During a filament change, M600, the heater cools down by about 10-15 degrees, which is to be expected, and when the filament is loaded the heater tries to warm up but cannot achieve it's desired target and the printer halts in the middle of a print...however when I reset the printer after the halt it has no problem reaching the desired temp. This would lead me to believe that there is a control issue either in hardware or firmware because the heater is clearly able to heat to the target temp but for some reason if that temp drops below a certain temp while printing it is unable to recover. You might say that's because there is filament being pushed through the nozzle or the cooling fan is too aggressive, but this happens when the printer is warming up after a filament change when there is no part fan running or filament running through the nozzle.
There is a more detailed explanation with heater graphs here: [
github.com]
