Bernina B 570 - Presser-Foot Micro Switch; Lower-Thread Sensor

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DRAFT – VERSION
3b Presser-foot micro switch
Is used to check presser foot micro switch
Check:
• Select test 3b.
• By lifting the presser foot, the micro- switch is activated
and the bar flashes green
• To return to section 3, press or .
Repair note:
• Check cables for deformation and/or wear and tear.
• Replace presser foot micro switch
• Replace PCBA-Base (see 4.2.4
).
3c Lower-thread sensor
Is used to check lower-thread sensor
Check:
• Select test 3c.
• Open bobbin door.
• Insert a bobbin with a very low filling of thread.
• Hold the thread and close the bobbin door.
• Slowly pull the thread.
• Signals A, B and C must change their colour to green
alternately.
• To return to section 3, press .
Tip:
Signal C might not respond if there is too much thread on the bobbin.
Repair note:
If signals A, B and C won't change their colour as described above, check these points:
• Check sensor for stains. Clean carefully if necessary.
• Repeat the test using a new bobbin.
• Check cables for deformation and/or wear and tear.
• Replace lower thread sensor.
• Replace PCBA-Base (see 4.2.4
).