Extruder problem


I experienced some problems with my Rostock V2 when I blew a fuse due to shorting out the thermistor. I replaced it and I had problems with the hotend getting plugged, then the extruder stopped working. I ordered a new extruder motor and it still does not work.
-The 3 stepper motors on the tower work fine as does the fan control. I note that there is a flashing set?? of yellow LEDs marked T and R not sure what that means.

Any help?? Printer ran really well before this now I am getting frustrated.


Hi Dennis,

I’m not an expert on delta printers, but I hope I can help you get a good response to your questions. Specifically, what DOES the printer do and not do.
[]Blowing a fuse by shorting a thermistor is unlikely unless it is on its own low current circuit. A shorted thermistor would read high (or low) and cause firmware to turn the printer off due to thermal shutdown.
]The hotend getting plugged can be caused by several conditions. Material in the nozzle, heat too low, PTFE tubing misaligned or melted. If your extruder also stopped working this could make it look like the extruder is clogged.

So, does the stepper spin? Does the extruder get hot? Does the thermistor provide a signal? Does the circuit with the fuse work? Knowing which parts operate and which don’t will help identify the source of the trouble.



Hi Stefan.

The stepper does not spin at all, even when I ask it to spin. The hotend gets hot and comes up to temperature. This printer was seccond hand and the previous owner used aluminum tape to cover the wire joints, therefore the short, which blew the fuse. I have remove all aluminum tape and replaced it with Kapton tape.
The printer seems to work in all other respects, the X,Y and Z motors work, the hotend and bed heats and the LCD lights up and I can go through the menus.

Thermistor works now, as I have replaced it.

Very frustrating!



Hi Dennis,

Thanks for the update. So, the extruder motor will be running on a different circuit than the hotend (and thermistor). If you just replaced the motor and are getting no movement, I think one of two situations are likely:
[]Something has shorted on the control board.
]The motor’s wiring is not correct.

Don’t trust that the same colors (or even positions) should match on the new and old motors unless you have the EXACT same model. If you temporarily swap your x or y motor with the extruder plug, you should be able to find out which problem you have. If it’s the motor, we can figure it out by trial and error. If it’s the board, we may need to seek more advice.



Hi Stefan

I am afraid it maybe the board since I bought the motor from Seemecnc and it is an exact same model. I swapped out a stepper motor from the X axis and still does not work

Not sure where on the board I should look for a short.



I have to go out of town for the next 5 days, I’ll hopefully have some answers/ suggestions from the forum by then, and I can get back to printing.



One additional thought. Swap the motor driver if you can.



As far as I know any drivers are on the Arduino board. Don’t think there is a way to swap the motor driver. BUT I am in no way knowledgeable about these things. Just an old fart trying to get into 3D printing.


Hi Dennis,

Looked it up: it uses a RAMBo board which is a combined Arduino and RAMPS in one. It is replaceable and well documented depending on your skill and inclination. Probably able to use a basic Arduino/RAMPS which is a bit cheaper (though a few here may yell at me for suggesting it :lol: ). The good news is that you could use an updated version of Marlin (firmware).



Totally frustrated, can’t see where on the board anything was burned out. All fuses are fine, all stepper motors (except the extruder motor) are working fine. The printer runs as if everything is all right.
I wonder since the board is set up for 2 extruders if I can run one extruder on the second plug?



Hi Dennis,

You’ll have to switch the extruder in firmware, but you have an excellent idea.



Got nothing to lose. I’ll read up on it and give it a try.