Problems With Vertical Needle Movement And Reverse Stitching - Brother NX600 Service Manual

Failure Investigation for Electronic Parts
Problems with vertical needle movement
and reverse stitching
Are the resistance values for the
Stop/start switch, reverse switch,
raise needle switch and the thread
cut switch normal?
• Switch resistance values
Switch depressed ... 1 Ω or less
Switch .................. out ∞
When the upper shaft pulley is slowly
turned by hand, does the voltage
between pins 2 & 1, pins 4 &1 and
pins 5 & 1 on the main F3D PCB
assy. vary 0 – 5 V DC?
Problems with vertical needle movement and
reverse stitching
Y
Y
Is the BW switch assy. OFF?
Y
Replace main F3D PCB assy.
N
Replace SS-VR F2 PCB assy.
N
Replace NP F2 PCB assy.
N
Adjust the assembly of the
BW switch assy.
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