Extruder Heating and Feedback Problem

[jeffhuber]

Hey all,

So I'm having a strange problem with a couple of rostock max v2s I just set up. I built the two printers in parallel, so they are set up similarly.

In the first printer, once it was completed, it seemed to be working fine. Both the extruder and the bed were working and the temperature readings were fine. Then in trying to home the printer,the axis directions were backwards and the extruder crashed into the bed before I could catch it. I went back and reversed the axis direction, rebooted the printer, and the calibration worked fine, but there was an error with the sensed extruder temp.

Firstly, the temp reading from the thermistor showed a temperature that was impossible: ~3C. The bed was at room temperature, and could still be heated just fine. I checked the wiring and nothing appears to be wrong. No shorts. It just shows an abnormally low temperature. Moreover, when I try to heat the extruder, it starts to warm up, and the fan turns on, but the temp reading on the display and in RepHost does not change from readings < 10C. And it seems like the extruder is heating up towards the temperature I set it for (250C); it is getting hot enough at least to melt PET.

In troubleshooting for the problem, I switched the board out with one from a printer that was working fine (though the extruder was heating up way too slowly) to see if it was a firmware problem or related to mechanical stress of the extruder crashing into the bed. Now, both printers are reading abnormally low temperatures for the extruder, which makes me think it's a software problem, but I don't know why it would affect both printers if one of the boards was working fine.

I'm using the E3D-v6, and I changed the thermistor definition to correspond to this hot end (i.e. #define EXT0_TEMPSENSOR_TYPE 8). I thought this might be the problem, but it didn't change anything once I re-uploaded it.

Any advice?

[Eaglezsoar]

Hey all,

So I'm having a strange problem with a couple of rostock max v2s I just set up. I built the two printers in parallel, so they are set up similarly.

In the first printer, once it was completed, it seemed to be working fine. Both the extruder and the bed were working and the temperature readings were fine. Then in trying to home the printer,the axis directions were backwards and the extruder crashed into the bed before I could catch it. I went back and reversed the axis direction, rebooted the printer, and the calibration worked fine, but there was an error with the sensed extruder temp.

Firstly, the temp reading from the thermistor showed a temperature that was impossible: ~3C. The bed was at room temperature, and could still be heated just fine. I checked the wiring and nothing appears to be wrong. No shorts. It just shows an abnormally low temperature. Moreover, when I try to heat the extruder, it starts to warm up, and the fan turns on, but the temp reading on the display and in RepHost does not change from readings < 10C. And it seems like the extruder is heating up towards the temperature I set it for (250C); it is getting hot enough at least to melt PET.

In troubleshooting for the problem, I switched the board out with one from a printer that was working fine (though the extruder was heating up way too slowly) to see if it was a firmware problem or related to mechanical stress of the extruder crashing into the bed. Now, both printers are reading abnormally low temperatures for the extruder, which makes me think it's a software problem, but I don't know why it would affect both printers if one of the boards was working fine.

I'm using the E3D-v6, and I changed the thermistor definition to correspond to this hot end (i.e. #define EXT0_TEMPSENSOR_TYPE 8). I thought this might be the problem, but it didn't change anything once I re-uploaded it.

Any advice?

I am responding to this just to bring it to the forefront again. Can anyone suggest a solution?

[JFettig]

Are you sure your thermistor wires are not shorting out on the heater block? One of my sheaths got cut too short so it shorted out - I forget what it was reading but IIRC it was really high(1000 degrees), later on after clamping and unclamping the thermistor a couple times I wore through the sheath, same issue.

Do you have them plugged into the correct input?

[Eaglezsoar]

jeffhuber, has this problem been resolved?