Extruder Won't Heat Up  

Re: Extruder Won't Heat Up

Patrick

What does the LCD display show for the extruder?

If it shows RoomTemp/RoomTemp then the required temperature has not been registered properly.

If it shows RoomTemp/RequiredTemp then you don't have the extruder heater connected properly.

If it shows 0/AnyValue when you don't have the extruder thermistor connected properly.

Peter

Re: Extruder Won't Heat Up

Peter,

Here is what I'm seeing on my display

I've also check the voltage at the wires coming out of the extruder and measure 12 V, but when I measure resistance I detect an open circuit.

Re: Extruder Won't Heat Up

OK, so there is a problem with the extruder heater or the cable.

As the cable goes directly all the way to the heater, if there is an open circuit, the only thing I can suggest is:

Unscrew the RAMBo extruder connector screws
Check the resistance across the ferrules
If you measure 5 to 7 Ohms then the ferrules were not making a good connection in the connectors. Rectify that.
If it is still open circuit, cut of the ferrules, strip the wires back 5mm and test again.
If you measure 5 to 7 Ohms, then the wire were not making good contact inside the ferrules Try with the stripped ends screwed into the connectors.
If it is still open circuit then you need a new heater; contact Prusa Research, give them a link to this thread.

Peter

Re: Extruder Won't Heat Up

Peter,

I removed the ferrules from the RAMBo connector and still detect an open circuit. I haven't tried stripping the wire back yet, but I did notice while the extruder was unplugged I didn't have any errors listed on the LCD. I would assume I would see a min temp warning or something.

Re: Extruder Won't Heat Up

No, there won't be any errors when you unplug the extruder heater. That is effectively a "write-only" device and the thermistor reports the temps.

Peter

Re: Extruder Won't Heat Up

Ah that makes sense. Well I forgot I plugged the extruded back in and ended up blowing the fuse while measuring resistance at the extruder. I'll have to get another 5a fuse.

It still appears that there is an open circuit across the extruded. I'm a bit nervous to strip the insulation away to test it. I don't want it to appear that I damaged it.

Re: Extruder Won't Heat Up

Patrick

Oops...

I think this thread will show that there is a strong possibility that the heater cartridge has a bit of a problem, so you should be OK stripping back the cable to test the resistance.

Get in touch with support and give them a link to this thread.

Or you could just buy a 12V 30W heater cartridge from eBay/Amazon/etc; they are very cheap.

Peter

Re: Extruder Won't Heat Up

Replaced the fuse today, and now the extruder is heating up. I'm a bit confused on why this fixed it, because I'm pretty sure it wasn't blown when I started troubleshooting (I heard it pop while trying to figure out what was wrong with the extruder). I guess I'll reassemble everything and see if it still works.

Thanks for the help.

Re: Extruder Won't Heat Up

Patrick

I think that is good news. Well done.

Peter