So, I haven’t been printing much (just a couple of temperature towers) this weekend, though I did get a couple of other projects done. I went to start on a 6.5 hour print last night that I had to abort just a few minutes in, because the Y stepper connection to the RAMPS vibrated loose (second time now). This morning I reconnected it (also bent the pins slightly to give a bit more grip) and started again. This time I aborted it in a few minutes because the leveling screws loosened (I probably ought to be looking at alternative infill patterns). I took a trip to my favorite home products store and got a tube of blue Loctite, brought it back and reinstalled the leveling screws and reconfigured to have my Z home with a level bed. I had company coming for dinner so I thought I’d fire it up to show it off. It moved around just fine but wasn’t extruding. I manually pushed some filament through and it felt just fine so I tried just running the extruder for 10mm or so. No filament. I double checked the connection on the RAMPS an it was fine. I pulled the extruder apart far enough to see the stepper shaft and it only rocked back and forth when trying to extrude. I pulled it farther apart and tried to move the stepper with nothing attached. Same thing, it only rocks back and forth. So … I swapped the stepper out for a new one. Same symptom! (At this point I was mumbling to the effect of darn, shoot, heck, etc.)
So my next step is to tear the wiring harness down and test the cabling. Has anyone got other suggestions?
I’m also going to look at redoing the leveling screws to tighten up the bed to minimize the rattle, maybe bushings instead of linear bearings under the bed, though mostly it should clear up if I slightly resize the holes and switch from 3mm to 6-32 screws. I find the thumbwheels under the bed are hard enough to reach that I adjust by holding them and turning the screws at top. Since the 6-32s are an interference fit in the aluminum heater bed I switched to 3mm early on, but they are obviously too loose to keep everything in place.