Chamberlain POWER DRIVE PD752D - Manual (Page 9)

9
To avoid SERIOUS damage to garage door opener,
use ONLY those bolts/fasteners mounted in the top of
the opener.
ASSEMBLY STEP 2
Fasten the Rail to the Motor Unit
• Insert a 1/4"-20x2-1/2 bolt, washer and spacer into
the cover protection bolt hole on the back end of
the rail as shown. Install lower spacer and washer
then tighten securely with a 1/4"-20 lock nut. Do
NOT overtighten.
• Remove the bolt and lock nut from the top of the
motor unit.
• Attach spreader to the motor unit with two screws.
• Place the “U” bracket, flat side down onto the bolt
mounted on the motor unit and align the bracket
hole with the bolt holes. Fasten with the previously
removed bolt and lock nut.
• Align the rail assembly with the top of the motor
unit. Slide the rail end onto the “U” bracket, all the
way to the stops that protrude on the top and sides
of the bracket.
ASSEMBLY STEP 3
Install the Idler Pulley
• Lay the chain/cable beside the rail, as shown.
Grasp the end with the cable loop and pass
approximately 12" (30 cm) of cable through the
window. Allow it to hang until Assembly Step 5.
• Remove the tape from the idler pulley. The inside
center should be pre-greased. If dry, regrease to
ensure proper operation.
• Place the idler pulley into the window as shown.
• Insert the idler bolt from the top through the rail
and pulley. Tighten with a 3/8" lock washer and nut
underneath the rail until the lock washer is
compressed.
• Rotate the pulley to be sure it spins freely.
• Insert a 1/4"-20x1-3/4 bolt into the trolley stop hole
in the front of the rail as shown. Tighten securely
with a 1/4"-20 lock nut.
WARNING
CAUTION WARNING
WARNING
Bolt
Hex Screws
8-32x7/16
Chain
Spreader
Motor Unit
Sprocket
"U" Bracket
Lock Nut
Lock Nut
SLIDE RAIL TO STOPS
ON TOP AND SIDES
OF BRACKET
Cover
Protection
Bolt Hole
Bolt
Spacer
Spacer
Washer
Washer
Lock
Washer
3/8"
Nut 3/8"
Cable Link
Idler
Bolt
Chain and
Cable
Pulley Rail
Bolt
Nut
Washer
Trolley
Idler
Pulley
Idler
Pulley
Grease
Inside Pulley
Screwdriver
Trolley
Stop Hole
Bolt
Lock
Nut
Bolt 1/4"-20x2-1/2
Spacer Washer 5/8" Lock Nut 1/4"-20
HARDWARE SHOWN ACTUAL SIZE
Nut 3/8" Lock Washer 3/8" Idler Bolt Lock Nut 1/4"-20 Bolt 1/4"-20x1-3/4"
HARDWARE SHOWN ACTUAL SIZE