Section 3. Output Modifications Defined; Section 4. Revised Door Lock Operation - Maytag MAH21PD Supplemental Service Instructions

SECTION 3. OUTPUT MODIFICATIONS
DEFINED
DOOR LOCK/UNLOCK SOLENOID OUTPUT
The Door Lock/Unlock Solenoid Output
signal is a 60 millisecond pulse sent to a
push-pull solenoid in the door lock
assembly. The solenoid is attached to a
lever which moves a slider in the
mechanism to lock the door. The solenoid
has two coils, one for locking and one for
unlocking. Power is not continuously
applied to the solenoid.
SECTION 4. DOOR LOCK
Revised Door Lock Operation
When the door is closed, the hoop on the
door enters the opening at the bottom of
the door lock assembly and meshes with
fingers on the rotating cam. As the cam is
rotated back past center a strong spring
toggles the cam to the back thus drawing
the door tightly closed. At the same time,
the door inner liner presses an actuator
button on the door lock assembly. This
actuator causes a rocker arm to release the
door switch button. The door switch
(which is a single pole, double throw
switch) toggles to the door-closed position.
At this time nothing further happens until a
cycle is started.
When a cycle is started the main control
board will first energize the wax motor (it
is located at the right side of the door lock
assembly). The wax motor operation does
not cause the door to lock. Its' main pur-
pose is to assure release of the door lock in
the event of a power failure.
Approximately two minutes after the door
is closed and a cycle is started the control
sends a very short pulse of 120 volt AC to
the door-locking coil of the dual solenoid.
The solenoid pulls an actuator arm which in
turn pushes a slider to the right to block
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the rotating cam (which locks the door)
and as the actuator arm moves it also
actuates the spin enable (door-locked)
switch.
One of the new features on the MAH21
control is a "notification" to the user when
the door is not locked for any reason. The
words "DOOR LOCKED" in the display will
blink rapidly or "flutter". A D17 will be posted
in the fault codes as well.
The door lock sequence will be repeated for
a number of times (up to seven) in an at-
tempt to lock the door. Should that fail, the
cycle will be paused and "RESELECT
CYCLE" will be posted in the display. The
wax motor will be released and will cool. As
the wax motor cools its' piston will be drawn
back which will result in the door lock slider
being pushed back to the left and to the
unlocked position.
At the end of the cycle, as the coast-down
from spin begins, the wax motor is released
and begins to cool. After the "shake-out
sequence" of reverse tumble, the control
sends a short 120 volt AC pulse to the door
release coil. The door release coil will push
the solenoid armature back out which will
push the actuator arm back to the unlocked
position. This pulls the slider away from the
rotating cam and releases the spin enable
switch (door-locked switch). The door may
then be pulled open.
Depending on how quickly the wax motor
cools, the actual release of the door can be
from either the wax motor or the door re-
lease solenoid.
If a door lock solenoid fails the door of
course would not lock; the spin enable
switch would not be made. After several
attempts to lock the door fail the display
would "flutter' the "DOOR LOCKED" display
and then would pause the cycle.
RESELECT CYCLE would be displayed.
©2002 Maytag Appliances
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