LiftMaster SW470 SW490 GL BOARD Manual - Page 19

ADJUSTMENT RPM SENSOR (HALL EFFECT) ADJUSTMENT NOTE: Normally the RPM sensor (hall effect) does not need adjustment, but may go out of alignment due to shipping vibration or rough handling. WARNING To reduce the risk of SEVERE INJURY or DEATH: CAUTION • Disconnect power BEFORE performing ANY adjustments. These operators use an internal entrapment protector system. This system consists of the control board, magnet, and RPM sensor. It may become necessary to adjust the sensor for correct alignment. To do so, please perform the following steps: 1. Loosen the two screws holding the hall bracket to the frame. 2. Adjust the bracket so that the sensor is: a. Parallel with the pulley. b. .020" (.051 cm) away from the pulley's magnet. Use a feeler gauge to measure the distance. 3. Tighten screws to secure assembly. 4. Manually rotate pulley to ensure that each magnet clears the sensor board. If a magnet does not clear the board, re-adjust the RPM (hall effect) assembly accordingly. MODEL SW470 Hall Effect Cable Mounting Screw (2) AVERTISSEMENT ATTENTION Hall Effect Bracket Pulley Magnet Pulley MODEL SW490 Mounting Screw (2) Mounting Bracket Hall Effect Cable ADVERTENCIA PRECAPMuUalglenyeCt IÓN Pulley Hall Effect Magnet 19