Welcome! Log In Create A New Profile


RE existing Marlin bug #14470 on SKR 1.3

Posted by dant220 
RE existing Marlin bug #14470 on SKR 1.3
February 04, 2021 02:06PM
Hi All;

I have been trying to fine tune settings on an SKR 1.3 running on a Wanhao I3. Recent version of Marlin ( All was going well enough until I was printing a couple of layer print to test bed adhesion and Octoprint disconnected with Bed Temp error. From then on I could never connect again. Unless I turned the machine on and connected very quickly where I would get a message from the printer saying it loaded the EEPROM and then Octoprint would lose connection. I surmised that Marlin was crashing. Several days of hair pulling ensued until I came across this on Marlin Git Hub:


Reading this it looks like the EEPROM can get garbled especially around bed temperature. So I imagined if I set the bed and nozzle to thermistor 998 (or 999) it might help and it did. I can connect. I reset the factory defaults in hopes to clear this issue. But it does not. So my question is how do I get around this issue so that my printer is not a fire trap?

As a side note my thermistors worked as type '11' which is 25 Degrees C @ 100k. My ambient is around 22 and it is just above this. And if I warn the hotplate with my hand the resistance decreases. This to me is enough to say the thermistor is working.
Re: RE existing Marlin bug #14470 on SKR 1.3
February 07, 2021 12:56AM
I figured it out. Posting it here to help others.

The issue was the pin for the Extruder was bad. I figured this out by creating 2 different compiles By editing values for "TEMP_SENSOR_0" and "TEMP_SENSOR_BEDTEMP_SENSOR_BED"
  1. where the extruder temp was set to be a dummy (998) and the bed was real (11)
  2. Where the Bed was a dummy (998) and the extruder (11) was real

Option #1 did crash while option #2 did not. This told me something was wrong with the extruder either heater or sensor or pin.

To test the heater while using compile 2 I turned on the heater. WARNING THIS IS DANGEROUS TO KEEP THIS ON try not to start a fire I kept my finger on the heater and it warmed up. I QUICKLY turned off the heater (fire averted). I know the heater is good.

The sensor I tested with an ohm meter. It checked out.

The last thing it could be was the port.

I found the pins in "Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h"

I swapped the pins in "TEMP_0_PIN" and "TEMP_1_PIN" (the thermistors on Extruder0 and Extruder1), I moved the physical connector, Reset the thermistors from the bed and the extruders to the correct values in configuration.h (in my case that is 11 for both).

Fired it up and it works!!
Sorry, only registered users may post in this forum.

Click here to login