1.     Ensure the door is fully down and the AC power cord is unplugged.

2.        Remove the four ¼-20 x 5/8 hex head bolts holding the motorhead onto the rail and place the motorhead on a platform or the ground.

3.        Replace the motorhead Driver gear. 

4.        Tie the chain onto the rail using twist ties along the length of the rail to prevent the chain from falling through the rail gap.

5.        Loosen the 2 nuts (“U” Bolt) or 1 nut (“T” Bolt) at the end of the rail (garage door end) to relieve the chain tension.

6.        Disassemble the Sprocket coupling assembly and replace the Sprocket coupling (part 18 below).

7.        Reassemble Sprocket coupling assembly.

8.        Re-tension the chain.

9.        While the motor head is disconnected from the rail, plug it in and operate it until the gear has traveled fully Counter Clockwise.  Also, ensure the chain is such that the chain latch assembly is 6 links from the “U”/”T” Bolt.  This is important!

10.     Align the Driver gear with the cogs on the Sprocket coupling prior to reattaching the motorhead.

11.     After everything is back together, check door for proper operation.  With the door in the fully open position, the red string hanging down from the rail should just be touching the lamp lens cover.

12.     Please call 888-827-3667 if there are any questions.