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Electronic Theatre Controls Inc

Sensor3 Has Blank Screen and Red Panic Light


Sensor3 processor (CEM3) has a backlit but blank screen and the panic light is lit.  No control of the circuits.


When the CEM3 is powering on, for a brief instance the screen will be lit and blank and the Panic, DMX A, and DMX B will be illuminated.  Shortly after this, the screen will populate with "ETC CEM3" and continue the boot up process.  If the screen does not carry forward from the backlit but blank state, then there is an issue with the power circuit.


  1. Power down the panel, wait 30 seconds, power back on.  If still no change, ...
  2. Power down the panel and remove the processor.  Inspect 3.15A fuse in the top left corner of the CEM3 unit (labelled "F1").  If the fuse is blown, replace with the onboard spare on the right-hand side of the CEM3 circuit board.  Check the labelling on the circuit board for the fuse with the correct amperage. Also inspect the white power connector on the top left corner of the CEM3 circuit board for any damage, as well as the matching connector inside the rack.
  3. If damage is found on the connector inside the rack or on the CEM3, stop and contact an ETC dealer. If no damage is found on the connectors, replace the CEM3 into the panel and power back on.  
  4. If the CEM3 powers on properly, inspection should be made to determine the cause of the blown fuse.  Power spike, issue with incoming power, etc. This may require an electrician or ETC dealer technician. Also remember to replace the spare fuse for potential future needs.  The ETC part number for that fuse is F171-F.If the CEM3 does not power on properly after replacing the fuse, stop and contact an ETC dealer.


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