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) indicates something that you must do. The picture inside the circle indicates the · · · · · nature of the thing that must be done. (For example, the symbol at left means “you must make the ground connection”.) T-8420B, 8450B, 8720B, 8750B...
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Furthermore, do not drink the oil or eat the grease under any circumstances, as they can cause vomiting and diarrhea. Keep the oil out of the reach of children. T-8420B, 8450B, 8720B, 8750B...
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If Use only the proper replacement parts as specified only one hand is used, the weight of the machine by Brother. head may cause your hand to slip, and your hand may get caught. T-8420B, 8450B, 8720B, 8750B...
1. Clear away any tools, etc. which may be near the table holes. 2. While holding the face plate with your left hand, gently return the machine head to the upright position with your right hand. 2872M T-8420B, 8450B, 8720B, 8750B...
Tap the head rest (3) securely into the table hole. If the head rest (3) is not pushed in as far as it will go, the machine head will not be sufficiently stable when it is tilted back. 2960M T-8420B, 8450B, 8720B, 8750B...
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(5) is at the desired position within a distance of 13 mm of the needle plate when the knee liter plate (1) is fully pressed. 9. After adjustment is completed, securely tighten the nut (9). Within 13 mm 2963M T-8420B, 8450B, 8720B, 8750B...
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10-14 mm of deflection in the V-belt (1) when it is pressed at the midway point with a force of 5 N. 2966M 9. Belt cover bracket (1) Belt cover bracket (2) Screws [2 pcs] Ground wire 2967M T-8420B, 8450B, 8720B, 8750B...
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2968M (1) Belt cover U (2) Screws [4 pcs] Insert the projecting part underneath the machine pulley. 2969M 11. Belt cover D (1) Belt cover D (2) Wood screws [2 pcs] (3) Washers [2 pcs] 2970M T-8420B, 8450B, 8720B, 8750B...
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(1) Belt cover D lid 2972M Pull belt cover D (2) forward to adjust so that there is no gap between belt cover U (3) and the belt cover D lid (1). 2973M Re-tighten the wood screws. 2974M T-8420B, 8450B, 8720B, 8750B...
14. Cotton stand (1) Cotton stand NOTE: Securely tighten the nut (4) so that the two rubber cushions (2) and the washer (3) are securely clamped and so that the cotton stand (1) does not move. 2878M T-8420B, 8450B, 8720B, 8750B...
(4) of the oil gauge window (3). 3. Replace the rubber cap (1). * If the lubricating oil level drops below the bottom reference line (5), be sure to add more oil. 2978M T-8420B, 8450B, 8720B, 8750B...
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Apply 1 - 2 drops of oil to the places indicated by the arrows. <Minimum lubrication type only> * Do not apply oil for semi dry types. <T-8450B, 8750B> 2885M <Semi dry type and minimum lubrication type> Rotary hook race (left and right) 2979M T-8420B, 8450B, 8720B, 8750B...
(2) GREASE indicator (red) If the GREASE indicator (2) illuminates and the buzzer sounds each time the treadle is depressed, it is time to apply 2981M grease. (See P. 30.) T-8420B, 8450B, 8720B, 8750B...
3. Insert the needle (2) straight in as far as it will go so that the long groove is facing inward, and then securely tighten the screws (1). Long groove 2894M <T-8450B, 8750B> Long groove 3125M T-8420B, 8450B, 8720B, 8750B...
1. Open the slide plates (1) by moving them to the right and left. 2. Lift up the latch (2) of the rotary hook, and then remove the bobbin case (3). 3. Remove the bobbin. 3001M T-8420B, 8450B, 8720B, 8750B...
* Loosen the screw (5) and move the bobbin presser (6) to adjust the amount of thread wound onto the bobbin. NOTE: More thread The amount of thread wound onto the bobbin should be a maximum of 80 % of the bobbin capacity. Less thread 2123M 2124M T-8420B, 8450B, 8720B, 8750B...
5. Pull out the thread to a length of approximately 50 mm. 6. Close the slide plates. Use bobbins (1) made of light alloy as specified by BROTHER. 2983M 2900M T-8420B, 8450B, 8720B, 8750B...
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3. Insert the bobbin case (2) into the rotary hook. 4. Push latch (9) of the rotary hook flat. 5. Close the slide plates. Use bobbins (1) made of light alloy as specified by BROTHER. 3126M <C> 3127M 2999M T-8420B, 8450B, 8720B, 8750B...
・ Turn the machine pulley and raise the thread take-up (1) before threading the upper thread. This will make threading easier and it will prevent the thread from coming out at the sewing start. ・ Thread the left-side thread first. T-8420B, 8450B, 8720B, 8750B...
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・ Operate the lifting lever or the knee lifter to raise the presser foot. The thread can be passed securely in between the tension discs. <T-8420B, 8720B> <T-8450B, 8750B> Pass the thread on the inside of the tab (3). T-8420B, 8450B, 8720B, 8750B...
(2). * Check that the stitch length dial (2) does not rotate. Locked Unlocked 2985M 5-7. Using the knee lifter The presser foot (2) can be raised by pressing the knee lifter plate (1). 2907M 2908M T-8420B, 8450B, 8720B, 8750B...
The number of stitches of the outer needle varies according to the combination of sewing angle and stitch length. [Example] For a sewing angle of 40° and a stitch length of 2.9 mm, the number of stitches becomes 6. T-8420B, 8450B, 8720B, 8750B...
4. Depress the treadle to start sewing. Lower thread Lower thread 2915M 6- 2. Backtacking When the reverse lever (1) is pressed during sewing, the feed direction will be reversed. When it is released, the feed direction will return to normal. 2986M T-8420B, 8450B, 8720B, 8750B...
(Condensed stitches are sewn while the reverse lever (1) is being pressed.) * To stop sewing condense stitches and return to using the backtack function, lower the stopper (5) so that it does not touch the reverse stitching lever plate (6). 2989M T-8420B, 8450B, 8720B, 8750B...
After the lower thread tension has been adjusted, adjust the upper thread tension so that a good, even stitch is obtained. 1. Lower the presser foot. 2. Adjust by turning the tension nut (2). Becomes stronger Becomes weaker Becomes weaker Becomes stronger 2924M T-8420B, 8450B, 8720B, 8750B...
・ When sewing with a stitch length of 2 mm or less ・ When sewing under any of the above three conditions and you would like to prevent skipped stitches, thread 2929M tightening problems such as looping, or thread breakages T-8420B, 8450B, 8720B, 8750B...
<Checking> 1. Replace the needle if it is bent or if the tip is broken. 2. Check that the upper threads have been threaded correctly. (Refer to page 19.) 3. Carry out a test sewing. 2992M T-8420B, 8450B, 8720B, 8750B...
1. Tilt back the machine head. 2. Pour lubricating oil into the oil cover (1) until the oil level reaches the reference line (2). (Refer to p.11.) 3. Return the machine head to its normal position. 2993M T-8420B, 8450B, 8720B, 8750B...
If this happens, apply grease and then reset the alarm display by referring to the procedure on the following page. * If you continue to use the sewing machine after carrying out the reset procedure but without applying grease, problems with the sewing machine may result. T-8420B, 8450B, 8720B, 8750B...
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・ When using the grease again, remove any old grease from inside the nozzle first. (Store the tube away carefully once the tube has been opened, otherwise the grease remaining inside the tube may deteriorate, and this may affect its lubricating performance.) 2937M T-8420B, 8450B, 8720B, 8750B...
30 seconds, and then carry out the reset procedure again. ・ The RESET switch (1) should never be pressed except when carrying out the reset procedure after grease application. T-8420B, 8450B, 8720B, 8750B...
* Turn the adjusting screw (1) and check the lubrication amount repeatedly until the lubrication amount is correct. 4. Check the lubrication amount again after the sewing machine has been used for approximately two hours. 3000M T-8420B, 8450B, 8720B, 8750B...
Pull out the lower thread to check that there is no slackness in the thread tension, or replace the bobbin or bobbin case. Is the thread take-up amount too large? Adjust the thread take-up amount. 0977M T-8420B, 8450B, 8720B, 8750B...
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If sewing light or medium-weight materials, is a presser foot with slots on the underside or grooved feed dog being used? Use a presser foot without slots. Use a feed dog without grooves. Grooves Slot 2946M 2944M T-8420B, 8450B, 8720B, 8750B...
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Is the bobbin turning smoothly? If the bobbin is not turning smoothly, replace the bobbin. Is a bobbin other that the light-alloy bobbins specified by Brother being used? Use only bobbins which are specified by Brother. 17-18 2951M 2124M T-8420B, 8450B, 8720B, 8750B...
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0469M The GREASE indicator on This is a notification that it is time to apply grease. alarm display Apply grease to the sewing machine. illuminates and the buzzer sounds when the treadle is depressed. T-8420B, 8450B, 8720B, 8750B...
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