I have an Ender 3 Pro with the BTT SKR E3 V2.0 mini with Marlin firmware 22.214.171.124.x. I am trying to print PETG, which requires decently high temperatures.
I initially replaced the stock board after a thermal runaway event that seemed to have damaged it. After installing the new board and getting all the settings dialed in (typically 260 °C hotend and 90 °C bed), it worked great for about 2 weeks until I got the thermal runaway event error again.
Here is what I have tried so far
- replaced the thermistor with this
- replaced the heating cartridge with this
- replaced the hotend with this an all-metal one
- measured voltage coming from the power supply and coming out of the board going to heater cartridge (both ~24 V)
I PID tuned the printer using
M303 E0 S260 C10 and stored new PID values in EEPROM + firmware. A note, running this multiple times seemed to constantly increase the P and D values. I stuck with the initial values given (
kP 13.97 kI 0.84 kD 57.96). I still continued to get thermal runaway events.
I then tested the heater cartridge and thermistor with my multimeter. The heater was 13.5 ohms which seems about right. I was unable to measure the thermistor value. Searching online shows I likely need a better multimeter to do so. It's possible it is bad, but I find that hard to believe considering this issue was happening prior to my replacing it.
Example log of the failure happening. All I did was heat the printer up, leave it on for a bit, set it to cool down briefly, then tell it to heat up again. The printer was heated for ~5-8 minutes before this log starts.
Could this be the board again, or is there something else I'm missing?