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Electronic Theatre Controls Inc

Eos Classic Motor Faders Sluggish


The information in this post is provided to assist in troubleshooting. Perform work at your own risk. ENSURE ANY POWER FROM DEVICES HAS BEEN DISCONNECTED BEFORE SERVICING ANY EQUIPMENT. If you do not feel comfortable performing the work, please contact us or your local service center. Be aware that ETC and its Affiliates are not responsible for any damage or injury caused by service of our products by anyone other than us or our authorized service providers, and such damage is excluded from the product’s warranty.


Eos Classic motor faders can become sluggish or lag after being left idle for a while – this amount of time can vary based on site conditions and could be between a few days and a few months. When this occurs, the motor faders may not travel the full length of the fader or they may undershoot their target.

This behavior has only been observed on the Eos Classic faders as they age. If you are experiencing sluggishness on other ETC products that use motorized faders, please contact ETC Technical Services.


Exercise the motor faders. You can do this manually or automatically.

Manually, move the faders up and down for several seconds through their full range of travel.

There are two ways to do this automatically.

  1. Exit to the shell and open the Face Panel Test. Select the Motor Fader test. Check the boxes to move the motor faders from 100% to 0% repeatedly.
  2. In a showfile, map a submaster at full to all ten faders. Change fader pages to an empty page (or a page with a different submaster at 0). Repeatedly switch between these two pages (or write a looping macro to assist).

After several seconds to a few minutes of exercise, the motor faders should return to their full rate of travel.

Please Note

The tolerance range of the motor fader movements are +/- 7 steps (out of 255) from the target value. This means that if a value of 127 (50%) was sent to the fader, it should stop between positions 120 and 134. Repeated fader exercise can help get the fader back within this tolerance.

If motor faders still are too sluggish or do not move at all, contact ETC Technical Services to discuss a factory repair.

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