Whirlpool W10254428A Manual page 13

FOR SERVICE TECHNICIAN'S USE ONLY
10. DC Supplies
+5VDC is used to power IC's and
processors on the circuit boards. If +5 VDC
was missing, the washer would become
unresponsive. To verify +5VDC ± 5%,
measure voltage at UI7 pin 7 (GND) to pin 2
(+5V [Vcc]). (Red lead to Vcc.)
+12VDC is used to actuate most of the
120VAC relays, triacs, and switches on the
CCU. If +12VDC was missing, the motors,
valves, and pumps would not turn on. To
verify +12VDC ± 5%, measure voltage
at UI7 pin 3 (–7V) to pin 2 (+5V [Vcc]).
(Red lead to Vcc.)
Troubleshooting: Refer to the wiring diagram
on page 24 when troubleshooting the DC
supplies. If +5 or +12 VDC is missing on
the CCU, unplug washer or disconnect power,
and then disconnect all components from the
CCU relying on that supply. Plug in washer or
reconnect power and check if the DC supply
has returned. If not, replace the CCU. If it has,
turn washer off and reconnect one connector
at a time until the component loading down
that supply has been identified.
11. Unplug washer or disconnect power.
12. Reassemble all parts and panels.
13. Perform the "Quick Diagnostic Test"
on pages 4–5 to verify repairs.
TEST #2: User Interface (UI)
This test is performed when any of the
following situations occurs during the
UI Component Test (see page 6):
None of the indicators or LCD turn on
Some buttons do not light indicators
No beep sound is heard
None of the indicators or LCD turn on:
1. Unplug washer or disconnect power.
2. Remove the top panel to access the CCU
and user interface (UI).
3. Visually check that ALL CCU connectors
are inserted all the way into the CCU.
4. Visually check that ALL UI connectors
are inserted all the way into the UI.
5. Visually check that the UI and housing
assembly is properly inserted into the front
console.
6. If all visual checks pass, perform TEST #1: CCU
Power Check, page 12, to verify supply voltages.
DO NOT REMOVE OR DESTROY
If supply voltages are present, replace the
user interface and housing assembly.
If supply voltages are not present, replace
the CCU.
7. Reassemble all parts and panels.
8. Plug in washer or reconnect power.
9. Perform the "UI Component Test"
(see page 6) to verify repair.
Some buttons do not light indicators:
1. Unplug washer or disconnect power.
2. Remove the top panel to access the CCU
and user interface (UI).
3. Visually check that the UI and housing
assembly is properly inserted into the front
console.
4. If visual check passes, replace the UI and
housing assembly.
5. Reassemble all parts and panels.
6. Plug in washer or reconnect power.
7. Perform the "UI Component Test"
(see page 6) to verify repair.
No beep sound is heard:
1. Unplug washer or disconnect power.
2. Remove the top panel to access the CCU
and user interface (UI).
3. Visually check that ALL CCU connectors
are inserted all the way into the CCU.
4. Visually check that ALL UI connectors
are inserted all the way into the UI.
5. If all visual checks pass, replace the UI
and housing assembly.
6. Perform the "UI Component Test"
(see page 6) to verify repair.
TEST #3: Motor Circuit
This test checks the motor, motor control unit
(MCU), and wiring.
From CCU MI3
(MCU Communications)
Figure 12 - Motor Control Unit (MCU)
To Motor
From CCU MS2
(MCU Power)
PAGE 13