Upgrade from MK2 to MK2.5 - Finally some good prints!
My "assemble yourself" MK2 was a workhorse. A few failed prints but the issues were likely caused by me and not the printer.
I upgraded to the MK2.5 latter part of 2018. Small parts printed o.k. but larger and longer prints always resulted in one or more dramatic layer shifts.
I read on this forum that others were having this same issue and the one that caught my attention was the one that seemed to pinpoint the problem to the Rambo board getting too hot. This made sense to me.
I modeled a new Rambo enclosure to incorporate a 120V 80x80x25mm case fan and swapped out the enclosures. I eliminated the slots on the front and back of the enclosure and only added openings where the air will enter the case fan where it attaches to the back. The entering air comes in from the open bottom. This case fan is most certainly overkill but it was all I could find that I could plug right into a 120V receptacle.
So far so good with perfect prints, once again!
Could it be that some of us have Rambo boards that are more susceptible to heat than others? Clearly the Prusa team realized that additional venting was required based on the replacement Rambo enclosure that was necessary as part of the upgrade.
I will keep my fingers crossed that my layer shifting days are now over with. No more rats nest of filament all over the place and the elimination of tons of filament on the nozzle and hot end upon inspection hours later that the print shifted/failed.