Brother b831 Service Manual page 24

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• PRESSER MECHANISM
Center of presser grooves
7 mm
1 mm
Metal bushing
Procedures
1. From the top of the arm. place presser bar guide O. presser bar lifter O. and presser bar bracket O m that order on
presser bar O as shown in the figure above.
* Make sure the tension release shaft 0 is installed in the arm.
2. Install presser bar lifter guide O and collar O (-400 type) to the arm.
3. Install presser O to presser bar O with screw Q.
* Install so that the center of the needles match the center of the grooves in presser Q.
4. Raise the presser O 7 mm from the throat plate surface. (Presser foot height differs according to the specific model.)
5. Lift presser lifter make presser bar guide O contact presser bar lifter O. and fasten with screw 0.
6. Lower presser lifter 0 and attach presser plate spring 0 to presser bar bracket O
7. Fasten screw 0 so that there is a space of 1 mm between presser bar bracket O and the metal bushing.
8. Install tension release plate 0 and tension release connecting rod 0 with two screws 0 and screw 0.
9 Install knee lift lever 0 and knee lift lever spring 0 with stud screw 0
(Attach knee lift lever spring 0 to knee lift lever 0.)
^ Presser Pressure
Adjust by turning presser adjustment screw 0.
HI THREAD WIPER
Procedures
1. Remove needle O and presser O.
2. Install thread wiper solenoid 0 with four flat screws O and washers 0.
3. Install thread wiper link 0 and solenoid link O with flat screw 0.
4. Install plunger 0 and solenoid link 0 with plunger pin 0.
* Be sure to insert rubber stopper 0
5. Attach thread wiper spring ©.
6. Install presser 0 and needle 0.
7. Install thread wiper L 0 and thread wiper R 0 with two screws 0
8. Install solenoid cover 0 with flat screw 0
9. Install the terminal pin to the 12-pin plug.
* Refer to page 37 for thread wiper adjustment.
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1 2-pin plug
Terminal pin (white)
Terminal pin (black)