The Motor Does Not Run; The Motor Does Not Run Smoothly Or It Does Not Run At A High Speed; Even After The Machine Is Started, It Stops Suddenly - Brother BL6200 Service Manual

PROBLEM
28. The motor does not
run.
29. The motor does not
run smoothly or it
does not run at a
high speed.
30. Even after the
machine is started,
it stops suddenly.
CAUSE
1. The pulley is turned too tightly.
2. The resistance between the two ends of
motor connector CN2 is not between
25 and 35 Ω.*
3. Inferior SS switch. The resistance
between pins 4 and 5 of the SS-VR
PCB unit connector should be less than
1 Ω when the SS switch is turned on
and Ω when the SS switch is turned
off.*
4. Inferior BT switch. The resistance
between pins 1 and 2 of connector CN6
(red) should be less than 1 Ω when the
BT switch is turned on and ∞ when the
BT switch is turned off.*
5. The resistance between pins 2 and 3 of
the pin jack assembly on the PCB
(F.C.) should not be less than 1 Ω when
the foot controller is not inserted.*
6. Other causes.
1. The Pulley is sometimes easy or
sometimes difficult to move when it is
rotated by hand.
2. Accumulated lint or thread under the
needle plate.
3. Improper tension in motor belt and
timing belt.
4. Tight gearing of the pattern cam gear
and worm gear.
5. The rotary shutter is dirty.
6. The motor control unit is installed
incorrectly. It is loose or slanted.
7. The voltage between pins 2+ and 3- on
the SS-VR PCB does not stay between
0 and 5 V DC when the power is turned
on and the speed adjustor is slid to the
maximum.
8. Other causes.
1. The motor control unit is installed
incorrectly. It is loose or slanted.
2. Other causes.
* Be sure to turn off the power and remove from the PCB the connector.
Adjust the mechanism so that the pulley
rotates easily.
Replace the motor.
Replace the SS-VR PCB unit.
Replace the BT switch.
*Refer to P.50.
Replace the motor control unit.
Replace the motor control unit.
Adjust the mechanism so that the pulley
rotates easily.
Clean inner rotary hook, outer rotary hook
and feed dog.
Refer to P.25.
Refer to P.27.
Clean the rotary shutter.
Install the motor control unit correctly.
Replace the SS-VR PCB unit.
Replace the motor control unit.
Install the motor control unit correctly.
Replace the motor control unit.
- 18 -
CORRECTION