tech-sheet-8206648
Tech Sheet Do not discard

WARNING

Electrical Shock Hazard Disconnect power before servicing. Replace all parts and panels before operating. Failure to do so can result in death or electrical shock.

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE

MICROWAVE ENERGY

a. Do not operate or allow the oven to be operated with d. Any defective or misadjusted components in the the door open. interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, b. Make the following safety checks on all ovens to be replaced, or adjusted by procedures described in serviced before activating the magnetron or other service manual before the oven is released to the microwave source, and make repairs as necessary: owner.

1. Interlock Operation e. A microwave leakage check to verify compliance with the Federal Performance Standard should be 2. Proper Door Closing performed on each oven prior to release to the owner.

3. Seal and Sealing Surfaces (Arcing, Wear and Other f. Do not attempt to operate the oven if the door glass is Damage) broken.

4. Damage to or Loosening of Hinges and Latches 5. Evidence of Dropping or Abuse

c. Before turning on microwave power for any service test or inspection within the microwave generating compartments, check the magnetron, waveguide or transmission line, and cavity for proper alignment, integrity and connections.

8206648 / 4619-651-99641 FOR SERVICE TECHNICIAN’S USE ONLY

2

Primary

Fuse Interlock

20 Amp Switch

W BK BR

W OR R

120V/125V, 60Hz Monitor Electronic HL Relay HL Relay HF Triac H.V. Interlock Control Board 7103 Transformer (1) AC Line Filter (3) Switch 4911 4912 2 1 L1 Fuse HF OR / BK R 4201 Relay CL/SM/CF Down Magnetron 4905 FA W L.V.T. Relay 5100 HF F R P4 Prim. Relay 4901 WIRING DIAGRAMS NFS 4902 Schematic DiagramOR / R

L BK Cy Sec. Diode 6106 TTM Microwave R / WR Relay Relay 4903 W G Coil 4906 Y/G GND R Cx GND W NW R Cy G N1 HL L1 FT HF2 HF1 Door F/L TTM FR FT BK

1 P3 1 P2 1 P1 1 H.V. Capacitor

Y/G W Y W W 4P5 W

HL HL BR BU BK 1P6 BK R BU GY BU 5P5 Exhaust Fan W W Humidity G HF Sensor Thermostat BU BU H.V. Diode Y Y Y/G

(4) N1 R R Power Up 5P6 W (2) R Motor Resistor Capacitor

Golden W R 1P5 W tab R CL BK SM CF 2P5 W GY Magnetron BR White tab Thermostat TT

BU W W

Cavity Cavity Cavity Secondary BU Thermostat 1 Thermostat 2 Thermostat 3 Interlock W Switch BU BU BU

Condition: Door Open CF Cooling Fan Motor BK P1/P2/P3/P4/P5/P6: Connectors DWG No. MU-090 Symbol Notes TT Turntable Motor SM Stirrer Motor W HF Hood Exhaust BK: Black W: White BR: Brown BU Wire Color – Blue CL Cavity Lamp Fan Motor BU BU: Blue G: Green OR: Orange Hood Y HL (Cooktop) Lamp R R: Red Y: Yellow GY: Gray

Parts Layout (not to scale)

B A

C

BB D AA E

Z

SCALE 4:5 F

O G

P H

Y I X J W V K A. Cavity thermostat 3—opens at 329ºF U (165ºC), closes at -31ºF (-35ºC) T L S M B. Humidity sensor N C. Hood exhaust fan motor R O D. Cavity thermostat 2—opens at 257ºF P Q (125ºC), closes at -31ºF (-35ºC) E. Cavity thermostat 1—opens at 257ºF I. Magnetron thermostat—opens at S. Touch panel 257ºF (125ºC), closes at 185ºF (85ºC) T. Exhaust fan thermostat—opens at (125ºC), closes at -31ºF (-35ºC) F. AC line filter J. Cooling fan motor 113ºF (45ºC), closes at 140ºF (60ºC) G. Power resistor K. H.V. transformer U. Secondary interlock switch H. Magnetron L. H.V. capacitor V. Monitor interlock switch M. H.V. diode W. Primary interlock switch N. Line fuse (20 amp) X. Turntable motor O. Hood (cooktop) lamp holders Y. Cavity lamp holder P. Hood (cooktop) lamps Z. Cavity lamp Q. Fuse holder AA. Motor capacitor R. Electronic control BB. Stirrer motor

3

Primary, Secondary, and Monitor Interlock Switch Checkout Procedure

Switch Check By3 Door Open Door Closed

Primary 1. Unplug microwave oven or disconnect power. – +

Interlock 2. Disconnect the wires at the Primary Interlock Switch.

3. Check from the common terminal (black wire) to the normally open terminal

(brown/white wires).

1. Unplug microwave oven or disconnect power. + –

2. Disconnect the wires at the Primary Interlock Switch.

3. Check from the common terminal (black wire) to the normally closed terminal

(orange wire).

Secondary 1. Unplug microwave oven or disconnect power. – +

Interlock 2. Disconnect the wires at the Secondary Interlock Switch.

3. Check from the common terminal (blue/black wires) to the normally open

terminal (white/blue wires).

Monitor 1. Unplug microwave oven or disconnect power. + –

Interlock 2. Disconnect the wires at the Monitor Interlock Switch.

3. Check from the common terminal (white wire) to the normally closed terminal

(red wire).

(+) Continuity (-) No Continuity

NOTE: These diagrams are not intended to show a complete circuit; they represent the position of switches during “DOOR OPEN” or “DOOR CLOSED” (continuity checks only).

Door Closed Door Open

L N L N (NC) (NO) (NO) (NC) (NO) (NC) (NO) (NO) (NC) (NO)

Primary Monitor Secondary Primary Monitor Secondary Interlock Interlock Interlock Interlock Interlock Interlock Switch Switch Switch Switch Switch Switch

4

TROUBLESHOOTING

Do not continue with the diagnostics of appliance if the 3. Disconnect white wire from power transformer and household fuse is blown, a circuit breaker is tripped or if there discharge high-voltage capacitor. is less than 120-volt power supply at the wall outlet. 4. All testing must be done with an ohmmeter having a Complete the following steps before checking microwave sensitivity of 20,000 ohms per volt DC or greater, and oven circuitry: powered by at least a 9-volt battery.

1. Unplug microwave oven or disconnect power. 5. All operational checks using microwave energy must be done with the microwave oven loaded with a minimum of 2. Check for loose wiring or incorrect wiring within 10 oz (300 mL) of water in a microwave safe container. microwave oven.

Microwave Cooking

R BR 2P3 Electronic Control 1P4 G BR L.V. Magnetron Transformer OR 5100 Thermostat Secondary Cavity L1 Fuse 6P3 Fuse High Voltage Interlock Thermostat 3 4201 Switch Filter 20 Amp System MW Relay W BK W BK BR 2 4903 1R W BU BU

Primary TTM Relay Cavity 4906 Thermostat 2 Interlock Turntable CL/SM/CF Relay Motor Switch 4901 BU 2P2 R R R BU 1P5 TT BK Cavity Cavity Thermostat 1 2P5 Lamp CL GY W

Cooling W BU Fan Stirrer SM 1P2 GY CF Motor

W Filter

N W

Hood Exhaust Fan Turns on High Automatically While at Off or Speeds 4 or 3

Electronic Control Cavity Thermostat 3 L1 Filter Fuse Fuse L.V. Cavity 20 Amp 4201 Transformer Thermostat 1 Filter N BK W R BR 5100 BU 2P3 1P4 G BR BK BU BU BU W

BU Cavity

Thermostat 2

Hood Exhaust HF Relay BK 1P6 BK Fan Thermostat 4902 5P3 BU 3P3 4P3 W W HF Hood Exhaust Fan Motor Motor BU Capacitor Y Y

R R

5P6

5

Hood Exhaust Fan Turns on Low Automatically While at Speeds 2 or 1

Electronic Control

L1 Filter Fuse Fuse L.V. Cavity Cavity 20 Amp Thermostat 3 4201 Transformer Thermostat 1 Filter N BK W R BR 2P3 BU 5100 1P4 G BR BK BU BU BU W

5P3 BU Cavity 4P3 Thermostat 2

Hood Exhaust HF Relay BK 1P6 BK Fan Thermostat 4902

BU W W Hood Exhaust 3P3 BU H F Fan Motor Motor Capacitor Y

Y

R R

5P6

Hood Exhaust Fan Turns on (Speeds 4 & 3 Manually)

Electronic Control Cavity

L1 Filter Fuse Fuse L.V. Cavity Thermostat 1 20 Amp Thermostat 3 4201 Filter N Transformer BU BK W R BR 5100 1P4 G BR BK BU BU BU W 2P3

BU Cavity

HF Triac Thermostat 2 7103 5P3 BK 1P6 BK

4P3 W W HF Hood Exhaust Fan Motor HF Relay HF Relay Motor BU

4905 4902 Capacitor Y Y

R R

5P6

Hood Exhaust Fan Turns on (Speed 2 Manually)

Electronic Control Cavity

L1 Filter Fuse Fuse L.V. Cavity Thermostat 1 20 Amp 4201 Transformer Thermostat 3 Filter N

BK W R BR 2P3 5100 1P4 G BR BK BU BU BU BU W

BU Cavity

HF Triac Thermostat 2 7103 5P3 BK 1P6 BK

4P3 W W HF Hood Exhaust Fan Motor HF Relay HF Relay Motor BU Capacitor 4905 4902 Y Y

R R

5P6

Hood Exhaust Fan Turns on (Speed 1 Manually)

Electronic Control Cavity

L1 Filter Fuse Fuse L.V. Cavity Thermostat 1 20 Amp 4201 Thermostat 3 Transformer Filter N BU BK W R BR 2P3 5100 1P4 G BR BK BU BU BU W

BU Cavity Thermostat 2

HF Triac BK 1P6 BK 7103 Power Resistor 5P3 W W Hood Exhaust W 3P2 HF Relay BU H F Fan Motor 4905 4P3 Motor W 4P2 HF Relay Capacitor Y

4902 Y

R R

5P6

6

Microwave Plugged In—Time of Day Displayed

L1 Filter Fuse Electronic Control Cavity Cavity 20 Amp Thermostat 3 L.V. Thermostat 1 Filter N BR 2P3 Transformer BU BK W R 1P4 G BR BK BU BU BU W 5100 Cavity Fuse Thermostat 2 4201

Door Open—Oven Cavity Light Is On

L1 Filter Fuse Electronic Control Cavity Cavity 20 Amp Thermostat 3 L.V. Thermostat 1 BK W R BR 2P3 Transformer 1P4 G BR Filter N BK 5100 BU BU BU BU W Cavity OR 6P3 Fuse Lamp CL Cavity 4201 Thermostat 2 BK CL/SM/CF Relay 1P2 GY W 4901

Primary Interlock

Switch

Cooktop Light on High

Electronic Control

L1 Filter Fuse Fuse L.V. 20 Amp 4201 Transformer Cavity Cavity BK W R BR 2P3 G 5100 1P4 BU Thermostat 3 Thermostat 1 Filter N

W BR BK BU BU BU BU W Y Hood BU 5P5 Cavity HL Relay (Cooktop) Lamp HL Thermostat 2 4911 W HL

HL Relay Diode 4P5 Hood (Cooktop) Lamp 4912 6106

1P3

Cooktop Light on Low (Night Light)

Electronic Control

L1 Filter Fuse Fuse L.V. Cavity Cavity 20 Amp 4201 Thermostat 3 Transformer BK W R BR 2P3 G Thermostat 1 Filter N 5100 1P4 BU

BR BK BU BU BU BU W

HL Relay Hood BU 5P5 Cavity W HL Thermostat 2 4911 (Cooktop) HL Lamp

HL Relay Diode W 4P5 Hood (Cooktop) Lamp 4912 6106 Y 1P3

7

Touch Panel

Touch Panel and Electronic Control Test

The microwave hood combination is provided with a self-diagnostic routine that can be accessed through the touch keypad.

To initiate this routine: 4. After pressing each button on the control panel, “8” will 1. Press and hold CANCEL/OFF while opening the door. appear in the display to indicate that the circuits are complete and all relays are working. Refer to Key Table 2. While still holding the CANCEL/OFF button, unplug the for Test Mode. microwave oven for 2 seconds, then plug it back in. NOTE: If the CANCEL/OFF button is pressed during this 3. Release the CANCEL/OFF button and close the door. diagnostic routine, you will exit the test mode.

Key Table for Test Mode NOTE: Display position “1” is farthest to the left. Display position “5” is farthest to the right.

Key Name Display Key Name Display In Circuit Relay Position* In Circuit Relay Position*

Popcorn – 1 6 Relay 4906 & 5/CL

Relay 4901

Baked Potato – 2

7 – 1

Meal Reheat – 3

8 Relay 4912 2

Reheat – 4

9 Hood Fan Triac— 3

Cook Humidity Sensor Sxxxx Relay 4902 &

Relay 4905

Defrost – 1 Clock Buzzer 4/Buzzer

Cook Time – 2 0 – 5

Cook Power – 3 Timer – 1

Keep Warm – 4 Add a Minute – 2

1 Relay 4901 5/CL Start – 4

2 Relay 4911 1/HL Cancel/Off (to lock, hold Exit Test Mode – for 5 seconds) 3 Relay 4903 2/MW

4 – 3 Light On/Night/Off – 1

5 – 4 Vent Fan 5 Speeds – 2

*”8″ will appear in the display position indicated in the Turntable On/Off – 3 table. *”8″ will appear in the display position indicated in the *After 8 seconds, Hmxxx will be displayed (xxx represents table. humidity reading).

8

Microwave Oven Power Output Test

1. Place 8 oz (250 mL) of lukewarm water in the center of the NOTE: If the water takes longer than 2 minutes to heat, microwave oven. this may indicate either the operating voltage is lower than 110 volts or there is a problem with the microwave 2. Operate on HIGH power level for 2 minutes. Water oven. should be hot.

Failure Codes Indications

NOTE: Many of the problems listed in the chart below may be solved by power cycling: unplug microwave oven or disconnect power. After one minute, plug in microwave oven or reconnect power.

Display Likely Failure Condition Recommended Repair Procedure Flashing Power failure colon “:” Touch panel failure After a power failure, the colon “:” will be flashing. Press any key to end this F2 indication. The colon will then be steady when in standby. Humidity sensor failure F3H 1. Unplug microwave oven or disconnect power. MW relay 2. Replace touch panel. F6 3. Replace all parts and panels before operating. 4. Plug in microwave oven or disconnect power. 5. If problem persists, unplug microwave oven or disconnect power. 6. Replace electronic control. 7. Replace all parts and panels before operating. 8. Plug in microwave oven or reconnect power.

1. Unplug microwave oven or disconnect power. 2. Connect a new humidity sensor to the electronic control (at P1). 3. Replace all parts and panels before operating. 4. Plug in microwave oven or reconnect power. 5. If no failure code appears when starting sensor function, unplug

microwave oven or disconnect power. 6. Replace humidity sensor. 7. Replace all parts and panels before operating. 8. Plug in microwave oven or reconnect power. 9. If failure code appears when starting sensor function, unplug

microwave oven or disconnect power. 10. Replace electronic control. 11. Replace all parts and panels before operating. 12. Plug in microwave oven or reconnect power.

1. Unplug microwave oven or disconnect power. 2. Check wiring to Relay 4903. 3. Check to see if the relay (4903 on relay control board) contact has

welded closed. 4. Replace all parts and panels before operating. 5. Plug in microwave oven or reconnect power. 6. If problem persists, unplug microwave oven or disconnect power. 7. Replace electronic control. 8. Replace all parts and panels before operating. 9. Plug in microwave oven or reconnect power.

9

Component Tests

IMPORTANT:

s Unplug microwave oven or disconnect power. s Check that all wire leads are in the correct positions before operating the microwave oven. s Remove the lead wires from the related component before conducting any of the following tests. s Grasp wire connectors when removing the wire leads from microwave oven parts. s All operational checks using microwave energy must be done with the microwave oven loaded with a minimum s All testing must be done with an ohmmeter having a of 10 oz (300 mL) of water in a microwave safe sensitivity of 20,000 ohms per volt DC or greater, and container. powered by at least a 9-volt battery.

s Conduct a microwave energy test after performing any tests or repairs to the microwave oven.

Components Test/Results

H.V. Transformer 1. Unplug microwave oven or disconnect power. 2. Remove wire leads. Filament 3. Measure resistance (ohmmeter scale: Rx1): (orange/red wires) s Primary winding: Less than 0.5 ohm (approximate) Primary (black wire) s Secondary winding: 60 ohms (approximate) s Filament winding: 0 ohm Primary (blue wire) 4. Measure resistance (ohmmeter scale: Rx1k): Secondary s Primary winding to grounding: Normal: Infinite (yellow/white wires – s Filament winding to grounding: Normal: Infinite ground to transformer case)

Magnetron 1. Unplug microwave oven or disconnect power. 2. Remove wire leads. Check that the seal is in good condition. 3. Measure resistance (ohmmeter scale: Rx1):

s Filament terminal: Normal: Less than 1 ohm

4. Measure resistance (ohmmeter scale: Rx1k): s Filament to chassis: Normal: Infinite

H.V. Capacitor 1. Unplug microwave oven or disconnect power. H.V. Diode 2. Discharge capacitor. 3. Measure resistance (ohmmeter scale: Rx1k):

s Terminal to terminal: Normal: Momentarily indicates several ohms, gradually returns to Infinite.

s Terminal to case: Normal: Infinite

1. Unplug microwave oven or disconnect power. 2. For ohmmeters without a 9-volt battery, prepare the DC 9-volt battery and

10k ohms resistor in series including wire leads. 3. Connect the DC 9-volt battery to the H.V. diode. 4. Measure continuity (ohmmeter scale: Rx10k):

s Forward direction: Normal: 5-6 volts (approximate), Abnormal: Open—9 volts (approximate), short—0 volt (approximate)

s Reverse direction: Normal: 9 volts (approximate), Abnormal: Open—9 volts (approximate), short—0 volt (approximate)

NOTE: Some inexpensive ohmmeters do not have a 9-volt battery incorporated in them, and may indicate infinite resistance in both directions when testing the diode. It is recommended that you use an ohmmeter with a 9-volt battery on the 10x scale to properly test the H.V. diode.

10

Components Test/Results Turntable Motor/Stirrer Motor 1. Unplug microwave oven or disconnect power. Humidity Sensor 2. Remove wire leads. W 3. Measure resistance (ohmmeter scale: Rx1k): R BK s Turntable Motor: Normal: 2.7k-3.8k ohms (approximate); Abnormal: Infinite s Stirrer Motor: Normal: 2.7k-4.2k ohms (approximate) Resistor Cooling Fan Motor 1. Unplug microwave oven or disconnect power. 2. Remove the 3-pin connector from electronic control (P5). Power Resistor NOTE: Do not remove the attached resistor, which is used for internal Hood Exhaust Fan Motor resistance calibration. 3. Measure resistance across pins 1 & 3, and across pins 2 & 3 (ohmmeter scale: AC Line Filter Rx1k): s Normal: 2.8k ohms (approximate) at 77ºF (25ºC) +/- 18ºF (-10ºC) 1 2 s Abnormal: Infinite

3 1U 2 1. Unplug microwave oven or disconnect power. 2. Remove wire leads. L N 4 3. Measure resistance (ohmmeter scale: Rx1):

3 4 s Normal: 90-135 ohms s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance (ohmmeter scale: Rx1):

s Normal: 37-45 ohms s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance (ohmmeter scale: Rx1):

s High Speed—Normal: Red (R) and Blue (BU) wires: 79-119 ohms (approximate); Blue (BU) and Black (BK) wires: 22-43 ohms (approximate)

s Abnormal: Infinite s Low Speed—Normal: Red (R) and Blue (BU) wires: 79-119 ohms

(approximate); Blue (BU) and White (W) wires: 43-62 ohms (approximate) s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance (ohmmeter scale: Rx1):

s Normal: 1-3 (coil): Less than 1 ohm; 2-4 (coil): Less than 1 ohm; 3-4 (resistor): 550k-800k ohms

s Abnormal: Infinite

Thermostats NOTE: Refer to “Parts Layout” for opening and closing temperatures. 1. Unplug microwave oven or disconnect power. Cavity 2. Remove wire leads. Thermostat 3. Measure continuity (ohmmeter scale: Rx1):

Magnetron s Cavity and Magnetron Thermostats: Normal: Continuity; Abnormal: Infinite Thermostat s Exhaust Fan Thermostat: Normal: Infinite; Abnormal: Continuity Exhaust Fan Thermostat

11

8206648 / 4619-651-99641 8/06 FOR SERVICE TECHNICIAN’S USE ONLY