(This is a graph of 3 or 4 startup attempts)
I have been having this issue with heater cycling when trying to warm up for a print.
Symptoms: When warming up, the heater gets close to the temperature desired, then spikes, followed by an excessive drop, pause than repeat. The cycles are regular and have a clear pattern. The cycles are roughly equidistant from the desired temperature.
History: This is a 2 month old printer. This issue started to happen after about a month of use, I think; though it could have been happening earlier and, due to my lack of experience, I may not have noticed. The problem was solved by turning the power on and off. Now, this no longer seems to be true; though I have not tried again since last night.
Attempted Solutions: Re-routed a dandling thermister wire, re-calibrated everything, reset to factory and them flashed and then re-calibrated everything.
I've been in contact with customer support; and I think they are researching this (my support guy is extremely helpful). Has anyone else had an issue like this? I feel sad seeing the printer sitting there idle <pout>
The consensus on the Discord channel is that it is a problem with the system reading the temperature and not the heater actually cycling. The theory is that the heater cannot change temperature as dramatically as the graph shows. So the problem is theoretically narrowed down to a bad/failing thermister or Eisny.
I changed out the thermister, then did a brief test and did not have the cycling issue; however, seeing as it was sometimes intermittent, it's not conclusive. I've torn down the printer to incorporate the new thermister and will report back after I have had a few good prints to test it. I really hate having this massive wire bundle to manage and cannot wait for the new version (praying it had some kind of quick disconnect block...)