Friday, January 06, 2017

LG washing machine – LG WM3988H – Test mode - How to check the motor – How to check the hall sensor – door lock system – Home appliances repair and service – Test mode - How to check the motor – How to check the hall sensor – door lock system

The washer must be empty and the controls must be in the off state.
1. Press the SPIN SPEED and SOIL LEVEL buttons simultaneously.
2. Press the Power button, while the above condition. Then buzzer will sound twice.
3. Press the Start/Pause button repeatedly to cycle through the test modes.
Number of times the
Start/Pause button is pressed
Check Point
Display Status
Turns on all lamps and locks the door.
1 time
Tumble clockwise.
2 times
Low speed Spin.
rpm + Water Level
3 times
High speed Spin.
rpm + Water Temperature
4 times
Inlet valve for prewash turns on.
Water level frequency (25 >65)
5 times
Inlet valve for main wash turns on.
Water level frequency (25>65)
6 times
Inlet valve for hot water turns on.
Water level frequency (25>65)
7 times
Inlet valve for steam turns on.
Water level frequency (25>65)
8 times
Inlet valve for bleach turns on.
Water level frequency (25>65)
9 times
Tumble counterclockwise.
rpm (42>50)
10 times
Heater turns on for 3 sec.
Water temperature
11 times
Circulation pump turns on.
Water level frequency (25>65)
12 times
Drain pump turns on.
Water level frequency (25>65)
13 times
Steam Heater turns on for 1.2 sec.
TSG temperature
14 times
Water level Sensor for Steam
Water level frequency of TSG (0>255)
15 times
The Door Lock Switch Assembly consists of a Heating PTC, a Bimetal, a Protection PTC, and a Solenoid. It locks the door during a wash cycle.
1.Operation for door closing
# After the system turns on, PTC heating starts up through terminal 2 > 4’s 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.
(2) to (4) > 700-1500 Ohm At 77degree F (25 degree C)
(3) to (4) > 60-90 Ohm At 77degree F (25 degree C)
(4) to (5) > Infinity
(2) to (4) > 120 Vac  Voltage Input
Wring diagram 
The DD 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.
(1) to (2) > 5-15 Ohm
(2) to (3) > 5-15 Ohm
(3) to (1) > 5-15 Ohm
The hall sensor determines the speed and direction of the motor.
It also can read that the load is off balance when the drum speed fluctuates.
If measuring voltage from the Main PCB Assembly to the Hall Sensor, use the following steps:
1. Unplug power cord.
2. Remove rear washer panel.
3. Locate Hall sensor connector on the stator behind the rotor.
4. Place meter leads on terminals 5 to 4, white to gray.
5. Plug in power cord, close door, and press power button.
6. You should measure 10 to 15 Vdc. If 10 to 15 Vdc is present, control board, white wire, and gray wire are OK! If not follow testing output voltages on control board in next section.
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.
1) Construction of steam generator
Inlet valve that controls supplying water, Water level sensor that sense amount of water supply, Thermistor ASSEMBLY the sense inner temperature of Steam generator, Heater ASSEMBLY that heats water supply, Steam generator CASE that is container of water supply, nozzle and hose of water supply.
2) Operation mechanism of Steam generator
After supplying some amount of water through inlet valve and water level sensor, Heater operates and steam generates. Generated steam is sprayed by nozzle. If the water in the steam generator is reduced by spraying steam, water level sensor decide to supply water or not.
3) Operation method of Steam generator
The Steam Generator Assembly is supplied as an assembly only; parts like the water level sensor, thermistor, or heater cannot be replaced individually. Diagnosis is limited to determining malfunction and replacing as an assembly. The steam generator does not have to be removed from the machine to be drained. Be sure to let the water cool to avoid a burn. Have a hose available to slip onto the connector or a large towel to catch the water so it doesn’t run down into the machine cabinet. If you remove the steam generator before draining it, be sure to avoid tipping it and spilling the water.