Mk 2.5 extruder skipping not printing  

Mk 2.5 extruder skipping not printing

I converted my 2S to a 2.5 and no problem until a few days ago. I noted that although the printer kept going, the filament stopped extruding and the motor was doing clicks (indicator showed it was not moving - slight forward with immediate click back). If I paused print and unloaded filament then reload filament it starts working OK again. On my last attempt it stopped at 3 different layers. Each time I unloaded, preheat, reload and it printed OK again till it stopped. Finally it stopped cold and said "preheat error". Note that I had tried to raise the temp as it stayed at about 200 degrees (done due to a similar temperature problem - see below) even when I set it to 215 degrees and even lowered my hot end fan speed to 175. If I leave it alone it has on occasion finally started extruding again. I have used the same filament(s) multiple times with no problem. I changed out the nozzle, adjusted the screws to the extruder idler (multiple times), tried printing at 125%, changed nozzle temp for PLA down to 200 degrees, all to no avail. I also checked both Bondiech pullies alignment. When I unload the filament the gear marks are OK (don't show grinding), the end show a small (.5mm) bulge for about 3mm length but it looks like it just sat there under heat ad bulged (still has gear marks). In any event, it unloads OK. I will say I am doing 9 hour prints but this starts at various times as soon as the second layer and as late as 4th layer, or not at all. I was trying to print some gifts for my Christmas cards but am at all stop until I can resolve this problem.

I would add that since I did the firmware and software updates this summer, my printer does the first PLA layer at 215/215 degrees but then the temp goes 200/210 degrees for different amount of layers. The tech support said reduce the fan speed and that usually works but a person should not have to do that. Actually printing PLA at 200 degrees is not a problem but not the right answer. I don't think the two problems are related.