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Small/Medium Turntable Intermittently Unresponsive During Run — Uniboard Bug

CONFIRMED RESOLVED BOTH TURNTABLE

Summary

MRMC small and medium turntables intermittently fail to move during a run. The position numbers in Flair update as if the turntable is moving, but the motor physically does nothing. The move completes, Flair recognises the turntable did not move, and requests a goto to the correct position. Multiple operators confirmed the same behaviour across different power supplies and cables. Root cause: a uniboard disconnection bug fixed in March 2023. Fix: update Flair to the latest version (post-March 2023). Workarounds exist for older versions.

Symptoms

  • Turntable motor does not move during a run
  • Position numbers in Flair update normally as if the axis is moving — but the table physically stays still
  • The motor never moves partway — it either moves fully or not at all
  • At the end of the run, Flair recognises the position is wrong and requests a goto
  • After the goto, the system works normally — until the next random occurrence
  • Issue is intermittent and random — hard to reproduce on demand
  • Swapping cables and power supplies does not fix it
  • Also occurs sometimes during browse between waypoints

"Move programmed, everything good and happy and working well. Randomly: fwd run the move and the TT just simply does nothing. The numbers on that axis are changing, as though its moving, but in real life the TT isn't." — JMarrah, 2023-10-19

"It happens to me all the time also. Intermittently would not spin." — AlfredoMelendezCruz, 2023-10-20

Systems Affected

BOTH
  • MRMC small turntable (via Uniboard/ethernet)
  • MRMC medium turntable (via Uniboard/ethernet)
  • Confirmed on Milo rig and other systems
  • Multiple operators, multiple rigs — not isolated to one unit

Root Cause

A disconnection bug in the Uniboard firmware caused the turntable to lose communication mid-run. Because the position data continued to update in Flair, it was difficult to detect in software. The bug was identified and fixed by MRMC in March 2023.

"There was a disconnection issue with the uniboard that was fixed in March 2023. Please update Flair to the latest version and that should fix it." — Gordon (MRMC), 2023-10-25

Fix — Update Flair

Update Flair to the latest version. The uniboard fix is included in all versions released after March 2023. After updating:

  1. Check the Flair version — it should be dated after March 2023.
  2. Send a report from Flair (Help → Send Report) if issues persist after updating.

Workarounds (for older Flair versions or pre-update situations)

If updating Flair is not immediately possible, two workarounds have been confirmed by operators:

Workaround 1 — Jog the turntable axis before each run

"My solution was to jog the turntable axis before FWD Run so that it had a go-to, this seemed to 'wake it up' and it ran every time." — MikeGreenber-Mocolab, 2023-10-24

Before pressing FWD Run, jog the turntable axis slightly to ensure it has received a goto command. This appears to "wake up" the uniboard communication.

Workaround 2 — Connect the turntable before booting Flair

"Niko suggested booting up the Flair system with the turntable already connected, instead of connecting it after Flair was already running. Since switching our process to connect the turntable before turning the system on I've not encountered this issue any more." — MikeGreenber-Mocolab, 2023-10-24

Boot Flair with the turntable already connected and powered, rather than hot-connecting after Flair is running.

Source: talk.mrmoco.com — Small turntable inconsistency — Posts by JMarrah, AlfredoMelendezCruz, MikeGreenber-Mocolab, SQF_Felix, Gordon (MRMC), 2023-10-19 to 2023-10-25

Revision History

Date Change Editor
2026-05-29 Initial extraction from forum topic 1419 Tom D / Claude Code