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Milo Roll Movement Causes Wireless Genlock Dropout

Summary

On a Milo crane, significant roll movements can cause the camera to briefly lose wireless genlock sync. The root cause is electrical: the Milo roll axis worm gear nearing end-of-life draws more motor current, generating EMF. Unterminated lens motor cables on the Milo umbilical act as antennas and pick up this EMF, which trips a limit in the multiplexer IC — dropping the sync signal.

The fix is to terminate all unused lens motor ports with either a connected motor or a custom female terminator with the limit pin grounded.

Symptoms

  • Camera loses genlock for a second or two during any significant roll movement on the Milo.
  • Issue happens consistently with roll, not with pan, tilt, or track movement.
  • All cables and physical connections appear solid.
  • Camera body and genlock box otherwise work normally on other rigs.
  • Wireless genlock (e.g. ACN Lockit Box) is more sensitive to this than wired genlock.

Root Cause

The Milo roll axis uses a worm gear drive. As the worm gear approaches end-of-life, the motor must pull significantly more power to move. This increased current generates EMF. Unterminated 5-pin lens motor ports on the Milo umbilical have floating limit/signal pins which act as antennas — when the EMF pulse hits the right frequency, it trips a limit threshold in the multiplexer IC driving those ports. The spike on the lens bus then couples into the sync distribution, causing the brief dropout.

"Roll ring worm gear is nearing EOL, motor pulls more power, generates more EMF, unterminated lens motor cables act as antennae and trip the limit in the multiplexer IC. Solution was to terminate, either with a motor (or make a female terminator and ground the limit pin." — Colin Michael Quinn, 2026-06-04

"Could just be noisy EMF coming off of the roll motor if it happens to be heavily in that same frequency." — Josh M, 2026-06-04

Fix

[CONFIRMED] Terminate all unused lens motor ports

Plug a motor into every unused lens motor port on the Milo umbilical, or make a female terminator by wiring the limit pin to ground. Either approach prevents the floating pins from acting as antennas.

Confidence: 0.85

Steps:

  1. Identify all lens motor ports (focus, zoom, iris, aux) on the Milo umbilical.
  2. Check which ports have motors connected.
  3. For every unused port:
  4. Connect any spare MRMC motor, or
  5. Make a female 5-pin terminator: short the limit pin to ground.
  6. Test roll movement — genlock should now remain locked.

Secondary: Check worm gear condition

If the termination fix resolves the symptom but the worm gear is known to be aging, schedule a worm gear service with MRMC. A healthy worm gear draws less current and generates less EMF.

Confidence: 0.7

WhatsApp Excerpts

Timestamp User Evidence
2026-06-04 00:40 TIMOTHY SMITH "Using an ambient recording acn lockit box for wireless genlock on Milo and VP stage. Anytime there is significant roll movements the camera loses genlock for a second. On Red Komodo. All cables and mounting are solid. Only happens with roll movement."
2026-06-04 03:55 Josh M "Could just be noisy EMF coming off of the roll motor if it happens to be heavily in that same frequency. I'm surprised the box can't maintain sync for that short period of time though without a solid connection."
2026-06-04 04:00 Colin Michael Quinn "This was a discovery Peter and I made a few weeks ago. Roll ring worm gear is nearing EOL, motor pulls more power, generates more EMF, unterminated lens motor cables act as antennae and trip the limit in the multiplexer IC. Solution was to terminate, either with a motor (or make a female terminator and ground the limit pin."