Brother BAS-415 - Page 72

2. Sewing machine motor circuit board connectors
Refer to the control block diagram to check the connector locations.
Connector
Connecting point
Drive signals
Symptoms resulting from bad
No.
connection
P1
Sewing machine motor circuit 6V AC (Sewing machine motor
• Sewing machine motor does not run.
board
drive signal)
· Thread trimming is not performed.
-Power supply unit
·Overload
P2
Sewing machine motor circuit Sewing machine motor drive
· Sewing machine motor does not run.
board
signal
· Thread trimming is not performed.
-Power supply unit ·Overload
P3 Sewing machine motor circuit Sewing machine motor drive
· Sewing machine motor does not run.
board
signal · Thread trimming is not performed.
-Main circuit board
(PS)
·Overload
3. X- andY-carriage pulse motor (PMD} PCB connectors
Refer to the control block diagram to check the connector locations.
Connector
Connecting point
Drive signals
Symptoms resulting from bad
No. connection
P1
Pulse motor circuit board
Pulse motor drive signal · X-axis pulse motor does not move.
-Main circuit board
(P4)
· Y- axis pulse motor does not move.
· Pulse motor for needle bar change does not
move.
P2
Pulse motor circuit board
Pulse motor driving power
· X andY home position is not detected when
- Power supply unit
Approx. + 37V
power is turned on.
· Unbalanced pattern
· Needle bar cannot be replaced.
· Needle bar case locking
· Improper needle bar case position
P3
Pulse motor circuit board
X and
Y pulse motor drive · X andY home position is not detected when
-XV pulse motor
control power supply power is turned on.
· Unbalanced pattern
P4
Pulse motor circuit board
Drive control
power for needle · Needle bar cannot be replaced.
-Index motor
change pulse motor
· Needle bar case locking
· Improper needle bar case position
-69-
From the library of: Superior Sewing Machine & Supply LLC