SQ6 Master fader slow and uncalibrated

The master fader on my SQ-6 is slow to report changes and slams against the end stops when changed remotely.

So far I have tackled all the basics:

  • Gave it a good cleaning with compressed air
  • Power cycled, soft reset, and hard reset
  • Downgraded to 1.44 and upgraded back to 1.5
  • Calibrated the faders at every step

Any additional suggestions before I take it in for service? Any recommended places for service in the midwest?