This article is about the OT-One.

It's no-longer sold or actively supported by Opentrons, but we've kept this article here to help existing users. Please see our OT-2 Support articles for the most up to date information!

If the belt tension on your OT-One is too low, the belt will slip causing noise and poor functioning of the belt-driven axis. 

Materials required:
M5 Allen Key
8mm / 10mm wrench


  1. Manually grip and squeeze the belt around the belt pulley. The belt should have a firm tension with little to no slack.

  2. Completely loosen the screws on the horizontal component of the 90 degree corner bracket. For the vertical component loosen it enough to be able to move freely. If you have a Hood robot (featured below) you will be able to slide the bracket off but on the Pro model, you will not be able to completely remove it. Be careful not to completely unscrew the inner insert off of the screw.

  3. Slide the bracket upwards and remove the 3D printed belt hardware.

  4. Fold the belt an additional notch or two to apply additional tension

  5.  Reassemble and tighten the bracket with the belt hardware

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