LG WM1873FDS Service Manual ▷ View online
33
FOR AUTHORIZED SERVICE TECHNICIAN
LIQUID DETERGENT/SOFTENER/
BLEACH DOES NOT FLOW IN
ABNORMAL SOUND
Is water supplied?
Yes
No
Are the plugs correctly
connected to the terminals of
the INLET VALVE
ASSEMBLY?
Is the motor bolt loosened?
Is the liquid detergent/
softener/bleach cap clogged?
Check the
wiring on the
dispenser.
Refer to
NO WATER
SUPPLY.
No
Is liquid detergent/softener/
bleach put in the correct
compartment of the drawer?
Put it in the
correct
compartment.
Clean the cap
and
container.
No
Yes
Yes
Yes
Secure the
bolt.
Is there friction noise coming
from the motor?
Check hall
sensor.
Replace If
defective.
Then check
stator.
Replace if
necessary.
Check rotor
for broken
magnets.
Replace rotor
if necessary.
Yes
No
Yes
(1) Liquid chlorine Bleach Compartment
(2) Liquid fabric Softener Compartment
(3) Prewash Compartment
(4) Main Wash Compartment
Prewash
Hot water
Main wash
bleach
Dry
(1)
(4) (3)
(2)
Bleach cap
Softener
cap
Liquid detergent cap
34
FOR AUTHORIZED SERVICE TECHNICIAN
9. COMPONENT TESTING INFORMATION
9-1. FILTER ASSEMBLY (LINE FILTER)
When Resistance (Ohm) checking the Component, be sure to turn the power off,
and do voltage discharge sufficiently.
WARNING
Wiring
diagram
Circuit in the MAIN PWB / Wiring Diagram
Vac
MAIN PWB
ASSEMBLY
FUSE
RD1
WH1
LI
L2
RI
CI
C2
C3
3
2
1
3
2
1
Test
points
and
Result
and
Result
Test Points
Result
WH (1) to RD (3)
WH (3) to RD (1)
WH (3) to RD (1)
0 Ω
0 Ω
0 Ω
(3)
(1)
WH1
(3)
(1) RD1
35
FOR AUTHORIZED SERVICE TECHNICIAN
9-2. DOOR LOCK SWITCH ASSEMBLY
Wiring
diagram
Circuit in the MAIN PWB / Wiring Diagram
MAIN PWB
Vdc
Vac
MICOM
12V
4 1
3 2
4 1
3 2
Relay
Relay
NA4
1
2
3
4
1
2
3
4
2
3
4
PT
C
PT
C
Door switch
SOLENOI
D
5
YL
BL
RD
BK
AC
Common
terminal
of valve
Function
The door lock switch assembly consists of a heating PTC, a bimetal,
a protection PTC, and a solenoid. It locks the door during the wash cycle.
1.Operation for door closing
- After the system turns on, PTC heating starts up through terminals 2 and
4 authorizing the power on.
- After PTC heating starts up and before solenoid operation is driven,
force the system to the off position through CAM.
Door close
- Authorizing one impulse through terminal 3~4 (PTC & solenoid) will
make the door locked.
- Door lock is detected when switches in terminal 4~5 are set closed.
CAM rotation will forcibly clear off the connection.
The maximum, allowable number of impulse authorizations is 2.
Upon the third authorization of the impulse, the position of CAM goes
back to the door-open position.
- Authorizing the impulse occurs in 4.5 seconds upon input for max
performance and two authorization processes are allowed at most.
Normal operation period of PTC heating: 1.5 – 5 seconds.
(Defects from the development process.)
2.Operation for door opening
- With a temporary stop, door automatically opens by CAM rotations after
authorizing the impulse from the terminal, 3 ~ 4 and the power turns
off – maximum of 3 times of the authorizing period.
- Upon the fourth authorization of the impulse, the position of CAM goes
back to the door-close position.
36
FOR AUTHORIZED SERVICE TECHNICIAN
Test
points
Result
Test Points
(2) to (4)
(3) to (4)
(4) to (5)
(2) to (4)
(3) to (4)
(4) to (5)
(2) to (4)
Result
700-1500 Ω
60-90 Ω
Infinity
120 Vac
Remarks
At 77
°F
(25
°C
)
At 77
°F
(25
°C
)
Voltage Input
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