Maytag MDG9700A Technical information

27” Gas Dryer⎯Technical Information
MDG9700A *
• Due to possibility of personal injury or property damage, always contact an authorized technician for servicing or
repair of this unit.
• Refer to Service Manual 16025911 for detailed installation, operating, testing, troubleshooting, and disassembly
instructions.
!
CAUTION
All safety information must be followed as provided in Service Manual 16025911.
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
Model
Power Source
Voltage AC
Frequency
Amperage
Motor Horsepower
Cabinet Dimensions
Height
Width
Depth
Features
Cycles
Controls
Air Fluff
Wrinkle Release
Wrinkle Prevent
Tumbler
End of Cycle Chime
Drum Light
Freshen Up Cycle
Drying Rack
Weight lbs.
Uncrated
March 2005
©2005 Maytag Services
MDG9700A*
120VAC
60 Hz
30 A
1/3
38”
27”
30.75”
16
LED
X
X
X
Stainless
X
X
X
X
138
1
16026117 Rev. 0
Troubleshooting
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
Will Not Run
Will not start or run:
• All wires are hooked up to their corresponding
terminals.
• Dryer is plugged in.
• Blown fuse or circuit breaker.
• Door switch functional...door closed. Check for
error code 3 (See Table for code definition).
• Start/Pause rotary selector dial functional.
• Control Board operational.
• Drive motor functional.
• Check motor winding resistance: 2.88ohms
between pin #3 and 4, 3.5ohms between pin #4
and 5.
Motor runs/ tumbler will not turn:
• Belt off or broken/damaged.
• Idler tension spring too weak or stretched.
• Idler pulley jammed or stuck.
Runs a few minutes and then stops:
• Lint buildup around drive motor.
• Low voltage present.
• Blower impeller blocked in blower
• housing.
• Drive motor - start switch contacts stuck closed.
Will Not Dry Gas Models
Poor Gas Ignition
When the dryer is operated on a heat setting, the igniter
should be energized and burner shall fire within 45
seconds at 120 VAC. The failure of a component in this
system will usually be indicated by one of three
symptoms:
The igniter does not glow. If the igniter does not heat
up, remove power and using an ohmmeter, check the
following:
• Open flame sensor
• Open igniter
• Shorted booster coil
• Open wiring
• Bad motor switch (Neutral supply)
• No power from control (L1 supply)
Igniter glows - No gas ignition. If the igniter heats up
but the main burner flame is not ignited, remove power
and using an ohmmeter, check the following:
• Open secondary coil
• Open holding coil
• Open wire harness
• Stuck flame sensor (Stuck closed)
The gas is ignited but the flame goes out. If a normal
ignition takes place and after a short while the flame
goes out, check for the following:
• Radiant sensor contacts opening
prematurely.
• Weak gas valve coil may open when
stressed by higher temperatures.
• Weak Hi-Limit
• Poor venting
• Bad drum seals
Blows fuses or trips circuit breaker:
• The amperage readings are at 240 volts. One
line will be 24 amps and the other line will be 21
amps. The neutral line will be at 3 amps. If the
above amperages are present, then the house
wiring, fuse box or circuit breaker should be
suspect.
Improper drying/clothes wrinkled/ rough texture/long
• Shorted heating element to housing.
dry time:
• Incorrect wiring or a wire shorting to ground.
• Lint filter is not clean.
• Drive motor winding shorting to ground.
• Restriction in exhaust.
Gas Models
• During ignition the dryer will draw X amps. With the
• Outside exhaust hood damper door stuck
burner ON, the dryer will draw X amps. If the dryer is
closed.
drawing amperages above this, then the house wiring,
• Exhaust too long, too many elbows, flex
fuse box or circuit breaker is suspected to be at fault.
ductwork installed.
• Igniter harness loose and shorted to base.
• Poor intake air available for the dryer.
• Incorrect wiring or wire shorted to ground.
• Incorrect tumbler speed. Tumbler belt slipping.
• Drive motor winding shorting to ground.
• Blower impeller bound; check for foreign
Will Not Dry
material in blower area.
Will not heat (motor runs):
• Customer overloading dryer.
• Open heating element.
• Check clothing labels for fabric content and
• Hi-Limit trips easily or is open.
cycle selected.
• Regulating thermostat trips easily or is open.
• Clothes too wet due to insufficient spin out by
washer.
• Membrane switch open.
• Check Thermistor.
2
16026117 Rev. 0
March 2005
©2005 Maytag Services
Troubleshooting
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
Will Not Shut Off
• Check Membrane Pad.
• Check Electronic Control Board.
• Short in sensor circuit.
Diagnostic Tests
The following table lists the various tests available while
in the Service Mode. Before advancing to the next test,
the current test running must be terminated.
Troubleshooting the electronic control circuit:
• Check for miswiring of the electrical connector at
the electronic control board.
Press the following keys to access:
Key Press
Special Test/Function
Display list of diagnostic
Wrinkle Prevent
codes.
Displays “d”
Noisy and/Or Vibration
• Thumping Check for loose tumbler baffle, rear
tumbler roller(s) worn or misaligned, out-ofround tumbler or high weld seam on tumbler.
• Ticking Check for loose wire harness or object
caught in blower wheel area.
• Scraping Check for front or rear bulkhead felt
seal out of position or worn tumbler front
bearings.
• Roaring Check for blower wheel rubbing on
blower housing or bad motor bearings.
• Popping or squealing sound. Check for a
sticky or frayed belt.
Temperature Key
Display software revision
number
Start or pause cycle running
but remain in diagnostic
mode. Display the number of
cycles ago the diagnostic
code occurred.
System Check Mode
While in Service Mode, pressing the
Time and Wrinkle Prevent keys for 3 seconds, will put
the dryer into the System Check mode and "in" will
display. The following table lists the various functions
based on the keys being pressed.
This mode provides Service Personnel the ability to
verify the operation of the dryer.
The Service Mode can be implemented at any time,
including the middle of a dry cycle. While in the Service
Mode, the Technician can start special diagnostic tests
such as a System Check Mode, LED Switch/Check,
Display Software version number and display
diagnostic/help code listings.
System Check Mode Table
Key Pressed:
Start/Pause rotary
selector dial
Rotate the Cycle Selector
Knob to Delicates
Enter Service Mode:
Dryer must be on before Service Mode can be entered.
Press Chime and Temperature Keys for 3 seconds, or
until 3 beeps are heard. The machine will now be in
Service Mode. Upon entry into Service Mode, the Sensor
Bar Touch Data is to be displayed.
Rotate the Cycle Selector
Knob to Sensor
Dry
Exit Service Mode
Press the OFF key to exit Service Mode or repeat the
Chime and Temperature sequence.
March 2005
To sequence thru the
diagnostic and help codes.
Start/Pause
Service Mode
©2005 Maytag Services
Then rotate the Cycle
Selector Knob
3
Function
Performed
Cycles the motor
on/off.
LED’s and 7
segment display
flash.
View current
cycle temperature
in Celsius.
Rotate the Cycle Selector
Knob to Wrinkle Control
Segment display
is “1” for sensor
bar short, “0” for
sensor bar open
Rotate the Cycle Selector
Knob to Time Dry
View current
cycle
temperature in
Fahrenheit.
16026117 Rev. 0
Troubleshooting
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
While a diagnostic code is displayed, if the Start/Pause
button in the center of the Rotary Cycle Selector is
pressed and held, the machine will display the number of
cycles ago the diagnostic code occurred. When the
Start/Pause button is released, the diagnostic code is
again displayed.
LED/Switch Check
While in Service Mode, pressing the Chime and Wrinkle
Prevent keys for 3 seconds, will start a LED/Switch Test.
To exit the test at any point, press the same keys again
for 3 seconds or press the OFF key to exit Service
Mode.
Clearing Diagnostic Codes
Perform the check by pressing the keys which toggle the
LED’s on and off.
To clear the diagnostic code list press the Sensor Dry
Level and Time keypads together for 3 seconds while
viewing the list. The cycle count for each diagnostic code
will be reset to 0, but not the machine cycle count.
All switch pads must be pressed within 5 minutes for this
test to pass. PA will be displayed for five (5) seconds
once all switch pads have been pressed and this test is
completed. Following 10 seconds of inactivity at any
point, the test will exit without any display. The Power
Off switch pad must be pressed twice within thirty (30)
seconds to cancel this test.
Switch
Action
Wrinkle Prevent
Chime
Adjust Time
Time
Temperature
Dryness Level
Selector Knob
Start Pause
Off
Press once
Press twice
Press once
Press four times
Press three times
Press four times
Rotate 1 position
Press once
Press once
Diagnostic Codes
Code Description
Dryer
1
Thermistor
Short Sensed
2
Action Taken
Check for:
- Clogged lint
screen.
- Restricted vent
system.
- Check Thermistor
resistance.
Check for:
Low ambient
temperature in
room (Below
The
Thermistor
resistance is
very high
°
°
-22 F/-30 C).
Outside vent
damper is stuck
open in
wintertime.
- Loose or open
wire terminals.
- Check Thermistor
resistance.
Check for:
- Loose or open
wire terminals in
Door Sense
circuit.
Check for:
- Loose
connections in
motor circuit.
- Run System
Check Mode and
check the motor
relay function.
- If relay functions,
disregard the
diagnostic code.
- If relay does not
function, replace
machine control
board.
-
Diagnostic Codes
The Diagnostic Codes are identified when the severity
level of the abnormality detected is higher and service
may be required.
When a problem with the dryer is detected a Diagnostic
Code is assigned, and can be displayed. The Control
Board will not log multiple same codes per cycle;
however, it will log as many Diagnostics as possible for
the machine to continue running.
Access Diagnostic Codes by entering the Service Mode
and pressing Wrinkle Prevent. A d will be displayed.
Rotate the Cycle Selector Knob in either direction to step
through the list of codes one code at a time. Once an
initial direction is selected by the user (either Clockwise
or Counterclockwise), subsequent movements of the
knob in the same direction will show older codes. If the
user changes direction and turns the knob in the
opposite direction, the more recent code will be
displayed.
16026117 Rev. 0
Thermistor
Open Sensed
Trigger
The
Thermistor
resistance is
very low.
4
3
Door Circuit
Failure
Invalid state
for more
than 256
milliseconds
4
Possible motor
transistor error
If either
motor
transistor is
seen open
or shorted
during
startup
March 2005
©2005 Maytag Services
Troubleshooting
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
Code
8
10
Description
Stuck Key
No Wet Clothes
Trigger
Action Taken
A key is
sensed to be
pressed
more than
75 seconds,
the key shall
be assumed
to be stuck.
Sensor bar
detects no
wet clothes
while a
Sensor Dry
Cycle
Run membrane pad
check and replace
console
w/membrane pad if
necessary.
Display Fault/Error Codes
Disp Description Trigger
Check for:
- Running dryer with
no wet clothes in
sensor dry cycle
Action Taken
tS
Dryer
Thermistor
Short Sensed
The Thermistor
resistance is very
low.
Check for:
- Clogged lint
screen.
- Restricted vent
system.
- Check Thermistor
resistance.
- Check for
diagnostic code 1
do
Door Open
Running the dryer
with door open
FE
Power source
frequency error
Invalid power
source frequency
dC
Door Circuit
Failure
Invalid state for
more than 256
milliseconds
hE
Heater Error
Invalid heating
temperature in
running the dryer
Check for:
- Close the door,
and run the dryer
- Loose or open
wire terminals in
Door Sense
circuit.
- Check for
diagnostic code 3
Check for:
- Not using regular
power source
frequency
- Invalid power
frequency sense
circuit
Check for:
- Loose or open
wire terminals in
Door Sense
circuit.
- Check for
diagnostic code 3
Check for:
- Restricted vent
system.
- Check Thermistor
resistance.
March 2005
©2005 Maytag Services
5
16026117 Rev. 0
Component Testing
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
Illustration
Component
Thermistor
Door Switch
Light
Belt Switch
Motor
TH1 Thermostat
Test Procedure
Unplug harness connector and test from
wire insertion side.
Pin #2 and Pin #6 of CN6
Results
10k ohms @ 77F NTC
Unplug connectors and test switch
terminals.
Door open terminals COM to NC/ 1 to 3
Door open terminals COM to NO/1 to 2
Door closed terminals COM to NC/ 1 to 3
Door closed terminals COM to NO/ 1 to 2
Unplug connectors and test switch
terminals.
Infinity
Less than 1 ohm
Infinity
Less than 1 ohm
Check across terminals
Unplug connectors and test switch
terminals.
80 to 100 ohms
Check across terminals switch closed
Check across terminals switch open
Unplug harness connector and test
motor circuits.
Less than 1 ohm
Infinity
Pin #4 and Pin #5 (Windings)
Pin #1 and Pin #2 (Centrifugal switch)
2 ohms
Open
Unplug connectors and test Thermostat
terminals.
85 C/185 F 25A
Check across terminals
Heater Element
Sensor Bars
Unplug connectors and test Heater
terminals
Unplug harness connector and test from
wire insertion side.
Pin #4 to Pin # 5 of CN6
Less than 1 ohm
10 ohms
Infinity (Dry load)
190 ohms ± 10% (Wet load)
Radiant Sensor
16026117 Rev. 0
Unplug connectors and test sensor
terminals.
6
Closed
March 2005
©2005 Maytag Services
Component Testing
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
Illustration
Component
TH2 Thermostatt
230F/110C
Test Procedure
Unplug connectors and test Thermostat
terminals.
Gas Valve
Unplug connectors and test valve
terminals.
Results
Less than 1 ohm
Check across terminals #1 and #3
(Booster Coil).
550 ohms
Check across terminals #1 and #2
(Holding Coil).
1350 ohms
Check across terminals #2 and #3 (Both
coils in series).
1900 ohms
Check across terminals #4 and #5
(Secondary Coil).
1300 ohms
Motor Contacts
Function
Start
Run
1M
2M
3M
5M
6M
= Contact closed
Centrifugal Switch (Motor)
Gas Valve
123
March 2005
©2005 Maytag Services
45
7
16026117 Rev. 0
Wiring Diagram
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power before servicing, unless
testing requires power.
16026117 Rev. 0
8
March 2005
©2005 Maytag Services