Heating self test fails, replaced everything. Still stuck. Please help
I have a MK4S with MMU3 (I'm running the latest firmware (MK4: 6.3.1, MMU3: 3.0.3).). Awhile back I started having trouble and my prints would fail for no apparent reason. I did the calibrations and discovered that the heating test failed, specifically, the "Heater testing" failed for the nozzle. I checked everything I could; I measured the resistance of the thermistor and the heater of the hot end. I tested the thermistor of the NTC. Everything was within spec (98–107 kΩ).
I got in touch with Prusa support and they even sent me a new LoveBoard as that's what seemed to be the problem. I replaced it and the test is still failing. I've replaced the entire hot end (block, nozzle, thermistor, heater) and get the same results. I've tried playing with the configuration of the test (silicon sock, hardened nozzle, etc.) and nothing seems to make a difference.
I'm kind of at a loss for what to do next. I can print with a single color, but I don't know how much longer that is going to last. I'd like to get my MMU back, but I have to get the heating test to work first.
Can anyone help me?