I have been using my MK3 for about a year with no problems, but a couple of weeks ago I started to have the following issue: the printing head loses its first layer height calibration, apparently for no reason. Sometimes it goes higher and the plastic line gets loose from the plate and sometimes it goes down, scratching the plate.
I already calibrated the first layer several times, it works for a while and then goes bad again. Today I calibrated the first layer twice, proceeded the PINDA calibration as well, flashed the new release, and nothing: my MK3 is no longer printing right. There must be a faulty part, possibly the PINDA sensor or something else. Once the first layer is done, the rest of the piece goes right, that is why I suspect that the PINDA sensor is failing.
Could you please, give me any clue on how to overcome the problem? Also, could you list the possible faulty parts so I can order them?