Brother MD-602 Service Manual page 35

Problem
2. The machine will not operate at
high speeds.
3. The machine stops while sewing.
4. The machine does not stop in the
needle down or needle up position
after the treadle is returned to the
neutral position.
Needle up position
Needle down position
Where to check (after turning off the power)
Speed adjustment knob
(2) The machine pulley does not turn
easily.
(3) The motor pulley is incorrect.
(4) The DIP switch settings are incor-
rect.
Voltage drop
Occurrence of various errors
Turn off the power switch, disconnect
the synchronizer cord, and then turn
the power switch back on. If the sew-
ing machine stops when the treadle is
at the neutral position, there is a prob-
lem with the synchronizer.
If the sewing machine does not stop,
there is a problem with the control
box.
MD-602, 612
(1) Check if the speed adjustment knob
has been turned counterclockwise.
Remove the belt from the machine
pulley and check the torque.
Check that the size of the motor
pulley being used matches the ma-
chine.
Check that the DIP switch settings
are adequate. Refer to "7.5.2 Other
DIP switch functions". If the pulley
used and the DIP switch settings
differ, the motor may continue to
rotate when stopping from a high
speed.
Check the power voltage. (Even if
the measured voltage is normal, if
the wiring is too long or if branched
wiring is used, the voltage may
drop during sewing causing the
reset function to activate and the
machine to stop.)
Refer to "13.1 Error display and de-
tails".
Replace the synchronizer.
Replace the control box.
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