4.4. Troubleshooting Guide / Technical Data - Bernina 1200MDA Instruction Manual

4.4. Troubleshooting Guide / Technical Data

Problem
The machine does not
sew:
Fabric does not feed
evenly
Thread breaks
6
Needles break
Skipped stitches
Poor stitch formation
Seams ß ute or wave,
especially when
sewing knits
Seams pucker
Fabric edges curl
Thread loops are too
Loose
Technical data
Stitch choice
Needle system
Seam width
Stitch length
Differential feed
Presser foot lifter
Handwheel
Sewing speed
Weight
Dimensions
Foot control model nr.
We reserve the right to make changes in the interest of technical progress.
60
Cause
• Looper or cloth plate cover is open.
• The main switch is not on.
• The machine is not plugged in.
• Differential feed is wrongly adjusted.
• Presser foot pressure is too low.
• Lower or upper knife is blunt or wrongly positioned.
• Thread tension is too tight for the thread being used.
• The machine is not threaded correctly.
• Needles are incorrectly inserted.
• Wrong needles.
• Needles are bent or blunt, points are damaged.
• Needles are not inserted correctly.
• Fabric was pulled while sewing.
• Needles are bent or blunt.
• Wrong needles used.
• Presser foot pressure is too low.
• Threads are not correctly between the tension
dials.
• Thread has got caught.
• Machine is incorrectly threaded.
• Fabric was pulled while sewing.
• Presser foot pressure is too tight.
• Differential feed is set incorrectly.
• Needle thread tension is too tight.
• Differential feed is set incorrectly.
• Too much fabric is in the stitch.
• Thread tension is too tight.
• Stitch selection lever is on roll hem.
• Too little fabric in the stitch.
2 needles, 2 loopers: 4 thread overlock with integrated safety seam
Over lock
1 needle, 2 loopers: 3 thread overlock, ß atlock roll hem
1 needle, 1 looper: 2 thread overlock, ß atlock roll hem
2 needles, 1 looper: 3 thread super stretch
130 /705 H
3-7 mm (Right needle 3/2 thread overlock)
5-9 mm (Left needle 3/2 thread overlock)
5-9 mm (4 thread overlock / 3/2 thread overlock / 3 thread super stretch)
1-4 mm
No puckering 0,7 - N
No waving or ß uting in knits N - 2
5 mm
rotates forwards
Up to 1500 s.p.m.
8.4 kg
300 (W) x 260 (D) x 290 (H) mm
YC-482 (USA and Canada only)
YC-483N (220-240V)
Solution
• Close the looper or the cloth plate cover.
• Switch machine on. (Main switch to "I")
• Insert plug into main socket.
• Check the differential feed setting.
• Adjust the presser foot pressure.
• Replace the lower or upper knife.
• Reduce thread tension.
• Check the threading.
• Insert needles fully into needle clamp with ß at
side to the back.
• Use needle system 130/705H.
• Replace needles.
• Insert needles fully into needle clamp with ß at
side to the back.
• Guide fabric gently with both hands.
• Replace the needles.
• Use needle system 130/705H.
• Increase presser foot pressure.
• Check if thread is lying between tension discs.
• Raise the presser foot and pull the thread.
• Check threading path of each thread.
• Check threading path of each thread.
• Guide fabric gently.
• Reduce presser foot pressure.
• Adjust differential feed to N - 2.
• Reduce the needle thread tension.
• Adjust differential feed to 0.7 - N.
• Reduce cutting width.
• Reduce thread tension.
• Set selection lever to overlock.
• Increase the cutting width.
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