Brother MFC-J3520 Service Manual page 226

(5) Remove the one screw (TAPTITE CUP S M3x6) from the CR frame ASSY.
Assembling Note: Tighten the screw (TAPTITE CUP S M3x6) temporarily and then
1) Mount the Head/carriage unit and CR timing belt to the CR frame ASSY.
2) Tighten the one screw (TAPTITE CUP S M3x6) firmly.
(6) Remove the Belt tension spring from the CR frame ASSY.
CR frame ASSY
perform the following procedures before mounting the Upper cover.
Belt tension spring
Fig. 3-124
3-106
TAPTITE CUP S M3x6
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