Control Board Illustrations - Chamberlain LiftMaster Professional SW420 Manual

C O N T R O L B O A R D I L L U S T R A T I O N
J1 Connector
J2 Connector
J5 Connector
SAMS
J4 Connector
Master/Second
Relay Drive
Troubleshooting LEDs
J1 Terminal
Troubleshooting LEDs
21
Dip Switch #4
Master/Second
Potentiometer
Timer to Close
Potentiometer
Force Adjustment
Dip Switch #2
Dip Switch #1
Diagnostic
LED
Limit
LEDs
Programming
Port
(factory use only)
Motor Learn
Button
J3 Connector
Aux. Relay Drive
(not used)