Service Manual

COMPONENT TESTING
Whirlpool & Maytag Front-Load Dryers
n
3-9
For Service Technician Use Only
ACU BOARD (FIGURE 1)
3$*(
FOR SERVICE TECHNICIAN’S USE ONLY
DO NOT REMOVE OR DESTROY
TROUBLESHOOTING TESTS
IMPORTANT: The following procedures
may require the use of needle probes
to measure voltage. Failure to use needle
probes will damage the connectors.
TEST #1: ACU Power Check
This test is used to determine if power is
present at the machine control electronics.
This test assumes that proper voltage is
present at the outlet.
1. Verify that the green LED on the ACU is lit
when the dryer is turned on.
NOTE: It is important to verify that the
system is not in “Low Power” mode. If the
HMI is working correctly, it will “wake up”
the system after powering up and pressing
Power. To verify, unplug dryer or disconnect
power for 60 seconds. Plug in dryer or
reconnect power. Press POWER. If the ACU
comes up (i.e., the green LED in the center of
the ACU flashes and then stays lit after boot-
up is complete) but the HMI does not, there
may be a problem with the HMI.
2. Unplug dryer or disconnect power.
3. Check for appropriate line voltages at the
outlet: 240VAC (electric 2-phase), 208VAC
(electric 3-phase), or 120VAC (gas).
¾If line voltage is present, go to step 4.
¾If line voltage is not present, check for
tripped circuit breaker or blown household
fuse. If CB (circuit breaker) is not tripped,
have customer check with qualified
electrician.
4. Remove top panel to access the machine
electronics.
5. ACU VAC – With voltmeter set to AC,
connect black probe to ACU J8-3 (N) and
red probe to J9-2 (L1) (see Figure 2).
Plug in dryer or reconnect power.
¾If 120VAC is present, unplug dryer or
disconnect power and go to step 6.
¾If 120VAC is not present, unplug dryer or
disconnect power and perform TEST #2:
Supply Connections, page 12.
Figure 2 - ACU Connectors & Pinouts
J2 – WIN BUS (+5VDC
and +12.7 VDC)
J2-1 RED +12.7VDC
J2-2 NC +5VDC
J2-3 YEL DATA
J2-4 BLK GND
J8 – MYST VALVE/DOOR SWITCH
J8-5 OPEN
J8-4 TAN DOOR SWITCH
J8-3 WHT NEUTRAL
J8-2 G/Y CHASSIS GND
J8-1 RED MYST VALVE
(ON SOME MODELS)
J6 – DRUM LIGHT LED
J3-3 OPEN
J3-4 OPEN
J9 – MOTOR/L1
J9-2 BLK L1
J9-1 LT BLU MOTOR
J13 – MOISTURE SENSOR
J13-1 Y/R MOISTURE SENSOR
J13-2 YEL MOISTURE SENSOR
J14 – THERMISTORS
J14-6 R/W OUTLET THERMISTOR
J14-5 OPEN
J14-4 OPEN
J14-3 R/W OUTLET THERMISTOR
J14-2 RED INLET THERMISTOR
J14-1 RED INLET THERMISTOR
J2
4
3 2 1
J8
1
2 3 4 5
J3-1 RED LED ANODE
J3-2 BLK LED CATHODE
J23 – REAR MOISTURE SENSOR
(on some models)
J23-1 BLK MOISTURE SENSOR
J23-2 RED MOISTURE SENSOR
J14
3
6
2 5
1 4
J6
3
1
4 2
J9
1
2
J13
2
1
J23
2
1
ACU CONNECTORS (FIGURE 2)
J13
J23
J2
J14
J6
J8
J9
Motor Relay
Heater-RED
L1-BLK
Heater Relay #1
(Gas & Electric)
K1
K2
K3