Pulse Motors Do Not Return To Starting Point - Baby Lock BLSY Service Manual

Failure Investigation for Electronic Parts Pulse motors do not return to starting point
When the power is turned ON, the pulse motors do not return to the
starting point.
• When needle is up : Z pulse motor returns to its original position.
• When needle is down : F and S pulse motors return to their original position.
• Regardless of needle position, AT, PF, and C pulse motors return to their original
position.
Are the main PCB and PF, and AT
initial sensor PCB assemblies
correctly connected?
When the slit section of each initial
sensor PCB assembly is switched
to the open / closed position with
the power on, does the voltage
between pins 2 and 3 on the main
PCB assemblies (CN28, and CN7)
change between 0 - 3.3 V DC?
Y
Y
To next page
N
Connect it properly.
N
Replace the initial sensor
PCB assembly.
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