RE: Tension pulley broken
Out of those two, ASA and PC Blend, I would say that PC Blend is probably stronger and more heat resistant, but I have no experience with it personally. My CORE One has been using ABS tension pulley parts for several weeks, and is working perfectly. I used 4 perimeters and 100% infill. ABS can evidently stand the tension force, and after an initial settling period (which I think is normal even with the original PC-CF parts) it is maintaining the correct belt tension perfectly. I expect ASA would be at least as good as ABS for this part, so I think you can use either of your filaments in this case.
If you do decide to just fit the supplied PC-CF parts, make sure you lubricate the tension screw threads, keeping the screw heads clean and dry. This will protect against the galling issue.
RE: Tension pulley broken
And check your belts where they feed through the pulls at the back, I discoverd my issue was I had one of the belt driving gears reversed and that's why I as having all the homing issues and why I had all the issues with tensioning that caused me to strip out the nut in the tensioner in the first place.
RE: Tension pulley broken
One of the motor pulleys is supposed to be reversed relative to each-other. That is, one has the pulley close to the motor, one away from the motor. Though it seems a lot of people just skim the detailed instructions here and mount both the same, missing the important detail.
And check your belts where they feed through the pulls at the back, I discoverd my issue was I had one of the belt driving gears reversed and that's why I as having all the homing issues and why I had all the issues with tensioning that caused me to strip out the nut in the tensioner in the first place.
RE: Tension pulley broken
Normally I do read the instructions and follow them exactly. My guess is that since I did the process over a few days, I likely got interrupted or was tired. I'll own up to my mistake though lol
RE: Tension pulley broken
Super easy to do, not judging at all - just making sure theyre now not the same orientation and anyone skimming rhe thread doesn't end up confused.
I had to disassemble and redo a couple things myself - just caught them during assembly.
RE: Tension pulley broken
yeah I learned a lot in the first upgrade. I have no doubt the second(still sitting in the box) will go better. I'm not in a rush to upgrade my 2nd mk4s. There's something nice about being able to just grab the printer and take it out of the enclosure to look at things, lube rods, etc. I'm going to miss that when I upgrade the 2nd one.
Super easy to do, not judging at all - just making sure theyre now not the same orientation and anyone skimming rhe thread doesn't end up confused.
I had to disassemble and redo a couple things myself - just caught them during assembly.
RE: Tension pulley broken
The other very common mistake people make is to improperly tighten the pulley set screws. Set screws must be tightened FLAT FIRST, then tighten the set screw on the round. The set screw on the round locks the ss on the flat in place.
If you tighten the ss on the round first, the set screw on the flat can wobble loose because it will not be perpendicular to the shaft flat.