Console And Indicators; Automatic Temperature Control; Water Level And Pressure Transducer Calibration - Maytag MVWB850WQ Service Manual

FOR SERVICE TECHNICIAN ONLY – DO NOT REMOVE OR DESTROY
6. Visually check that the P5 and P10 connectors are
inserted all the way into the machine/motor control.
With an ohmmeter, verify resistance values as
shown below:
Check
Resistance Go to
between
values step 7 if
connector
should be: values are:
pins
1-2
Much higher
P5 31 Ω ± 5 Ω
than 31 Ω
1-3
6-5 Much higher
or much
6-4
1.5 kΩ ± 100 Ω
lower than
P10
6-3
1.5 kΩ
1-7 600 Ω to 21.2 kΩ Out of range
7. Tilt washer forward to access the bottom of the
washer and the drive motor area. See figure 1,
page 14. Remove the motor bolt, then the motor
cover to access the motor connections. See figure 2,
page 14.
8. Visually check the mounting bracket and electrical
connections to the motor and rotor position sensor
board.
If visual check passes, go to step 9.
If visual check fails, reconnect the electrical
connections, reassemble stator and motor cover,
and repeat step 1.
9. With an ohmmeter, check for continuity between all
pins on the P10 machine motor control connector
and the motor rotor position sensor (RPS) connector.
See figures 2 and 5, pages 14 and 15.
If there is continuity, check the motor windings.
If the motor windings are open, replace the drive
motor.
If there is no continuity, replace the lower machine
harness.
10. With an ohmmeter, check for continuity between all
pins on the P5 machine/motor control connector
and the drive motor connector.
If there is continuity, replace the drive motor.
If there is no continuity, replace the lower
machine harness.
11. The drive motor and lower harness are good.
Replace the motor RPS board and perform the
Diagnostics test in step 1 to verify repair.
12. If the Diagnostics motor test in step 1 failed, then
the machine/motor control has failed:
Unplug the washer or disconnect power.
Replace the machine/motor control assembly.
Perform the Motor Diagnostics in step 1 to verify
repair.
TEST #4 Console and Indicators
This test is performed when any of the following
situations occurs during the Console and Indicators
Diagnostic Test, page 2:
 None of the indicators light up
 No beep sound is heard
 Some buttons do not light indicators
None of the indicators light up:
1. Perform steps in Accessing & Removing the
Electronic Assemblies, page 6 and visually check that
the P7 connector is inserted all the way into the
machine/motor control.
2. Visually check that the user interface assembly is
properly inserted in the console assembly.
3. If both visual checks pass, replace the user interface
assembly.
P A R T N O . W 10093831A
4. Plug in washer or reconnect power.
5. Follow procedure under Activation of Console and
Indicators Diagnostic Test mode, page 2 to verify repair.
6. If indicators still do not light, the machine/motor
control has failed:
Go to
Unplug washer or disconnect power.
step 12 if:
Replace the machine/motor control assembly.
Plug in washer or reconnect power.
Activate the Console and Indicators Diagnostic
Resistances
Test mode, page 2 to verify repair.
at all
connectors
No beep sound is heard:
are correct
It is possible to turn the feedback sound ON and OFF
from the User Interface buttons.
1. Press and hold the END SIGNAL button for more
than 5 seconds. After the setting has been modified,
an acknowledge beep will be generated.
2. Release the END SIGNAL button and press
any button.
If no beep sound feedback is heard, continue
with step 3.
3. Perform steps in Accessing & Removing the
Electronic Assemblies, page 6 and visually check
that the P7 connector is inserted all the way into
the machine/motor control.
If visual check passes, replace the user interface
assembly.
4. Plug in washer or reconnect power.
5. Follow procedure under Activation of Console and
Indicators Diagnostic Test mode, page 2 to verify repair.
6. If replacing the user interface assembly failed:
Unplug washer or disconnect power.
Replace the machine/motor control assembly.
Plug in washer or reconnect power.
Activate the Console and Indicators Diagnostic
Test mode, page 2 to verify repair.
Some buttons do not light indicators:
1. Perform steps in Accessing & Removing the
Electronic Assemblies, page 6 and visually check
that the console electronics and housing assembly
is properly inserted into the front console.
If visual check passes, replace the user interface
assembly.
2. Plug in washer or reconnect power.
3. Follow procedure under Activation of Console and
Indicators Diagnostic Test mode, page 2 to verify repair.
TEST #5 Automatic Temperature Control
This test checks the water inlet valves, the temperature
sensor, and the machine/motor control.
1. Check the valves by performing Test #2, page 4
before continuing to the next step.
2. Ensure proper hose connections and that
household's hot water is present.
3. Plug in washer or reconnect power.
4. Remove all clothes from the washer.
5. Select POWER/CANCEL wash cycle NORMAL
Wash/Rinse Temp. WARM/COLD START/PAUSE.
6. After the tub fills and starts to wash, stop the washer.
7. Measure the water temperature, and verify it is
85°±10°F (29°±6°C).
If the water temperature is correct, ATC is
functional.
If the water temperature is incorrect, then go to
step 8.
POUR LE TECHNICIEN SEULEMENT – NE PAS ENLEVER NI DÉTRUIRE
P A G E 5
8. Close the inlet water faucet and disconnect the hoses
from the washer. Using a container, open the water
faucet and verify that there is hot water available and
that the hoses were not installed in reverse.
9. Unplug washer or disconnect power.
10. Access the machine/motor control assembly. See
Accessing & Removing the Electronic Assemblies,
page 6.
11. Remove the P9 connector, and using an ohmmeter,
measure the resistance between pins P9-1 and
P9-3. Verify that the resistance is within range as
shown in the following table:
THERMISTOR RESISTANCE
Temperature Resistance ( )
32°F (0°C) 32.6–34.2 kΩ
40°F (4.4°C) 26–27.5 kΩ
50°F (10°C) 19–20.5 kΩ
60°F (16°C) 15–15.7 kΩ
70°F (21°C) 11.7–12.2 kΩ
80°F (27°C) 9.1–9.5 kΩ
90°F (32°C) 7.2–7.6 kΩ
100°F (38°C) 5.6–5.9 kΩ
110°F (44°C) 4.6–4.9 kΩ
120°F (49°C) 3.6–3.8 kΩ
130°F (55°C) 2.9–3.1 kΩ
If the resistance is within the range shown in the
table, go to step 12.
If the resistance is infinite or close to zero, replace
the log valve assembly.
12. Replace the machine/motor control assembly.
See Reinstalling the User Interface Printed Circuit
Assembly Board, page 6.
TEST #6 Water Level and Pressure
Transducer Calibration
This test checks the water level sensing components,
and calibrates the pressure sensor.
1. Unplug washer or disconnect power.
2. Access the machine/motor control assembly. See
Accessing & Removing the Electronic Assemblies,
page 6.
3. Check hose connection between the pressure
transducer on the machine/motor control and the
pressure dome attached to the tub. Check to ensure
hose is routed correctly in the lower cabinet and not
pinched or crimped by the back panel.
4. Plug in washer or reconnect power.
5. Remove all clothes from the washer.
6. Drain the tub until all water has been removed.
7. Calibrate the pressure transducer:
See Activation of Manual Diagnostic Test Mode,
page 2, and perform steps 1 and 2 until the
000
display shows and the Add A Garment
indicator LED is flashing.
Press and hold the END SIGNAL button until a
single beep sounds, and the display shows "Pt"
to indicate zero calibration has completed.
Exit Diagnostic: Manual by pressing POWER/
CANCEL.
8. Select POWER/CANCEL wash cycle NORMAL
START/PAUSE.
9. Verify that the tub fills to the top of the impeller plate.
P È I C E
o
N W10093831A