RE:
I'm focusing on adjusting belt tensioning. Quick gantry alignment is a particular focus.
4. Check the alignment with the belts still loose, and carefully push the gantry forward. Since the loose belts will not pull it all the way, you may need to guide it by hand. Verify that there is no gap on either side at the front position.
- When I've loosened the belt tensioners I'm unable to bring the gantry flush with the front stops as suggested. So far I tighten both sides until I can't detect slack by tapping the gantry against the stops on left and right front sides.
- I've updated the bios to support the harmonic based tuning of the belts but don't have the knack of dialing it in within the required frequencies.
- At the moment, I have the gantry within the frequency ranges, but it's still failing with the precise refinement error.
It seems you are following the most recent version of the belt alignment instructions, great! I assume you have also installed firmware 6.4.0 RC2 to have access to the stroboscopic belt tuning then?
But you have only quoted step 4 of the "Quick Gantry Alignment", which is to confirm that the gantry is aligned. Steps 1 to 3 tell you how to get it into alignment -- not by asymmetrically tensioning the belts, but by slightly bending the gantry (actually its mounting brackets) while the belts are fully relaxed.
Only afterwards you start tensioning the belts again. As mentioned by @hyiger (and the instructions, step 5 of the gantry alignment), be sure to tension them symmetrically. That should get you to a place where the belt tensions are in the ballpark, so the stroboscopic belt tuning wizard can take over, while the gantry is still straight.