Ender 3 Pro, everything is stock except that I swapped the magnetic sheet for a glass bed.
As the tin says, I'll get this error around a half hour into a print:
THERMAL RUNAWAY: E1
PRINTER HALTED
Please Reset
I recorded it in the act, and here's some info I've collected:
The Extruder temp isn't consistent. It's set to 200 °C (Cura default), but will often wander around in the 197 °C-202 °C range.
There are random severe spikes where it will instantly go from 200 °C to 190 °C, then climb up to 205 °C.
About 5 minutes before error, it instantly dropped from 200 °C to 170 °C, then 180 °C, then 190 °C, then chilbed back up to 200 °C.
The error popped in when the extruder was at 190 °C.
See, it seems to jump around in an odd pattern, not just smoothly transitioning to a lower temperature. This leads me to suspect it's a sensor issue.
However, around the time these jumps were occurring, the plastic wouldn't adhere to the plate correctly. Some parts wouldn't stick:
Compare the bottom (printed first) to the top (printed last). A lot of edges are popping up (although the bottom isn't perfect either).
This wasn't an issue until I moved my printer to the basement (from my bedroom) for a 30-hour print. I had it running for ~14 hours straight before my first encounter with this error. The temperate difference between my room and the basement is minimal.
I also leveled the bed before re-trying, which didn't solve the issue.
I am new to this, I got the printer 3 weeks ago. Extensive googling has resulted in many different solutions, but none specific to my printer's temperature situation. I post this hoping to find clarification for myself and provide a concise description of the problem so others down the line can find the solution easier.