Test #1: Main Control (Acu) - Whirlpool WTW9500E SERIES Service Manual

TESTING COMPONENT
DANGER
Electrical Shock Hazard
Only authorized technicians should perform
diagnostic voltage measurements.
After performing voltage measurements,
disconnect power before servicing.
Failure to follow these instructions can result in
death or electrical shock.
Component Testing
TESTING WASHER COMPONENTS FROM THE
CONTROL
Before testing any of the components, perform the following
checks:
• The most common cause for mis-diagnosed control
failure is poor connections. Therefore, disconnecting,
inspecting and reconnecting wires will be necessary
throughout test procedures.
• All tests/checks should be made with a VOM or DVM
having a sensitivity of 20,000 ohms-per-volt DC, or
greater.
• Check all connections before replacing components,
looking for broken or loose wires, failed terminals, or
wires not pressed into connectors far enough.
• IMPORTANT: Voltage checks must be made with all
connectors attached to the boards.
• Resistance checks must be made with power cord
unplugged or power disconnected, and with wiring
harness or connectors disconnected from the control.
The testing procedures in this section may require the use
of needle probes to measure voltage. Failure to use needle
probes may damage the connectors.
IMPORTANT: Whenever the washer is tilted for service or
troubleshooting, drain water from the basket, remove any load
items in the basket, and, if equipped, remove bulk dispense
drawer.
3-4 Whirlpool & Maytag Direct Drive Top Load Washer
n
For Service Technician Use Only

TEST #1: Main Control (ACU)

This test checks for incoming and outgoing power to and from
main control. This test assumes that proper voltage is present
at the outlet.
1. Unplug washer or disconnect power.
2. Remove console to access main control.
3. Verify that ALL connectors are inserted all the way into the
main control.
4. Plug in washer or reconnect power.
5. With a voltmeter set to AC, connect black probe to J12-3
(Neutral) and red probe to J12-1 (L1).
¾ If 120 VAC is present, go to step 6.
¾ If 120 VAC is not present, check the AC power cord for
continuity (See Wiring Diagram, page 3-3.)
6. Is the "Diagnostic LED" flashing or continuously 'ON' or
'OFF'? (See Figure 1, on page 3-5 for LED location.)
¾ Flashing: (+5 VDC present and micro operating)
proceed to Key Activation & Encoder Test, page 2-3.
¾ ON: (+5 VDC present but micro failure) continue to step
9.
¾ OFF: (+5 VDC missing or micro failure) proceed to step
7.
7. Check if console UI is affecting the main control DC supply.
a. Unplug washer or disconnect power, and wait for the
diagnostic LED to turn off.
b. Remove connector J18 from main control.
c. Plug in washer or reconnect power.
d. Recheck the Diagnostic LED per step 6.
¾ If the diagnostic LED is now flashing, go to Test #4: Keys
and Encoders, "None of the indicators light up", step 4,
page 3-10. If diagnostic LED is not flashing, continue to
step 8.
8. Perform voltage checks inside header J18 on the board –
do not short pins together.
a. With a voltmeter set to DC, connect black probe to J18-3
(Circuit Gnd) and red probe to J18-1 (+5 VDC).
¾ If DC voltage is not present, go to step 9.
¾ If the DC voltage is present, but the diagnostic LED is
not flashing, continue to step 9.
9. Main Control has malfunctioned.
a. Unplug washer or disconnect power.
b. Replace the main control.
c. Reassemble all parts and panels.
d. Plug in washer or reconnect power. Perform Service
Diagnostics to verify repair.
Continue to next page for Main Control Board diagram
and Main Control Board connectors & pinouts