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©2001 Maytag Appliances Sales Company
2-5
16010486 (16008373-05)
Revised 02/01
Section 2. Washer Controls Overview
START/PAUSE INPUT
The start/pause input is selected on the
membrane switch for both washers. If
this input is initially selected the machine
control will begin the wash cycle
sequence as defined by the user input
selections. If this input is selected when a
cycle is in progress, the machine control
will pause the cycle and unlock the door
when it is safe to do so.
(Note: Machine control board is
powered up all the time. There no
longer is a line relay used, as opposed to
the MAH3000, 4000 and 5500A models.)
TACH INPUT
The tach input is a feedback signal from
the motor control. It provides eight
pulses per revolution of the switched
reluctance motor. The motor runs at 14
times the speed of the spinner (14:1 belt
ratio). The tach input is used for
monitoring speed and out-of-balance
detection (See Tachometer Circuit
Diagnostics).
If the machine control commands a motor
speed and direction but does not sense a
tach input signal within 2 or 3 seconds, it
will assign a HELP code number and
perform 10 retries. If unsuccessful, this
generally indicates a locked rotor or a
malfunction in the motor control.
If the machine control commands a coast
down from final spin speed but is still
receiving a tach input signal after two
minutes, it will log appropriate service
codes.
OUTPUT MODIFICATIONS
DEFINED
DOOR LOCK/UNLOCK
SOLENOID OUTPUT
The Door Lock/Unlock Solenoid Output
signal is a 60 millisecond pulse sent to a
solenoid in the door lock assembly. The
solenoid is attached to a lever which
moves a slider in the mechanism to lock
the door after it has been closed and the
cycle started. The solenoid has two coils,
one for locking and one for unlocking
when a pulse is directed to specific
terminals on the solenoid. Power is not
continuously applied to the solenoid,
because this would damage the solenoid.
END-OF-CYCLE SIGNAL OUTPUT
The End-Of-Cycle Signal Output is an
internal signal on the machine control
between the microprocessor and
annunciator. The end-of-cycle signal
sounds when a wash cycle is finished.
The end-of-cycle signal sounds as four
pulses on the MAH5500B and 3 pulses on
the MAH7500 in a 0.5 second intervals. If
the door is opened right at the end of the
cycle or during the end of cycle beeps,
then the signal will stop on the MAH5500B
only. If the start/pause key is pressed
near the end of the cycle, the end of cycle
signal will not occur unless the cycle is
restarted and allowed to finish. If the Off
key is pressed, the end of cycle signal will
not occur. The end of cycle signal will
occur when the door is unlocked and
ready to open on the MAH5500B. On the
MAH7500, the signal sounds then the
door is unlocked.
HEATER OUTPUT (LCD Washer only)
The machine control board turns the
heater on to heat the wash water during
the main wash until the temperature
reaches the targeted main wash
temperature. The heater is turned back
on at any point the temperature falls 5º F