Unresolved Extruder not heating up.

Hello again fellow Roboers. Some of you may have seen my last post here, which was about removing and unclogging the nozzle. I've got that all done, the nozzle's reattached (and the screw I lost was replaced), but now I can't seem to get the extruder to heat up. The print bed's heating up fine, the print fan (when turned on in MC) and the heat sink fan both work, and the thermistor is working (I can see the temp in MatterControl and it increases if I take the thermistor out of its hole on the hot end and hold it in my hand). I'm also sure it's not an issue with how the thermistor is sitting: I can let it 'preheat' the extruder for a few minutes and then go and touch the hotend with my finger and it's still room temperature.

I've also ruled out a MatterControl issue, as when using Cura (and heating the extruder by telling it to print something) it still stays at room temperature. I set a multimeter of mine to 600V DC and touched the two leads to the two pins visible in the plug where the hotend's heating wire goes, and this didn't show any voltage drop. I don't know if this means that there's no power coming out, but I did the same thing to the two pins where the thermistor's wire gets plugged in and it did show a voltage drop.

So basically, the question is, where do I go from here? Any help would be greatly appreciated.

 

You can test the heater core/wire is still good by carefully connecting it to 12v and seeing if it heats up.

You can also measure the resistance. Should be like 6 ohms

 

One simple thing I found was the 120/220 volt selector if in the 220 volt position on a 120 volt circuit will work, but have a hard time getting to temperature. When switched to the correct voltage, there is more than enough power to get to and hold temperature. In the wrong position I suspect there is ~1/2 the power available and it has difficulty getting to and maintaining temperature. Check the switch carefully, it's recessed and kind-of hard to see without a flashlight.

 

Thanks all for the advice. As usual, your answers raise more questions . Mark, I gave it a quick google, would I be correct in saying that RAMPS is the arduino controlling the printer? How would I test if there was 12V coming off the ramps? Would I need to disassemble the printer? If so, how would I go about doing this?

Mike, what exactly do you mean by connecting the heater core/wire to 12V, and how would I go about measuring the resistance across it?

Ozzy, I'm pretty sure I've got the selector set right (220 for Australia) as I followed the setup video carefully and it's never had any issues heating up before.

Thanks once again to all of you, I really appreciate the support this forum gives.

 

You can measure the resistance across D10 if you have a multimeter. Just probe the two metal screw terminals.

Otherwise undo the wire and very carefully touch them to two of the 12v input power and watch to see if the extruder heats up. You only need to do this for a moment to see a response.

 

Hello Mike,
I am having a similar issue with my ROBO 3d R1. My thermistor does not heat up. I read the resistance across d1 and it is about 7ohms but I get a 0(zero) voltage read across D10 but d8 shows 12v.. How can I trace the fault from this point?

 

Assuming you have the heater enabled it should be reading 12v. Might be an issue with the ramps board. Pull it apart from the arduino and check it for any burnt solder points. That can happen if something shorts out.

 

Enkay: Unplug the connector in the heater line at the extruder area . Set your meter on 20VDC and connect it to the plug end from the board. Turn the preheat on and read the meter. If you have 12VDC the heater is bad. If you don't have 12VDC the problem is from the board. That should be your first test before tearing things apart. Frank

 

Hello all. It seems I am having the same problem, so no use posting a new thread.

I followed all the above steps, and found that when i plugged in my d10 leads (the extruder power leads) into a 12V power source, they heated up just fine (according to the thermistor reading), so my heating block is fine, its just that my board refuses to give 12V of power to D10. I re-flashed the firmware, but that doesn't seem to have fixed anything. Any ideas where to go from here?

 

yea, stepper motors still run, everything else seems to be fine. The weird thing is that its a very recent thing. it only occurred when I replaced the extruder nozzle. I'm not entirely sure if these things are linked. If its a bad RAMPS, what can/should I do to fix this?

 

I had the same issue and am very new to this. I realize it's basic advice but I found turning it off and on again went a long way. Most of the advice in this feed is like reading Greek to me, so before taking the thing apart and ordering new parts, I went that route and it's working fine now. After turning back on I reset the heat temp and having zero issues.