Failure Investigation
for Electronic Parts
4 - 3
Failure Investigation fo
r Ele
ctro
ni
c Pa
rts
Failure Investigation fo
r Ele
ctro
ni
c Pa
rts
Main motor does not turn or Rotation speed is slow
Replace the foot controller.
N
N
When unplug the foot controller plug from the
socket of the machine and turn on the power
switch, is the resistance between pins A of the
socket 60 to 80
Ω
? (for 120V AC countries) *
1
Y
Y
* Refer to Fig.
1
.
Main motor does not turn when
pressing foot controller.
or
Rotation speed is slow.
N
Y
Does the pulley turn smoothly?
Is the sewing lamp turned on?
Refer to "5-2 Sewing lamp
does not light".
Reassemble the upper shaft
assy.
Replace the motor 3P supply
assy.
Fig.
1
A
*1 For 220 to 240V AC countries : 250 to 400
Ω
