LG WM1873FDS Service Manual ▷ View online
37
FOR AUTHORIZED SERVICE TECHNICIAN
9-3. STATOR ASSEMBLY
Wiring
diagram
Circuit in the MAIN PWB / Wiring Diagram
MAIN PWB
MICOM
Ha
12V
NA1NA
WH
WH
GND
MO
TO
R
Hb
Ha
RD
RD
BL
BL
GY
YL
w
w
v
u
v
u
BL
RD
RD
RD4
IPM
GY
YL
w
u
v
BL
RD
1
1 1
2
3
4
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
3
2
2
1
3
4
1
2
3
4
5
1
2
3
4
5
2
3
4
1
2
3
4
Hb
Function
Test points
(Windings)
Result
(Windings)
The Direct Drive motor can be driven from stopped to maximum speed in infinite
steps in either direction.
There are 36 poles on the stator; 12 permanent magnets spaced around the rotor.
There are no brushes to wear out. Unlike a more traditional brushless motor, the
rotor surrounds the stator rather than being attached to it.
Test Points
Result
(1) to (2)
(2) to (3)
(3) to (1)
(2) to (3)
(3) to (1)
5-15 Ω
5-15 Ω
5-15 Ω
5-15 Ω
5-15 Ω
WINDINGS
HALL SENSOR
(1) (2)
(3)
38
FOR AUTHORIZED SERVICE TECHNICIAN
Test Point
and
Result
and
Result
(Hall
Sensor)
1. Unplug power cord.
2. Remove rear panel.
3. Remove washer top.
4. Remove main PCB assembly cover as shown in figure below.
5. Locate the white hall sensor 4-wire connector using wiring diagram wire colors
as your guide.
6. Plug in power cord, close door, and press the button. DO NOT PRESS START!
7. Place meter leads on White & Gray wires. You should read 10 to 15 V
DC
output
from the Main PCB Assembly to the Hall sensor. If no 10 to 15 V
DC
is
measured, the control board is defective.
8. Place meters leads on Blue to Gray. Turn motor rotor slowly by hand. You
should measure a pulsing 10 V
DC
. Place meter leads on Red to Gray. Turn
motor rotor slowly by hand. You should measure a pulsing 10 V
DC
. If both tests
measure a pulsing 10 V
DC
, hall sensor and harness OK. If either or both tests
measures 9 to 10 volts, but does not pulse or change, Hall sensor has failed
and must be replaced. IF zero (0) voltage is measured on either test, check red
blue wires for continuity. Repair or replace harness as needed.
- Voltage Testing Hall Sensor from the Main PCB Assembly
Test Points
(1) to (2)
(1) to (3)
(1) to (4)
(2) to (4)
(3) to (4)
(1) to (3)
(1) to (4)
(2) to (4)
(3) to (4)
Result
8-12 k
8-12 k
8-12 k
10-15 V
DC
10 V
DC
10 V
DC
Remarks
Voltage Input
Pulsing Signal
Pulsing Signal
Pulsing Signal
(1) (3)
(2) (4)
39
FOR AUTHORIZED SERVICE TECHNICIAN
9-4. PUMP MOTOR ASSEMBLY
Wiring
diagram
Circuit in the MAIN PWB
Wiring Diagram
MICOM
IC
R
5V
Rg
Cg
Vdc
Rs
Cs
PCB
CONNECTOR
PUMP
Vac
2
1
4
3
Pump Driving circuit
MAIN PWB
NA2
1 2 3
1 2 3
3 2 1
3 2 1
1 2 3
4
1 2 3 4
BL3
SB
SB
SB
BK
BN
BN
DRAIN
PUMP
CIRCULATION
PUMP
BK
Object
Function
Test
points
Result
* Each circuits of loads in wiring diagram are all same.
Two pump motors are used to drain the tub and to circulate the water / detergent solution.
Drain Pump
Drain Pump
Circulation Pump
Circulation Pump
Test Points
Result
(1) to (2)
10-20 Ω
Test Points
Result
(1) to (2)
18-30 Ω
T.P
For Drain
For Circulation
(1)(2)
(2)
(1)
(1)
(2)
40
FOR AUTHORIZED SERVICE TECHNICIAN
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