During long-term operation of 3D printers, belts may stretch, causing looseness that affects print quality and machine stability; therefore, regular belt tensioning is necessary.
Manual tensioning is mainly to avoid situations where, after long-term use, the belt has loosened beyond the automatic tensioning adjustment range. In such cases, manual tensioning can be used. Turn clockwise to tighten the belt, counterclockwise to loosen it.
Use an L-wrench to tighten the two screws below 2-3 turns clockwise.
Then re-execute Settings - Device Self-Check - Input Shaping.