Did the unit work when first installed?

YES

• Is the supply okay?
  Check fuses
  Check for RED light in power supply

• Are the cables not damaged?

• Are the lenses free from marks, stickers, dirt, etc

• Is the problem intermittent or when the doors are closing?
  Are the doors still in line?
  Are the cables free from strain?

NO

• Is the voltage set correctly?

• Is the supply okay?
  Check fuses
  Check REDlight in power supply is on

• Are the indicator lights in the Transmitter and Receiver on?
  Are all cables connected?
  Are cables installed correctly and not under stress?

• Can the beams be blocked by parts of the door equipment?