Chamberlain 1270LMC - Manual (Page 6)

Assembly Step 1
Attach the T-rail to the Opener
To fasten rail, use only those screws mounted
in top of the opener. Failure to do so will cause
serious damage to the opener.
6
• Remove the two washered screws mounted in top
of opener.
• Align T-rail and styrofoam over opener sprocket.
• Cut tape from T-rail, belt and styrofoam.
• REMOVE STYROFOAM.
• Insert both washered screws through the T-rail into
the opener. Tighten both screws securely.
Remember to use only these screws! Any other
screws will cause serious damage to the opener.
• Position belt over the opener sprocket.
Washered Screw
5/16"-18x1/2"
Styrofoam
Belt
T-rail
Hole
USE ONLY THIS
TYPE AND SIZE
SCREW
T-rail
Hole
Opener
Sprocket
Belt
Washered Screw
5/16"-18x1/2"
T-rail
Hole
Assembly Step 2
Set the Belt Tension
• By hand, thread the spring trolley nut on the
threaded shaft until it is finger tight against the
trolley.
Do not overtighten.
• Insert a small screwdriver tip into one of the insert
slots of the nut ring, and hold firmly.
• Using an open end wrench at the square end,
slightly rotate the assembly clockwise until the nut
ring is released against the trolley, providing
tension for the best operation of the opener.
CAUTION
Assembly Section: Pages 6 – 7
Trolley
Threaded
Shaft
Spring
Trolley Nut
Nut
Ring
Trolley
Threaded Shaft
Screw-
driver
Nut Ring
Insert Slot
Square End Trolley
Open End
Wrench
Trolley