredibly easy to break your thermistor wires and heater wires...
the fan shroud is another common victim... they are normally printed in ABS. if you print one in PETG or PLA as an emergency spare it will be your 'get out of jail free card'...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend Break
Adding a few e3d silicon heat socks goes a long way to making things easier to clean if you do have a print come loose. They also help insulate the hotend reducing heat drop when the part fan kicks in. Basically for the price they are a must have. Not sure if Prusa stock them though but you can order elsewhere.
RE: Hotend Break
@joantabb
Joan, The spare Thermistor cable you mentioned is for the hotend correct? Not the Heatbed?
RC