LG WM3988H*A Service Manual page 44

7. To measure output signal voltage from the hall sensor, carefully move test
leads to terminals 1 to 4, blue and gray. Slowly rotate motor rotor by hand. You
should read a pulsing 10 Vdc. If 10 Vdc is measured from 1 to 4, move lead on
blue wire to red wire, terminal 2. Repeat rotating motor rotor by hand. You
should read a pulsing 10 Vdc from red to gray.
8. If pulsing 10 Vdc is measured from 1 to 4 and 2 to 4, hall sensor is OK! If either
test netted only 9 to 10 Vdc without changing (no pulsing) the hall sensor is
likely defective. Disconnect power by unplugging washer and ohm check hall
sensor to verify failure of the hall sensor.
- Voltage Testing Hall Sensor from the Main PCB Assembly
Test Point
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 power button. DO NOT PRESS
START!
7. Place meter leads on White & Gray wires. You should read 10 to 15 Vdc output
from the Main PCB Assembly to the Hall sensor. If no 10 to 15 Vdc 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 Vdc. Place meter leads on Red to Gray. Turn
motor rotor slowly by hand. You should measure a pulsing 10 Vdc. If both tests
measure a pulsing 10 Vdc, 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.
Test Points Result
(1) to (2)
8-12 kΩ
(1) to (3)
8-12 kΩ
(1) to (4) 10-15 Vdc
(2) to (4)
10 Vdc
(3) to (4) 10 Vdc
Remarks
Voltage Input
Pulsing Signal
Pulsing Signal
43
(4) (3)
(2) (1)