User manual MAYTAG MAH3000

Customer Service TM Washer Service Manual 16010061 Compiled From 16008373, 16010199, 16010886 11/03 SAFETY PRECAUTIONS This manual is to be used only by a Maytag Authorized Service Technician familiar with and knowledgeable of proper safety and servicing procedures and possessing high quality testing equipment associated with microwaves, gas, and electrical appliance repair. All individuals who attempt repairs by improper means or adjustment subject themselves and others to the risk of serious or fatal injury. USE ONLY GENUINE MAYTAG APPROVED FACTORY REPLACEMENT COMPONENTS. 16008373-01 © 1998 Maytag Corporation SAFETY PRECAUTIONS INTRODUCTION Each model will be covered separately in a section pertaining only to its control system and internal components. Because the basic structure for all washers is the same, they will be covered generally without regard to model. Model(s) covered in this manual: MAH3000 For additional information on material covered in this manual, including safety issues, contact: Maytag Appliances Sales Company 240 Edwards Street, S.E. Cleveland, TN 37311 Phone: 423.472.3333 FAX: 423.478.6722 16008373-01 © 1998 Maytag Corporation INTRODUCTION i CONTENTS I N T R O D U C T I O N ........................................................................................................................................................... i C O N T E N T S ....................................................................................................................................................................... i i SECTION 1. G E N E R A L I N F O R M A T I O N ...................................................................................................... 1 - 1 PRE-INSTALLATION REQUIREMENTS ............................................................................................................ 1 - 1 U N C R A T I N G ....................................................................................................................................................................... 1 - 1 I N S T A L L A T I O N.................................................................................................................................................................. 1 - 2 GROUNDING POLARITY CHECKS ...................................................................................................................... 1-4 S P E C I F I C A T I O N S ............................................................................................................................................................. 1-4 WASHER CONTROLS ................................................................................................................................................... 1 - 5 INPUT DEFINITIONS ..................................................................................................................................................... 1 - 6 OUTPUT DEFINITIONS ............................................................................................................................................... 1 - 8 CYCLE SEQUENCE DEFINITIONS ................................................................................................................... 1 - 1 0 M I S C E L L A N E O U S ....................................................................................................................................................... 1 - 1 1 Door Latch Switch Monitoring .................................................................................................................... 1 - 1 1 Door Lock/Spin Control ................................................................................................................................... 1 - 1 1 Redistribution ......................................................................................................................................................... 1 - 1 1 Push-To-Start Relay Operation .................................................................................................................... 1 - 1 2 CYCLE REVIEW ............................................................................................................................................................. 1 - 1 3 GENERAL COMPONENT EXPLODED VIEW ............................................................................................ 1 - 1 4 S E C T I O N 2 . E L E C T R I C A L C O M P O N E N T S & T E S T I N G .................................................................. 2 - 1 ELECTRICAL TEST EQUIPMENT ........................................................................................................................ 2 - 1 ELECTRICAL TESTS ..................................................................................................................................................... 2-2 Grounded Components ..................................................................................................................................... 2-2 Voltage Checks ......................................................................................................................................................... 2-2 Water Valve Test....................................................................................................................................................... 2-2 Wax Motor Check/Door Lock Mechanism ............................................................................................ 2-2 Timer & Console Switches ............................................................................................................................... 2-3 Timer Input Charts .................................................................................................................................................. 2-3 Machine Control....................................................................................................................................................... 2-5 DRIVE MOTOR ................................................................................................................................................................... 2-7 MOTOR CONTROL BOARD ...................................................................................................................................... 2-7 Motor & Motor Control Test ............................................................................................................................ 2-8 Motor Phase Test .................................................................................................................................................... 2-8 Motor Windings Check ....................................................................................................................................... 2-9 Tachometer Circuit Diagnostics ................................................................................................ .............2-10 UNBALANCE CONTROL SYSTEM .................................................................................................................. 2 - 1 1 Tub Displacement Switch ............................................................................................................................... 2 - 1 2 Strut Displacement Switch ............................................................................................................................ 2 - 1 2 Inertial Unbalance Switch ............................................................................................................................... 2 - 1 3 Cabinet Vibration Sensor ............................................................................................................................... 2 - 1 3 Cabinet Vibration Absorber ......................................................................................................................... 2 - 1 3 16008373-01 © 1998 Maytag Corporation CONTENTS ii SECTION 3. T R O U B L E S H O O T I N G ................................................................................................................ 3 - 1 DIAGNOSTIC FLOW CHARTS....................................................................................................3-4 Fills and Will Not Tumble ................................................................................................................................... 3-4 Washer Overfills ....................................................................................................................................................... 3-5 Washer Will Not Spin ........................................................................................................................................... 3-6 Machine Stalls During Spin ............................................................................................................................... 3-8 Maximum Spin Speed Is Not Reached ................................................................................................... 3-9 Wash Cycle Takes Longer Than Normal .............................................................................................. 3 - 1 0 Suds Coming Out Of Door ............................................................................................................................. 3 - 1 0 Washer Will Not Start ........................................................................................................................................ 3 - 1 1 Motor Phase Test ................................................................................................................................................. 3 - 1 2 TIMER TEMPLATE OVERLAY ............................................................................................................................. 3 - 1 3 MISCELLANEOUS INFORMATION .................................................................................................................. 3-14 S E C T I O N 4 . C O N S O L E ............................................................................................................................................ 4 - 1 R E M O V A L ............................................................................................................................................................................. 4-1 VERTICAL SWITCHES.................................................................................................................................................. 4-2 HORIZONTAL SWITCHES .......................................................................................................................................... 4-2 TIMER REMOVAL/REPLACEMENT.................................................................................................................... 4-3 S E C T I O N 5 . C A B I N E T A S S E M B L Y ................................................................................................................. 5 - 1 DOOR ASSEMBLY & HINGES ................................................................................................................................. 5 - 1 Cabinet Vibration Absorber ............................................................................................................................ 5-2 Door Latch Hoop ..................................................................................................................................................... 5-2 FRONT PANEL ................................................................................................................................................................... 5-2 TOP COVER ......................................................................................................................................................................... 5-3 DOOR LOCK MECHANISM ....................................................................................................................................... 5-3 FRONT SHROUD ASSEMBLY ................................................................................................................................. 5-4 CABINET ASSEMBLY W/REAR ACCESS PANEL...................................................................................... 5-5 S E C T I O N 6 . W A T E R C A R R Y I N G C O M P O N E N T S ................................................................................ 6 - 1 WATER VALVE................................................................................................................................................................... 6 - 1 WATER LEVEL PRESSURE SWITCH.................................................................................................................. 6-2 AIR DOME HOSE .............................................................................................................................................................. 6-2 DISPENSER ASSEMBLY ............................................................................................................................................. 6-3 FRONT WATER FLUME INJECTOR..................................................................................................................... 6-4 PUMP ASSEMBLY .......................................................................................................................................................... 6-4 Pump Accessory ..................................................................................................................................................... 6-5 DRAIN HOSE ....................................................................................................................................................................... 6-6 SECTION 7. OUTER TUB & SPINNER ASSEMBLY ............................................................................ 7 - 1 B A F F L E S ................................................................................................................................................................................ 7 - 1 DOOR BOOT ........................................................................................................................................................................ 7 - 1 OUTER TUB COVER ...................................................................................................................................................... 7-2 SPIN BASKET ASSEMBLY W/BALANCE RING .......................................................................................... 7-3 DRIVE PULLEY .................................................................................................................................................................. 7-4 SPINNER TUB SUPPORT ........................................................................................................................................... 7-5 iii 16008373-01 ©1997 Maytag Corporation CONTENTS SEAL SYSTEM .................................................................................................................................................................. 7-6 OUTER TUB ASSEMBLY ............................................................................................................................................ 7-7 B E A R I N G S ............................................................................................................................................................................ 7-7 COUNTER WEIGHTS .................................................................................................................................................... 7-7 STRUT ASSEMBLY ........................................................................................................................................................ 7-8 Strut Displacement Switch ............................................................................................................................... 7-8 INERTIAL UNBALANCE SWITCH......................................................................................................................... 7-8 TUB DISPLACEMENT SWITCH ............................................................................................................................. 7-9 SECTION 8. MOTOR DRIVE SYSTEM ........................................................................................................ 8 - 1 DRIVE BELT ......................................................................................................................................................................... 8 - 1 DRIVE MOTOR ................................................................................................................................................................... 8 - 1 MACHINE CONTROL .................................................................................................................................................... 8-2 MOTOR CONTROL ......................................................................................................................................................... 8-3 SECTION 9. E L E C T R I C A L S C H E M A T I C S .................................................................................................. 9 - 1 Schematic Prior to Series 17 .......................................................................................................................... 9 - 1 Timer Chart Prior to Series 17 ....................................................................................................................... 9-2 Schematic Series 17 .............................................................................................................................................. 9-3 Timer Chart Series 17 .......................................................................................................................................... 9-4 Schematic Series 18 .............................................................................................................................................. 9-5 Timer Chart Series 18 .......................................................................................................................................... 9-6 Schematic Series 19 .............................................................................................................................................. 9-7 16008373-01 © 1998 Maytag Corporation CONTENTS iv SECTION 1. GENERAL INFORMATION PRE-INSTALLATION REQUIREMENTS NOTE: Proper installation is the responsibility of the purchaser. cause an extended fill time. Refer to the troubleshooting section for more information regarding a solution for slow fill situations. · Best performance is obtained with the washer installed on a solid floor. Wood floor constructions may need to be reinforced to minimize vibration from unbalanced load situations. Carpets and soft tile surfaces are also contributing factors to vibration and/or movement during the spin cycle. Never install washer on a platform or weak support structure. Checkpoints for proper installation: · Properly grounded electrical outlet is required. Use 15 amp fuse or compatible circuit breaker for electrical service. Standpipe Drain System must accept 1½" O.D. drain hose. Standpipe height of 36" is recommended. · NOTE: If drain standpipe is in excess of 5 feet above floor level, install pump accessory kit, part number 22002136. · This unit is not equipped with a siphon break, and the drain hose must be elevated to a minimum height of 24". A 36" high standpipe is recommended. For all installations the drain hose must be supported by the drain hose strap on the back of the washer. Hot and Cold water faucets must be within four (4) feet of the back of the washer. This allows quick access for immediate water shut off. Water heater should be set to deliver a minimum of 120ºF (49º C) hot water to the washer. 3. · Do not store or operate washer in temperatures below freezing. This can cause damage to the pump, hoses and other components. Water pressure of 20 - 120 P.S.I. is required to fill the washer in the appropriate time frame. Pressures of less than 20 P.S.I. may UNCRATING INSTRUCTIONS NOTE: The following steps must be performed in the correct order to ease uncrating. 1. Remove the carton by cutting only in marked areas of the carton. CAUTION: Hoses are connected to the washer. Carefully remove any packaging materials from the outside of the washer. IMPORTANT: DO NOT cut the red straps securing the power cord and inlet hoses at this time. They will be removed later during installation. Remove the accessory package from inside the tub. Remove the crate bottom from the washer by removing crate bottom wire clips. · 2. · 4. · 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-1 INSTALLATION 1. Two separate red shipping straps are used to secure the machine for shipping purposes and to secure the power cord with the water inlet hoses. Remove the straps in the following sequence: A. Locate the metal buckles securing the red straps which extend through slots in the rear wall of the cabinet. The buckles are positioned in the center of the red straps. Carefully cut the red straps, and remove the metal buckles. NOTE: Cut the straps as close to the buckles as possible. Discard the buckles. 3. Figure 1-2 Locate the two (2) ½" hex head shipping bolts extending up through the bottom of the base (Figure 1-4). The shipping bolts are near the center of the base toward the front of the washer. Remove both bolts, freeing the tub and suspension. Do not be alarmed should the tub assembly shift when the last bolt is removed. Some shifting of the tub is normal. Figure 1-1 B. Grasp each loose strap individually and pull the strap to remove it from the cabinet. Discard the strap (Figure 1-2). 2. Tip washer slightly forward. Loosen rear leveling leg lock nuts. Tip washer back slightly to loosen front leveling leg lock nuts (Figure 1-3). Figure 1-3 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-2 Turn on the water and check for leaks (Figure 1-5). Note the H and C designations on the water valve bracket for the Hot and Cold hoses. Figure 1-4 Figure 1-5 4. Slide the washer into position and check the levelness and stability of the washer. If necessary, slide the washer out of position to either raise or lower the leveling leg as required to level and stabilize the washer securely on all four legs. Slide the washer back into position to confirm levelness to the floor. When the washer is level, tighten the locking nuts up against the base of the washer. This will secure the leveling legs in place. Install the rubber feet, found in the installation package, on all four (4) legs (Figure 1-3). Pull the drain hose vertically to the drain strap . Then route the drain hose through the drain hose strap on the back of the washer and snap into the plastic hook of the strap. Install gooseneck end of drain hose into drain standpipe. Be sure the connection is not airtight between the drain hose and standpipe. Standpipe must be at least 24" high. 36" height is recommended. Connect inlet hoses to water supply using screen washers (found in the installation package) at faucet connections, with the domed screen facing the faucet. Attach hoses to the faucets and the water valve. NOTE: Accessory inlet hoses are available in various lengths, up to 10 feet. GROUNDING POLARITY CHECKS The receptacle used for all Maytag products operating on 120 Volts AC must be properly grounded and polarized. The power cord should be equipped with a three (3) PRONG POLARIZED GROUNDING PLUG FOR PROTECTION AGAINST SHOCK HAZARD and should be plugged directly into a properly grounded and polarized receptacle. CAUTION: Do not cut or remove the grounding prong from this plug. It is the responsibility of the person installing the appliance to ensure it is adequately grounded and polarized at the point of installation. Local conditions and requirements should be taken into consideration. In cases where only a two (2) prong receptacle is available, it is the personal responsibility of the customer to have it replaced with a properly grounded and polarized three (3) prong receptacle (Figure 1-6). 5. 6. 7. 8. 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-3 Plug power cord into a properly grounded 120 volt AC-approved electrical service. This must be protected by a dedicated 15 amp fuse or circuit breaker. All grounding and wiring should be performed in accordance with national and local codes. USE OF ADAPTERS IS NOT RECOMMENDED. Figure 1-6 SPECIFICATIONS CAPACITY ELECTRICAL 3.1 Cubic Feet 120 volts, 60 Hz; Requir es 15 amp circuit br eaker or fused electrical supply . Power cord must be connected to a properly grounded and polarized outlet. Sw itched Reluctance M otor contr olled by a micropr ocessor motor contr ol board. Motor pulley ratio (motor to spinner RPM ) 14 to 1. Motor Input: During Wash Tumble During Rinse Tum ble Top Spin (Wattage readings taken with no clothes in Wash Tumble Rinse Tum ble High Speed Spin - 150 Watts - 175 Watts - 800 Watts spinner.) M OTOR POWER U SAGE TUMBLER SPEED 47-51 RPM 47-51 RPM 800 RPM (± 50 RPM based upon optim um spin performance.) WATER U SAGE Water pressure should be 20-120 p.s.i. (1.06-8.44 kg/cm ) at inlet hose connection. Total w ater usage is approximately 25 gallons; varies w ith clothes load. Water fill in the spin basket w ith no clothes, m easured near the rear seam of the spin basket. WASH LEVEL 3-4 inches RINSE LEVEL 4-5 inches Four-foot inlet hoses w ith inlet washers and attaches to water valv e. Dr ain hose attaches to pump and w ill accomm odate 36" dr ain stand pipe. Cabinet dimensions: 27" (68.58cm) W x 27 ½" (69.85cm) D x 36" (91.44cm )H . Uncar toned Crated 190lb. (86kg.) Approx . 200lb. (91kg). Approx . 7in. lbs. 30in. lbs 90in. lbs 25in. lbs 18.5in. lbs 15+ in. lbs 18in. lbs 7in. lbs (± (± (± (± (± 3in.lbs) 3in. lbs) 10in. lbs) 3in. lbs) 3in. lbs) HOSE LEN GTHS DIMENSIONS WEIGHT (Approx.) SCREW & BOLT TORQUES Bolt, Counter Weight Bolt, Spin Pulley Bolt, Belt Adjuster Screw , Fr ont Baffle Screw , Rear Baffle Clamp, Hoses Nuts, Spinner Support Nuts, Suspension Struts (± 3in. lbs) (± 3in. lbs) 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-4 WASHER CONTROLS The control system in the Neptune horizontal axis washer generally consists of a timer and microprocessor-based machine control. These receive input signals and send output signals to other equipment in the washer, including the motor and motor control, user input switches, user indicator lights, the door latch and lock assembly, water valves, drain pump, unbalance switches, dispenser actuator wax motors, a pressure switch, and a tub light. The machine control has direct control of these items: Motor speed and direction, through signals to the motor control. Door lock wax motor. Hot and cold water valves, with an input signal from the timer and pressure switch. Timer motor. On Light. In general, the timer dial is rotated to a desired setting, selects the cycles options using the option switches, and starts the washer. The machine control reads the inputs from the timer, option switches and pressure switch then send output signals to the motor control and other components based upon those inputs. When the machine control has completed its set of instructions for the specific timer setting, it energizes the timer motor output to advance the timer to the next increment, reads a new set of input signals from the timer, and acts upon them. This continues until the cycle is complete. (See Figure 1-7 & 1-8 for a generic representation of the Neptune washer control system.) Prior To Series 17 Figure 1-7 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-5 Series 17 & Later Figure 1-8 INPUT DEFINITIONS DOOR LOCK SWITCH INPUT When input is present, this is indication the washer door is locked. The machine controller will not command the spinner to spin faster than 50 rpm when the input is not present prior to spin. END-OF-CYCLE SIGNAL INPUT The End-of-Cycle Signal Input is energized through a user input switch on the control panel. When this is energized and the cycle has finished, the machine control will sound the End-of-Cycle signal (See End-Of-Cycle Signal Output). FABRIC SELECTION INPUTS The Fabric Selection Inputs are energized through a user input switch on the control panel. The machine control reads these inputs to determine which cycles should be run when the washer is started. MAX EXTRACT INPUT The Max Extract Input is energized through a user input switch on the control panel. When input is energized, the machine control will modify the final spin profile to the max extract profile. 16008373-01 NOTE: If the user selects the Hand Washables fabric selection, all spins will follow the Max Extract profile regardless of whether the user selects the Max Extract option. OUT-OF-BALANCE INPUT The Out-of-Balance Input Signal is provided by three normally-closed switches wired in sequence. If any of these switches opens due to an out-of-balance condition, the signal will be momentarily lost (See Unbalance Control System). PRESSURE SWITCH INPUT The input signal from the Pressure Switch serves two purposes. It supplies power for the water valves and provides an indication to the machine control as to whether the commanded water level has been reached. When the timer advances into a cycle sequence that calls for water, power is supplied through the timer to either the wash or rinse level contacts on the pressure switch. When the water level in the tub is below the full level for that setting, the pressure switch circuit is closed, supplying power for the water valves to the machine control. When the water level switch is satisfied, the pressure switch circuit is opened and power for the water valves is no longer passed to the machine control. The SECTION 1. GENERAL INFORMATION © 1998 Maytag Corporation 1-6 machine control interprets this loss of power as an indication that the water level has reached the full level. When the washer is at the "full" level and the timer is set in a Prewash Tumble, Main Wash Tumble, Light Wash Tumble, or Rinse Tumble increment, the machine control will begin the sequence timing defined for each cycle and fabric selection setting (See Cycle Sequence Definitions). During the drain and spin increments after the main wash, first rinse, second rinse, and extra rinse increments, the wash side circuit in the pressure switch is closed. When the water level drains below the wash full level, the circuit will close and energize the pressure switch input. The machine control interprets this signal (not to energize the water valve outputs) to measure how quickly the washer is draining. If the machine control commands a spin speed above 51 rpm before the pressure switch input is energized, it will drop the speed to 0 rpm and hold there until the pressure switch input is energized. An additional delay equal to the length of time elapsed will occur before the pressure switch input is energized. If four minutes elapse without the pressure switch input being energized, the machine control will energize the timer motor output to advance the timer into the next increment and continue with the cycle. START/STOP INPUT The start/stop input is energized by the momentary Push-to-Start/Stop Switch. If this input is energized when a cycle is in progress, the machine control will disengage the line relay, both water valve output signals, the door lock wax motor signal, the timer motor output signal, and the on-light output signal. If this input is energized when a cycle is not in progress, the machine control will energize the line relay and begin the cycle sequence as defined by the timer and user input switches (See Push-To-Start/Line Relay Operation). 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 five seconds, it will disengage the line relay to stop the washer. This generally indicates a locked rotor or a malfunction in the motor control. If the machine control senses a tach input signal when it is not commanding the motor to run, it will disengage the line relay to stop the washer. 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 disengage the line relay to stop the washer. TEMPERATURE SENSOR INPUT A thermistor is located in the water valve to monitor the blended incoming water temperature. The machine control uses this input signal to regulate the water temperature with the warm or cold wash or warm rinse temperature selections (See Water Valve Outputs). TIMER INPUTS The Timer Input signals are energized through the cams in the timer. The timer operates with a 30 second drive cycle and a 5.8 second advance time (See Timer Input Charts). WATER TEMPERATURE INPUTS The Water Temperature inputs are two separate signals defined by a user input switch on the control panel. The machine control interprets these signals to determine what the water temperature should be for each fill (See Water Valve Outputs). 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-7 OUTPUT DEFINITIONS DOOR LOCKED LIGHT OUTPUT NOTE: This section applies only to washers between Series 10 and 16. The "Door Locked" lights on washers from Series 17 and after are controlled by a "Door Locked" light switch. The Door Locked Light Output signal powers a 1/3 watt neon indicator lamp on the control panel. This output is first energized when the Door Lock Wax Motor Output is energized. At the end of the cycle, it remains energized for 50 seconds after the Door Lock Switch Input shuts down. This delay allows the wax motor to fully retract and unlock the door. NOTE: The washer will continue to tumble at the end of cycle until this 50 second delay is elapsed. DOOR LOCK WAX MOTOR OUTPUT The Door Lock Wax Motor Output signal powers a wax motor in the door lock assembly. The wax motor extends to drive the door lock system for the washer. If the washer is started with the timer set in a Prewash Tumble, Main Wash Tumble, or Light Wash Tumble increment, the machine control will wait for three minutes before energizing the Door Lock Wax Motor Output. This delay is not affected by water level. This output remains energized until the end of the cycle. If the washer is started with the timer set in a Prewash Drain, Bleach Dispense, Spin1, Rinse Tumble, Spin2, or Spin3 increment, the machine control will energize this output immediately. The machine control will continuously energize the Door Lock Wax Motor Output during the final (Spin 3) sequence until 30 seconds before the washer begins to coast from the final speed. 16008373-01 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-ofcycle signal sounds when a wash cycle is finished and the End-Of-Cycle Input is energized. The end-of-cycle signal sounds as six pulses in a 0.35 seconds on, 0.15 seconds off pattern (See Timer Input Charts). ON LIGHT OUTPUT NOTE: This section applies only to washers from Series 17 and after. The "Door Locked" lights on washers between Series 10 and 16 are controlled by a cam on the timer. The Door Locked Light Output signal powers a 1/3 watt neon indicator lamp on the control panel. This output is energized when the washer is operating in a wash or spin cycle. Note that the "On" light is not illuminated when the timer is in a delay increment. TIMER MOTOR OUTPUT The machine control energizes the Timer Motor Output to allow for variable-length timer increments. If the washer is started with the timer set in a Prewash Tumble, Main Wash Tumble, Light Wash Tumble, or Rinse Tumble increment, the machine control will not begin the cycle sequence timing until the water level reaches the appropriate level. The Timer Motor Output is disengaged during this time. The machine control will stop the washer by disengaging the line relay if the following occur: 1) The machine control energizes the timer motor until it senses a timer change. 2) The timer motor remains energized for five minutes while the timer inputs change (See Timer Input Charts). © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-8 The machine control counts the number of rinses during a normal wash cycle. In the first and second Rinse Tumble increments, the machine control will energize the Timer Motor Output as soon as the Pressure Switch Input is no longer energized, indicating that the water has reached the full level. In the third and fourth (if Extra Rinse is selected) Rinse Tumble increments, the machine control will energize the Timer Motor Output 30 seconds after the Pressure Switch Input is no longer asserted. The machine control will energize the Timer Motor Output when the timer is set into a Spin1, Spin2, or Spin3 increment 30 seconds before the end of the spin. It will remain energized until the timer inputs change. TORQUE OUTPUT The machine control commands motor speed and direction through the Torque Output from the machine control to the motor control. This output is a pulse width modulated (PWM) signal (See Section 2: Machine Control). Vcc REFERENCE VOLTAGE OUTPUT The Vcc Outputs are a reference voltage for many of the signal outputs. On the machine control, the Vcc outputs are 24 VDC referenced to the 120 VAC neutral line. WATER VALVE OUTPUTS The machine control determines whether the hot or cold Water Valve Outputs should be energized during each timer increment, but it only gates the power to the water valves, it does not directly provide that power. When the timer is in an increment calling for water, power passes from the timer to the wash or rinse level circuit in the pressure switch. When the water level is below the full level, the pressure switch circuit is closed and the power passes to the machine control. The machine control gates the power to the hot and cold Water Valve Outputs. When the pressure switch senses that the full level is reached, the circuit opens and de-energizes the Pressure Switch Input on the machine control, which de-energizes the Water Valve Outputs. The machine control will read the Water Temperature Sensor Input to determine the blended water temperature passing through the water valve. In a warm wash fill, the machine control will first energize both the hot and cold Water Valve Outputs for five seconds then de-energize the cold Water Valve Output and monitor the water temperature. When the Water Temperature Sensor Input passes the warm threshold (approx. 20 K Ohms), the machine control will re-energize the cold output for the remainder of the fill. In a cold wash fill, the machine control will first energize only the cold Water Valve Output for five seconds. It then energizes the hot Water Valve Output and monitors the Water Temperature Sensor Input until it passes the cold threshold (approx. 44 K Ohms), when it de-energizes the Hot Water Valve Output for the remainder of the fill. If the user selects a warm rinse temperature, the machine control will count the rinses and allow a warm rinse fill only on the third and fourth (if the user also selects the Extra Rinse option) rinses. The first two rinses will be cold only. The machine control does not regulate water temperature during the rinses. NOTE: If the user chooses the Easy Care/ Perm Press fabric selection, all rinse fills will be cold regardless of whether the user also selected the warm rinse temperature. 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-9 CYCLE SEQUENCE DEFINITIONS NOTE: Refer to Section 2: Timer Input Charts for information on the timing of each cycle sequence. BLEACH DISPENSE In a Bleach Dispense increment, the machine control will follow the same tumble pattern and speed as in a Main Wash Tumble increment. D E L AY During a Delay increment, the door Lock Wax Motor Output, Door Locked Light Output (Series 17 and later only), Motor Torque Output, "On" light (Series 10 to 16 only), and Water Valve Outputs are de-energized. Note that the Delay indicator is energized through a cam on the timer. EXTRA RINSE When the user selects the Extra Rinse option, the spin increment following the third rinse will follow the Spin2 cycle sequence. The Timer Motor Output will be energized 60 seconds prior to the end of the spin cycle sequence and will remain energized to advance the timer through the "Off" increment into the Rinse Tumble increment. If the Extra Rinse option is not selected, this spin will follow the Spin3 cycle sequence and the Timer Motor Output will be energized 30 seconds prior to the end of the final spin. IDLE The Idle increment follows the final spin increment in each cycle. If the Door Lock Switch Input is energized when the timer advances into the Idle increment at the end of the cycle, the machine control will tumble the washer until 50 seconds after the Door Lock Switch input is no longer energized. This allows time for the Door Lock Wax Motor to fully retract. At this time, the Door Lock Light Output (washers between Series 10 and 16 only) or the "On" Light Output (Series 17 and later 16008373-01 washers only) will de-energize and the Endof-Cycle Signal will sound if the user had selected the End-of-Cycle Signal option. LIGHT WASH TUMBLE, MAIN WASH TUMBLE, and RINSE TUMBLE The machine control will tumble the washer at the pattern and speed defined by the Fabric Selection Inputs (See Cycle Review). Each tumble will start only after the previous tumble has completely stopped. The machine control will reverse the tumble direction after each pause. The machine control will continue to tumble the washer until the timer inputs change. In a Light Wash Tumble or Main Wash Tumble increment, the machine control will de-energize the line relay if the washer continues to tumble for 29 minutes. This would only occur if the timer were to stall (See Section 1: Timer Motor Output and Section 2: Timer Input Chart). PREWASH DRAIN During a prewash drain increment, the washer will tumble at the same speed and in the same pattern as in the Prewash Tumble increment for the fabric selection. The Door Lock Wax Motor Output will be energized during this increment (See Prewash Tumble). PREWASH TUMBLE When the timer is set into a Prewash Tumble increment, the machine control will tumble at 51 rpm in the following tumble pattern: Cycle Tumble-Pause Pattern Cotton/Sturdy 6 sec. - 24 sec. Easy Care/Perm Press 6 sec. - 24 sec. Delicates 6 sec. - 24 sec. Hand Washables 3 sec. - 27 sec. © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-10 In a Prewash Tumble increment, the machine control will de-energize the line relay if the washer continues to tumble for 15 minutes. This would only occur if the timer were to stall (See Section 1: Timer Motor Output and Section 2: Timer Input Chart). control will energize the timer motor output until the timer inputs change so the washer can proceed with the cycle. At the end of spin sequence, if the door lock switch input is de-energized before the washer drops below 91 rpm, a hardware circuit on the machine control will interrupt the torque output signal, which forces the motor control to 0 rpm, and energize the door lock wax motor circuit to lock the door. This hardware circuit will keep the door lock wax motor circuit energized until the door lock switch input signal is energized. MISCELLANEOUS Door Latch Switch Monitoring At the end of a cycle, when the timer advances into the Idle increment, the machine control will keep the line relay energized until it loses power when the door latch switch opens. This guards against the switch contacts welding closed. In this condition, the machine control will limit what additional cycles can be run before the door is opened as follows: Washers between Series 10 and 16 The machine control will allow the washer to restart only if the user sets the timer into a Rinse Tumble or Spin3 increment. Washers from Series 17 and Later The machine control will allow the washer to restart in any setting. After that cycle completes, the user must open the door before the machine control will allow a third cycle to start. Redistribution The machine control commands a distribution profile speed ramp from 0 rpm to 85 rpm at the beginning of each high speed (above 100 rpm) spin. When the washer reaches 85 rpm, the machine control monitors the Tach Input to determine if the speed varies through one revolution of the spinner basket. If it senses a high enough variation in speed (suggesting an out-of-balance condition in the clothing load), it will drop the spinner speed to 0 rpm and force a short reverse tumble to redistribute the clothing load before resuming the spin. If any of the out-of-balance switches trip and open the out-of-balance input circuit at a speed below 500 rpm, the machine control will also drop the speed to 0 rpm and force the reverse tumble to redistribute the clothing load. Door Lock/Spin Control When the machine control begins a spin increment, it will not command spin speed above 51 rpm unless the door lock switch input is energized. At the start of a spin increment, the machine control will drop the speed to 0 rpm then tumble until the switch is energized. At that point, it will restart the spin sequence. If the door lock switch is not energized after 2 minutes of tumbling, the machine 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-11 The following rules determine the maximum number of redistribution attempts that will be allowed in each spin step before the machine control skips the step and continues with the spin profile (See Section 2: Unbalance Control System). STOPPING THE WASHER 1. With the washer running, power is supplied to the machine control and washer from gray wire no. 26 through the line relay. 2. When the user presses the push-to-start button, a signal is sent to the machine control through red wire no. 28 telling the washer to shut down. 3. The machine control opens the internal logic switch which de-energizes the line relay. 4. When the user releases the push-to-start button, power is removed from the machine control and washer (Black wire no. 27). Push-To-Start Relay Operation STARTING THE WASHER 1. 2. 3. 4. 5. With the door closed, press the push-to start switch. The red no. 28 wire sends a signal to the machine control to start running. 120 VAC is supplied to the machine control board through black wire no. 27. The machine control closes an internal switch to energize the line relay. When the push-to-start button is released, power remains supplied to the machine control and the washer from gray wire no. 26 through the line relay. MACHINE CONTROL BOARD INTERNAL LOGIC SWITCH LINE RELAY NO C OM 120 VAC POWER FROM MACHINE CONTROL BOARD 120 VAC LINE (W hen door is closed) GY 26 BK 27 120 VAC Line To Timer & Motor Control Board RD 28 PUSH TO START SWITCH Figure 1-8 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-12 CYCLE REVIEW Main Wash Time/Total Cycle Time - Minutes (See Notes). N on- M ax Ex t ra c t H e a v y W a sh N o r m a l W a sh Lig h t/ Q u ic k W as h Fi n a l S p i n (R PM / M i n ) C ot t on/ S t urdy 2 3 .0 /4 9 . 0 1 7 .0 /4 3 . 0 1 1 .0 /3 7 . 0 80 0/3.5 E a sy C a r e / Pe rm Press 2 0 .0 /4 5 . 5 1 4 .0 /3 9 . 5 8 . 0 / 3 3 .5 60 0/ 3. 0 D e lic a t e s 20 /46.5 1 4 .0 /4 0 . 5 7 . 0 / 3 4 .5 50 0/4.5 H a nd W a sh a b l e s N o t A p p lic ab le N o t A p p lic ab le N o t A p p lic ab le N o t A p p lic ab le M a x Ex t r a c t C y c le s H e a v y W a sh N o r m a l W a sh Lig h t/ Q u ic k W as h Fi n a l S p i n (R PM / M i n ) C ot t on/ S t urdy 2 3 .0 /4 6 . 0 1 7 .0 /4 0 . 0 1 1 .0 /3 4 . 0 80 0/4.0 E a sy C a r e / Pe rm Press 2 0 .0 /4 1 . 5 1 4 .0 /3 5 . 5 8 . 0 / 2 9 .5 60 0/ 3. 5 D e lic a t e s 2 0 .0 /4 2 . 0 1 4 .0 /3 6 . 0 8 .0 /3 0 .0 50 0/5.0 H a nd W a sh a b l e s 2 0 .0 /4 3 . 0 1 4 .0 /3 7 . 0 8 .0 /3 1 .0 50 0/5.0 Notes: 1. The main wash times listed include 2 minutes of bleach fill and tumble time. 2. The total cycle times are approximate and will vary based on water fill times, due to types of clothing loads, available water pressure and the time for the door lock system to retract at the end of the cycle. The main wash time is affected significantly if the machine control detects an excessive amount of suds. The washer will go into a suds reduction routine, consisting of a series of additional rinse and partial drain cycles to reduce the suds present (See Troubleshooting & Diagnosis - Clothes Wet at End of Spin). 3. Tumble Pattern - Number of seconds tumbling/Number of seconds of pause between tumbles. Cot t on/ Sturdy 7/3 Easy Care/ Perm Press 5/3 Delicat es 6/24 Hand W ashab les 3/27 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-13 GENERAL COMPONENT EXPLODED VIEW 16008373-01 © 1998 Maytag Corporation SECTION 1. GENERAL INFORMATION 1-14 SECTION 2. ELECTRICAL ELECTRICAL COMPONENTS & TESTING EQUIPMENT often require the use of electrical testing equipment such as: TEST The equipment required to service Maytag products depends largely upon the conditions you encounter. Locating a malfunction will Description Analog Test Meter Digital Test Meter Clamp-On Ammeter Part Number 20000005 20001001 20000002 20000081 AC Voltage Sensor Analog Test Meter can be used to check for open or closed circuits, measure resistance, AC and DC volts, and temperature. Clamp-On Ammeter can be used to detect shorts. Overloads on the circuit breaker or fuse can be traced to either the washer or circuit breaker by checking the washer current draw. Digital Test Meter can be used to check for open or closed circuits, measure resistance, AC and DC volts, and temperature. AC Voltage Sensor can be used to alert you if AC voltage is present so proper safety precautions can be observed. The tip of the sensor will glow bright red if voltage is between 110-600 volts AC. 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-1 ELECTRICAL TESTS Warning - Always shut off electrical power to the unit before beginning any service repair procedures. Water Valve Test Check the water valve for electrical continuity. This check should be made with the electrical supply disconnected from the washer. Remove the wire harness from the water valve terminals and place the ohm meter probes on the terminals of the water valve. The water valve solenoid coil should have a resistance between 500-1000 ohms. If no ohms are shown on the display of the electrical test meter, the solenoid coil has an open winding and the valve should be replaced. The thermistor in the water valve changes in resistance in direct relationship to water temperatures. To monitor the performance of the thermistor, run a partial hot water fill and check the ohm resistance of the thermistor circuit. Then, run a cold water fill and measure the resistance again. There should be a notable difference in the resistance readings. To check the ohm resistance, pull the P2 wire harness connector off the machine control and locate the P2(5) and P2(6) leads in the connector (Figure 2-3). Grounded Components When performing service diagnostics, replacements and repairs, always check to determine whether all ground wires linking panel and components are reattached if removed. Voltage Checks Generally, these checks will consist of taking readings at the wall receptacle to determine the availability of voltage to the product. Voltage checks on individual components of a product are not recommended due to the possibility of electrical shock. Component part testing is best accomplished through continuity checks with an Appliance Test Meter (See Electrical Test Equipment). NOTE: Use of the meter on voltage higher than the indicated range may cause permanent damage to the meter. To prevent damage, first select the highest range and then lower the range for readings which fall within the lower scale. Set up meter for use as follows: 1. 2. 3. 4. Turn selector knob to desired meter function and appropriate range. Plug black lead into socket marked black (-). Plug red lead into socket marked red (+). Place test leads into receptacle to determine voltage available. Wax Motor Check - Door Lock Mechanism Check the wax motor for proper resistance. This check should be made with the electrical supply disconnected from the washer. Remove the wire harness from the wax motor terminals and place the ohm meter probes on the terminals of the wax motor. The wax motor should have a resistance of approximately 1900 ohms at room temperature. To check wax motors through console, see section: Machine Control page 2-5. 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-2 Timer & Console Switches The timer is located in the control console on the back. It is composed of a series of switches driven by an electric timer motor. The timer motor rotates a pinion gear which then rotates internal cams. As the cams rotate, they lift and drop various switch contacts which ride on the cam. The internal switches provide cycle sequence or step inputs to the machine control to control the pump, dispenser wax motors, delay light, ON light and timer motor. The timer wire harness connector can be pulled and the individual contacts for the various circuits can be checked with an ohm meter. As illustrated, timer contact for the drain pump is 14T (Figure 2-1). T C B Figure 2-2 motor windings. The following chart can be used for checking other components via the timer wire harness connector. Description Pump Motor Bleach Wax Motor Softener Wax Motor Timer Motor Connector 14T 2B 2T 10T Connector 10B 10B 10B 10B Ohms 18 950-1100 950-1100 5000 Figure 2-1 You can identify the wire for the drain circuit (Figure 2-2) by tracing down the side of the connector to contact 14, and across to align with column T. Contact 8B in the connector is a direct contact to the neutral leg of the timer. When an ohm meter probe is placed into the 14T connection and the other probe is placed into 8B, an ohm reading of the complete drain circuit can be performed. The drain circuit should have a resistance of approximately 18 ohms. This is the resistance reading of the pump Timer Input Charts As stated previously, the machine control board receives inputs from the timer monitor where the timer is in the cycle. The machine control board accomplishes this by routing four circuits through the timer. Two of the circuits (1A & 1B) are supplied with 120 VAC and the other two circuits (2A & 2B) are 24 VDC. The voltages for the four circuits is shown on the timer chart of the electrical schematic enclosed in the washer console. 16008373-01 SECTION 2. ELECTRICAL COMPONENTS & TESTING © 1998 Maytag Corporation 2-3 Software in the machine control board specifically monitors the timer input circuits to determine where the timer is in all the wash cycles and will rapidly advance the timer to OPEN and break contacts in the timer. The timer is solely used as an off-board set of relay switches. Note: The timer motor is hard wired to timer cams 10T and 10B in the timer. TIMER 1A (120 VAC) PK19/P7(8) 0 1 0 1 1 1 0 0 0 1 1 0 TIM ER 1B (120 VAC) YL16/P7(7) 1 1 1 1 0 0 0 0 1 1 0 0 TIMER 2A (24 VDC) PU17/P3(3) 1 1 0 0 1 0 1 0 0 0 0 0 TIM ER 2B (24 VDC) BU18/P3(5) 0 0 0 0 0 1 0 1 1 1 0 0 CYCLE SEQUENCE PREWASH TUM BLE PREWASH DRAIN MAIN WASH TUM BLE LIGHT WA SH TUM BLE BLEACH DISPENSE RINSE TUMBLE SPIN 1 SPIN 2 SPIN 3 EXTRA RINSE DELAY IDLE Key: 0 = Input Signal Not Asserted 1= Input Signal Asserted There are conditions under which the machine control will shut the cycle down if the timer does not advance. During Extra Wash/Prewash: If the timer inputs do not change away from Prewash Tumble for 15 minutes, the machine control will open the line relay. During Main Wash: If the timer inputs do not change for 29 minutes, the machine control will open the line relay. During any increment when the machine control energizes the timer motor until it sees the timer inputs change: If the timer inputs do not change for 5 minutes with the timer motor continuously energized, the machine control will open the line relay. - - These varying delays are to allow the washer to progress through several increments where the timer inputs normally do not change. In these cases, the machine control energizes the timer motor for 30 seconds, which is its advance time. It does not look for a timer input change. 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-4 Machine Control The machine control microprocessor board is located in the control console, mounted to the rear panel. The board receives input from the timer, door latch and lock switches, and unbalance and selector switches on the console. It also communicates with the motor control board to facilitate the various cycles and drive the motor for optimum performance. Torque and speed of the motor are monitored through the motor control board. Prior to Series 17 Figure 2-3 Series 17 and After Figure 2-3b Both incoming and exiting voltage are monitored through the machine control board and the surrounding circuitry. The following table lists the voltages for the various terminals on the microprocessor board. If proper voltage is not present, check switches and wiring for any loose connections or open circuits by disconnecting the power supply and performing continuity checks of individual circuits. NOTE: Connector P5 is Neutral input and L1 input is the Line Relay Connector Comm (Gray wire), L1 output is Line Relay Connector Comm (Black wire). To check voltages from the board, turn timer dial to a wash cycle and press the start/off button. This will activate the L1 relay board and apply power on the machine control. 16008373-01 SECTION 2. ELECTRICAL COMPONENTS & TESTING © 1998 Maytag Corporation 2-5 FU N CTIO N M A C H IN E CON TROL BOARD T ERM IN A L/ W IRE P5 (W H11) M A C H IN E CON TROL BOARD T ERM IN A L/ W IRE P3/2 (PK 37) V O L T A G EAPP R O X . (W hen A ct i v a t e d ) 24 VDC T IM ER C O N TACT Permanent Press (Fab ric Sw i tch ) Delicates (Fab ric Sw i tch ) H a n d W ash (Fab ric Sw i tch ) C o t t on/ S t urd y (Fab ric Sw i tch ) N o t Inv o lv e d P5 (W H11) P3/6 (OR 38) 24 VDC N o t Inv o lv e d P5 (W H11) P3/8 (BR 39) 24 VDC N o t Inv o lv e d P5 (W H 1 1 ) P5 (W H 1 1 ) P5 (W H 1 1 ) P5 (W H 1 1 ) P3/2 (PK 37) P3/6 (OR 38) P3/8 (BR 39) P2/1 (PU 21) 0 VDC 0 VDC 0 VDC 24 VDC - O N 0 VDC - O FF 120 VA C N o t Inv o lv e d Signal O N / O FF ( O p t i o n s S w i t ch ) Extra Rin se ( O p t i o n s S w i t ch ) M ax Extract ( O p t i o n s S w i t ch ) Push To Start Sw it ch (When pressed) U nbalance C o nt r o l D o o r Lock - Sp in M ot o r Control & M a ch in e C o nt r o l H o t W ater V a l v e N o t Inv o lv e d P5 (W H 1 1 ) P7/8 (PK 19) 12B, 6B ,8T P5 (W H 1 1 ) P2/3 (Y L 20) 24 VDC N o t Inv o lv e d P5 (W H 1 1 ) P1/3 (RD 28) 120 VA C N o t Inv o lv e d P5 (W H11) P2/4 (OR 40) 24 VDC N o t Inv o lv e d P3 (1) P5 (W H11) P3/7 (Y L 36) LIN E RELA Y C O M (BK 27 or BK1) P7/1 (OR7) 24 VDC 120 VA C N o t Inv o lv e d N o t Inv o lv e d P5 (W H11) 120 VA C o r 500-10 0 0 O h m s 120 VA C o r 500-10 0 0 O h m s 120 VA C N o t Inv o lv e d C o ld W a t e r V a lv e P5 (W H11) P7/2 (BU 9 ) N o t Inv o lv e d D o o r Lock W a x M ot o r Bleach W a x M ot o r S o ft e n e r W ax M ot o r D e l a y L ight O n Li g ht (S e r ies 17) P5 (W H11) P7/4 (BR 14) N o t Inv o lv e d P5 (W H11) N o t Inv o lved 120 VA C 2T P5 (W H11) N o t Inv o lved 120 VA C 2B P5 (W H11) P5 (W H11) N o t Inv o lved P7/5 (RD 3) 120 VA C 120 VA C 4T N o t Inv o lv e d 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-6 DRIVE MOTOR The drive motor is a switched reluctance type motor. The basic operating principle of the switched reluctance motor is direct magnetic attraction between the stationary electromagnetic coils (stator) and a specially configured 2-4). rotor or armature (Figure 2-4) The rotor is comprised of stacked plates or laminations mounted on a center shaft. The shape of these laminations are characteristic of the switched reluctance motor. The rotor, when viewed from the end of the rotor, has "teeth" much like a gear. These "teeth", or pole pieces, are pulled as the result of direct current power through the stator coils. The following illustration shows the motor terminals for each of the coils involved. The letters with positive and negative symbols indicate the motor phase circuitry of the terminals. Motor Harness Connector Figure 2-5 Refer to section titled Motor Control for board identification of A, B and C terminal/harnesses (Figure 2-6). Also, see the wiring schematic for harness identification. MOTOR CONTROL BOARD Figure 2-4 Multiple stator coils are positioned around the rotor and are connected in three different phased "sets" of paired coils. Magnetic attraction causes the rotor poles to turn toward the coils. The electronic motor control board switches the magnetic field off as the rotor pole piece approaches; then, turns on another set of coils further ahead. It is this switching action of motor phases that determines direction and rotational speed of the rotor (and shaft). The motor control board changes the 120 VAC voltage line input to 170 VDC, and distributes the current phases to the stator coil sets in sequence to the drive motor. The motor control board receives 120 VAC voltage from the line cord and distributes DC voltage to the drive motor. The motor control converts the voltage from single phase to 3 phase for the drive motor. Another purpose of the motor control is to monitor the drive motor speed through a tachometer circuit linking the motor control board to a tachometer on the drive motor. This is a 3-wire circuit comprised of a Black, Blue and White wire harness. Failure of this circuit will cause the motor to start jerking in place or accelerate rapidly for up to 5 seconds. This occurs whenever the tachometer in the drive motor is trying to locate the proper shutter and sensor sequence. For example, if the tachometer signal is lost from the motor control to the machine control just prior to spin, the motor will ramp up for 5 seconds then stop. 16008373-01 SECTION 2. ELECTRICAL COMPONENTS & TESTING © 1998 Maytag Corporation 2-7 Control Test Motor & Motor Control Test 1. Set the timer knob into the delay increments. 2. Press the push-to-start switch to start the washer in the delay mode. Confirm the delay light is ON. 3. Check for 120 VAC between the L and N terminals (black wire no.27 and white wire no. 13) on the motor control board. If not present, check wiring between the machine control and the motor control boards. 4. Unplug the washer power cord. Test cord to the same board terminals. 5. Remove JP4 Interface connector wire harness on front end of motor control board. 6. Plug the washer power cord into a 120 VAC power source. The motor control will immediately execute a test routine and the motor should run, rotating the spinner at 50 rpm. 6. If the motor runs, and the spinner rotates at the proper RPM speed, the problem lies outside of the motor and motor control circuit. Disconnect power to the washer and reconnect the JP4 Interface connector to the motor control. 7. If the motor does not run: A. Check the 10-amp fuse located on the control board, either visually or with an ohm meter. If bad, completely replace motor control/wire harness assembly (Figure 2-6). B. If the fuse is functioning, visually check the six semiconductors on the heat sink for any damage. If damaged, replace motor control/wire harness assembly complete and check motor windings for damage (See Drive Motor). Replace motor if necessary(Figure 2-6) . (Figure C. If fuse and semiconductors show no visible damage, perform the motor phase test. 8. Unplug the washer power cord and replace motor control board connector JP4 when finished. Test Motor Phase Test It is possible for the motor to still run under light loads when one of the phases of the motor is nonfunctional. One possible symptom would be a "growling" noise from the motor. Torque is decreased when the motor is out of phase. This could result in a customer complaint that the load is not spinning out properly or it does not tumble consistently Tr with a large load (See Section 3: Tr oubleshooting). Figure 2-6 16008373-01 SECTION 2. ELECTRICAL COMPONENTS & TESTING © 1998 Maytag Corporation 2-8 To gain access to the motor control board terminals (Figure 2-6): 1 . Disconnect power to the washer prior to testing. 2 . Remove the two screws securing the motor control assembly to the base. Unsnap the two twist-lock wire ties restraining the motor to the motor control board harness base. 3 . Remove the green ground wire, line & neutral wires and the JP4 connector from the motor control board. 4 . Carefully lift the front end of the motor control board to disengage the rear locking tabs from the slots in the base. Slowly drag the motor control board, with motor harness attached, toward the front of the washer and place in front of the washer. 5 . Remove the screw securing the splash shield covering the face of the motor control board. Pivot the splash shield with top screw in the motor control board metal frame, allowing the plastic shield to become an electrical shield between the motor control board and the base. 6 . Reconnect the ground wire, line 1 and neutral wires. Leave the JP4 connector off the board (Figure 2-6). 7 . Place the timer knob into the delay increments. 8. Plug the power cord into the wall socket and press the push-to-start button. Check Phase C by disconnecting the yellow or orange wire at the motor control board. If the motor operates with a slight growling sound, phases A and B are operating correctly. Reconnect phase C and test with phase B disconnected. If the motor does not run properly, phase A or B is not functioning. Perform the motor windings check (See Motor Windings Check). 10. Check Phase B by disconnecting the white or red wire at the motor control board. If the motor operates with a slight growling sound, phases A and C are operating correctly. Reconnect phase B and test with phase A disconnected. If the motor does not run properly, phase A or C is not functioning. Perform the motor windings check (See Motor Windings Check). Motor Windings Check 1 . Disconnect power to the unit. 2 . Remove each pair of phase wires from the motor control and perform an ohm check of each wire leading to the motor. Each wire pair should show 2-3 ohms resistance (Figure 2-5). 2 . There should be no continuity between any of the terminals and the frame of the motor. 3 . Check that all six motor terminals are secure and at the same height in the connector housing. Replace motor if terminals are pressed into the motor. 4 . Remount the six-position motor connector onto the motor. Reassemble the drip shield cover onto the motor control. 5 . Reposition the motor control into the washer when finished. Make sure the two screws and the twistlock wire ties are fastened properly to the wire harness. 9. 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-9 PHASE C WIRE COLORS Yellow or Orange MOTOR CONDITION Runs Does Not Run RESULT/SOLUTION -Phases A&B are operating correctly. (Check Phase A and B) -Phase A or B is non-functional. (See Step 10) -Phases A&C are operating correctly. (Check Phase A and C) -Phase A or C is non-functional. (See Step 10) -Phases B&C are operating correctly. (Check Phase B and C) -Phase B or C is non-functional. (See Step 10) B White or Red Runs Does Not Run A Black or Blue Runs Does Not Run Circuit Tachometer Circuit Diagnostics The tachometer system of the motor is comprised of a plastic wheel, called a shutter, and an optical sensor (Figure 2-9). The shutter is mounted to the end of the motor shaft under the plastic endbell covering of the motor. The edge of the shutter resembles a "picket fence" with different size "pickets." The pattern consists of six different "pickets" which are repeated eight times. An optical sensor is mounted to one side of the shutter and monitors the "pickets" as they pass through the sensor. As the "pickets" pass through the sensor field, signals are generated and transmitted to the motor control board through the tachometer wire harness (Figure 2-10 and 2-11). Figure 2-9 Figure 2-10 16008373-01 SECTION 2. ELECTRICAL COMPONENTS & TESTING © 1998 Maytag Corporation 2-10 The following table indicates voltage checks of the tachometer harness between the motor and motor control board. Tachometer Wire Checks White to Black (From Motor Control) Voltage Found Condition Of Component Good Motor Control Board Bad Motor Control Board 11 VDC (± 2.5 VDC) White To Black (From Motor 0 VDC Control) Figure 2-11 White To Black + 13 VDC or (From Motor <9 VDC Control) Blue to Black (From Drive Motor) No change in DC volts as motor is turned slowly Bad Motor The motor control monitors the signals and communicates this information to the machine control. The purpose of this signal is to tell the motor when to energize each winding in the motor and to tell the machine control the actual motor speed. Note: If the machine control board does not receive an input signal from the motor control/tachometer circuit (JP4 connector), the motor speed will rapidly accelerate for 5 seconds then shut down. The machine control will sense a "locked rotor" condition and the motor will stop. If the motor control does receive from motor, not r eceive an input signal from the motor, the motor will "jerk" for 5 seconds then shut down. 1. Inspect the motor control wire harness for integrity of the connections on both ends. The harness is comprised of a White, Blue and Black wire. 2. Set the washer into the Delay Wash cycle and press the start/off button. The unit will start without activating the motor. Leave the tachometer harness on the motor control and insert the meter probes into the back side of the tachommeter harness. Bad Motor Blue to Black (From Drive Motor) Voltage changes from 0 - 5 VDC volts as Good Motor motor is turned slowly. UNBALANCE CONTROL SYSTEM The unbalance control system is comprised of the inertial switch, outer tub displacement switch, strut displacement switch and a cabinet vibration sensor mounted to the machine control board. The three switches are wired in series on a 24 VDC circuit, monitored by the machine control board. The sensor is mounted on the machine control board. Software in the machine control board will begin monitoring the switches when the spin speed reaches 90 rpm. The inertial unbalance switch monitors outer tub vibrations above 150 rpm. Inside the door is a cabinet vibration absorber designed to counter the vibration of the tub and serve as a tuned absorber for the whole washer. 16008373-01 SECTION 2. ELECTRICAL COMPONENTS & TESTING © 1998 Maytag Corporation 2-11 Whenever a displacement switch is tripped, the machine stops and redistributes the clothes load. This involves a three (3) second pause, followed by a five (5) second reverse tumble (47-49 rpm) to redistribute the clothes load. The washer will pause again for three (3) seconds, then start the distribution profile again. To redistribute the load, the machine tumbles the load (50-90 rpm) and again attempts to pass through critical (about 150 rpm). The machine will try to redistribute twice as the washer attempts to spin at 800 rpm. Once the load is properly redistributed and the speed reaches above 500 rpm, the inertial switch and cabinet vibration sensor are used. If the inertial switch or sensor is activated, the washer will drop in spin speed. This is based upon the speed at which switch activation takes place. See Figure 2-12 outlining the spin speed categories and the corresponding reduced speeds. If the switches are not activated, the final spin speed will reach a maximum of 850 rpm and then drop to find the optimum performance level, based upon readings taken by the cabinet vibration sensor. Consumers may be confused by the upand-down cycling of the motor. However, the machine is searching for the optimal speed performance. Tub Displacement Switch The tub displacement switch is located on the upper right hand side of the outer tub, below the top concrete weight, between the outer tub and the cabinet. The switch senses the outer tub touching the cabinet side as the machine passes through critical. When this switch is tripped, the machine stops and redistributes the load. Testing the Tub Displacement Switch: 1 . Disconnect power to the unit. 2 . Place ohm meter leads across the two terminals of the switch. Depress the button on the switch. If the contacts open, the switch is good. If not, replace the switch. Strut Displacement Switch The strut displacement switch is clipped to the top of the left rear strut. The switch senses the outer tub bottoming out on the strut as the machine accelerates above 90 rpm. This is caused by the twisting motion of the outer tub. This additional switch is required because the twisting motion may not trip the outer tub displacement switch. The primary cause for activation would be an unbalance at the front and rear of the spinner on opposite sides. The strut displacement switch is wired in series with the tub displacement switch and causes the same type of redistribution. Testing the Strut Displacement Switch: 1 . Disconnect power to the unit. 2 . Place ohm meter leads across the two terminals of the switch. Depress the button on the switch. If the contacts close, the switch is good. If not, replace the switch. RPM FUNCTION 4 7 ...........................T u m b l e 47-85 .......................Distribution 90-250 .....................Accelerate Through Critical 250-499 ..................Accelerate Through Critical 500-575 ..................High Speed Acceleration - WILL DROP TO 450 RPM 600-675 ..................High Speed Acceleration - WILL DROP TO 555 RPM > 6 7 5 .......................High Speed Acceleration - WILL DROP TO 650 RPM 750-800 ............. TOP SPIN SPEED Figure 2-12 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-12 Inertial Unbalance Switch The inertial unbalance switch is located on the upper right hand side of the outer tub, in front of the top concrete weight. The switch consists of a moving weight in the switch body which presses against the switch contacts. If the unbalance of the outer tub becomes too erratic, the moving weight will open the contacts in the switch. When the machine controller senses the switch opening, the machine controller will reduce the spin speed to 650, 550, or 450 rpm depending on the current speed closest to the level spin speed (i.e. 625 rpm trip would drop to 550 rpm) (See Figure 2-12). Testing the Inertial Unbalance Switch: Testing of the switch may prove difficult. The switch will not open unless the switch is moved side to side creating a "G" force of 8 - 9 Ft. lbs. 1 . Disconnect power to the unit. 2 . Place ohm meter leads across the two terminals of the inertial switch. Move the switch side to side. If the contacts do not open easily, the switch is good. If the switch contacts are open or easily tripped, replace the switch. spring rate of the absorber; and changes in the pulley-belt ratio. It can also change from run to run due to the size of the clothes load and type of floor. The sensor finds the optimum speed on every run. The optimum speed is between 750 and 850 rpm. Cabinet Vibration Absorber This is a tuned absorber mounted in the door. The tuned absorber consists of a mass suspended by springs tuned to vibrate at approximately 800 rpm. The mass vibrates 180 degrees out of phase with the vibration of the cabinet. This cancels out much of the vibration caused by the clothes load at 800 rpm (See Section 5: Cabinet Assembly). Cabinet Vibration Sensor The cabinet vibration sensor is mounted to the lower left corner of the machine control board. This is a piezo-electric strip mounted to the machine control board. With a mass attached to the end of the strip, the machine controller monitors the cabinet vibration as the machine reaches top speed. The machine controller uses the vibration sensor to attempt to spin the washer at the optimum speed with the least amount of vibration. Optimum speed changes from machine to machine due to: changes in mass of the absorber; changes in 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-13 16008373-01 SECTION 2. © 1998 Maytag Corporation ELECTRICAL COMPONENTS & TESTING 2-14 SECTION 3. TROUBLESHOOTING OFF: Washer Runs Five Minutes Then Shuts OFF : During the wash cycle, the machine control communicates with the timer, via the timer input circuits. If the machine control board does not see a change in timer inputs over a period of 5 minutes, it will open the line relay and shut the washer off. Check the timer input circuits for poor connections at the timer and the machine control board. Replace timer if necessary (See Section 2: Timer Input Circuits). Shuts OFF In The Middle Of The Spin Cycle: During the spin cycle, the machine control monitors the door lock mechanism to ensure the door is locked. This is done through the door lock enable switch. During "lock mode," the shaft of the door lock mechanism is pressed forward by the door lock wax motor, and the shaft presses in the button of the door lock enable switch. If the machine control board sees the switch OPEN during the spin cycle, the machine control board will automatically shut the washer OFF. This is caused by a weak spring in the door lock wax motor. Replace the complete door lock mechanism. Warning - Always shut off electrical power to the unit before beginning any service repair procedures. Shuts OFF When Push-To-Start Button Released: Check for proper wiring of BK 27 to COMM and GY 26 to NO. If reversed, the washer will shut off when button is released. If wiring is proper, replace machine control board. Line relay may be bad (See Section 1: Push-ToStart Line Relay Operation). Runs For Five Seconds Then Shuts OFF: Suspect a communication problem between motor, the motor control board and the machine control board. Check the motor and motor control system by removing the JP4 connector on the motor control board. Set the timer dial into the delay cycle and then press the push to start switch. If the motor operates and the washer goes into a 50 rpm tumble, then the source of the problem is the RD 30 wire leading from the motor control to the P4(2)/RD30 connector on the machine control board. When the machine control tells the motor control to run the motor, it monitors the red wire to determine if the motor is actually running. If the board does not see a return signal, the washer will shut down. If RD30 wire is making contact, then suspect possible problems with timer input circuits. (See the following section on Machine Operation Does Not Match Cycle Description): Shuts OFF During Final Rinses: The machine control board is programmed to allow a maximum continous fill time of six minutes or an accumulated fill time of 8 minutes for each full wash cycle. If the required fill time exceeds the time limit, the washer will shut down. This is to prevent flooding in the event there is a loose hose clamp or damaged air dome hose. Check the incoming water lines for a minimum pressure of 20 psi. If lower, the customer can use smaller clothes loads and reduce the pressure to 10 psi. An alternative solution would be to change the plastic inlet screens to metal screened washers and remove the nozzle extender found in the water valve inlet hose near the dispener inlet. SECTION 3. TROUBLESHOOTING