tech-sheet-8205886
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.

8205886 / 4619-651-98971 FOR SERVICE TECHNICIAN’S USE ONLY

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Monitor Primary Interlock Switch Fuse Interlock

20AMP Switch 4OR

2BK 6BK 7BR

5W

1BK Electronic Control

MW-Relay

AC Line Filter L.V. 4903 Transformer 2 1

L BK U1 L3 CL HF Triac HL Relay HL Relay Red Tube Relay 7103 4911 4912 Black Tube 4901 L 3BR 33K 8BU Pri. 33KSec. WIRING DIAGRAMS 68K 1 Down Schematic Diagram

Cy R 31R(HV)

GND Y/G 2 G GND R Cx HF Relay Diode White C 4902 6106 TTM Tube Relay 4906 H.V.Capacitor

Cy TTM CL L HF2 Door HF1 HL N1 NFS Hood H.V.Diode N4 1 P2 P3 1 Thermistor N W U2 L 30Y/G 14G 16GY 25BK 5P5 F FA Magnetron 17R 15Y HL 4P5 18R H.V. 1P5 (Golden 1P6 20R 21W Transformer terminal) BK

CL (White ) 26W W HF Up terminal 10BU BU

9BU TTM 27Y Y 13BU

11W Motor 28R R 19W Capacitor 5P6 2P5 22W 23BU Magnetron Thermostat

12W 24BU 29W

Cavity Secondary DWG NO. MU-074 Thermostat Interlock Switch P1/P2/P3/P4/P5/P6: Connectors Hood Exhaust BK Fan Motor R: Red W: White BR: Brown

Condition: Door Open HL Hood(Cooktop) Lamp W HF Y: Yellow G: Green BU: Blue Symbol Notes CL Cavity Lamp BU TTM Turntable Motor OR: Orange GY: Gray BK: Black

Y 1BK

R Wire Color-Black

Wire NO.-1

Parts Layout

(not to scale)

A

V B

C D

E

F G

S P5 H U 3551 I TS J RQ P O K

N L M

A. Hood exhaust fan motor L. Line fuse (20 amp) B. H.V. capacitor M. Power display PCB C. AC line filter N. Electronic control D. Magnetron O. Touch panel E. Magnetron thermostat—opens at 257ºF (125ºC), closes at 185ºF (85ºC) P. Secondary interlock switch F. Cavity thermostat—opens at 221ºF (105ºC), closes at -31ºF (-35ºC) Q. Monitor interlock switch G. H.V. transformer R. Primary interlock switch H. H.V. diode S. Lamp holders I. Hood thermistor T. Hood (cooktop) lamp J Motor capacitor U. Turntable motor K. Fuse holder V. Cavity lamp

Primary, Secondary, and Monitor Interlock Switch Checkout Procedures

Switch Check By Door Open Door Closed

1. Unplug microwave oven or disconnect power. – + 2. Disconnect the wires at the Primary Interlock Switch. Primary 3. Check from the common terminal (black/brown wires) to the Interlock normally open terminal (black/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/brown wires) 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/white wires) to the normally open terminal (blue wires).

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Primary, Secondary, and Monitor Interlock Switch Checkout Procedures

Switch Check By Door Open Door Closed

1. Unplug microwave oven or disconnect power.

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

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

closed terminal (blue wires).

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

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

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 8 oz (250 mL) of water in a microwave safe container. microwave oven.

Microwave Cooking

BR 5P2 Electronic Control 1P3 G 4P5 BU L.V. Magnetron Transformer Fuse OR Thermostat Cavity MW Relay Thermostat L Filter 20AMP 3P2 4903 H.V. Secondary Interlock BK BK TTM Relay Transformer 4906 1 BR W Switch BK BK 2 W BU CL Relay BU Primary 4901 Interlock Turntable Switch Motor

RR W BU 7P2 TT

1P5 2P5 W Filter Cavity N Lamp W

CL 6P2 GY

HF Triac 2P2 1P6 7103 BK BK 4P2 HF Relay WW

4902 BU BU HF

Y Y

RR

5P6 Motor Capacitor

4

Hood Exhaust Fan On High Automatically

Fuse Electronic Control Cavity Thermostat L Filter 20AMP L.V.

BK BK BK BR Transformer 1P3 G 4P5 BU W BU 5P2

W

HF Triac 1P6 BK BK 7103 2P2

HF Relay BU BU HF Filter N 4902 W Y Y

Hood RR Thermistor 5P6 Motor Capacitor

Hood Exhaust Fan On Low Speed

Fuse Electronic Control Cavity Thermostat L Filter 20AMP L.V.

BK BK BK BR 5P2 Transformer G 4P5 BU W BU

1P3

W

HF Triac W 2P6 W HF Filter 7103 BU BU N 4P2 W HF Relay Y Y

4902

RR

5P6 Motor Capacitor

Hood Exhaust Fan On High / Medium

Fuse Electronic Control Cavity Thermostat L Filter 20AMP L.V.

BK BK BK BR Transformer G 4P5 BU W BU

5P2 1P3

W

HF Triac BK1P6 BK

7103 2P2

HF Relay BU BU HF Filter N 4902 W Y Y

RR

5P6 Motor Capacitor

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Microwave Oven Plugged In—Time of Day Displayed

L Filter Fuse Electronic Control Filter N 20AMP L.V. 4P5 BU BK BK BK BR 5P2 Transformer 1P3 G W BU W

Cavity Thermostat

Door Open—Oven Cavity Light is On

Electronic Control Cavity

L.V. Thermostat N

BR 5P2 Transformer 1P3 G 4P5 BU W BU W

Fuse Filter 20AMP L Filter OR 3P2

BK BK BK CL Relay

4901 GY W

Primary 6P2 CL Interlock Switch Cavity Lamp

Cooktop Light on High

Electronic Control

L Fuse Cavity

Filter 20AMP L.V. Thermostat N

BK BK BK BR 5P2 Transformer G 4P5 BU W BU W 1P3

Filter

W

HL Relay 1P2 Y 5P5 R HL 4911 Hood Lamp Cooktop Light on Low (Night Light)

Electronic Control

L Fuse Cavity 20AMP Filter L.V. Thermostat N

BK BK BK BR Transformer G 4P5 BU W BU W 5P2 1P3

Filter

W

HL Relay Diode 4912 6106 1P2 Y 5P5 R

HL Hood Lamp

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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: 2. Release the OFF/CANCEL button and close the door. All 1. Press and hold the OFF/CANCEL button while opening VFD segments will be lit to indicate the test mode has been entered. the door. While still holding the OFF/CANCEL button, unplug the microwave oven for 2 seconds, then plug it NOTE: If the OFF/CANCEL button is pressed during this back in. diagnostic routine, you will exit the test mode.

Key Tables for Test Mode

Key Name Function Display Buzzer Key Name Function Display Buzzer Start – Key 1 1 beep 0 Key 32 1 beep Light Hi/Lo/Off – Key 3 1 beep 1 – Key 33 1 beep Hood Exhaust Key 34 1 beep Fan (HF) – Key 4 1 beep 2 Cavity Light Key 35 1 beep Hi/Med/Lo/Off On—Relay Key 36 1 beep Turntable On/Off – Key 5 1 beep 3 Key 37 1 beep Clock 4901 Key 38 1 beep Timer Set/Off – Key 6 1 beep 4 Key 39 1 beep Add 30 Sec 5 Cooktop Light Key 40 1 beep Cook Time – Key 7 1 beep 6 On (High)— Key 41 1 beep Cook Power Relay 4911 Warm Hold – Key 9 1 beep 7 – 1 beep Cook 8 Microwave Reheat – Key 10 1 beep Oven On for Defrost 9 10 Seconds— Frozen Entrée – Key 11 1 beep Relay 4903 Beverage Cancel/Off (to Popcorn – Key 12 1 beep lock hold, hold – Baked Potato for 3 seconds Pizza – Key 13 1 beep –

– Key 14 1 beep Cavity Light & Turntable – Key 15 1 beep On—Relay

– Key 16 1 beep 4901 &4906

– Key 17 1 beep –

– Key 18 1 beep Cooktop Light On (Night)— – Key 19 1 beep Relay 4912

HF On (High Speed)—

Relay 4902 & Triac 7102

Exit Test Mode

– Key 20 1 beep

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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

Display Likely Failure Condition Recommended Repair Procedure Flashing Power failure colon “:” Membrane switch 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. Microwave relay failure F6 1. Unplug microwave oven or disconnect power. 2. Replace membrane switch. 3. If problem persists, replace electronic control. 4. Plug in microwave oven or reconnect power.

1. Unplug microwave oven or disconnect power. 2. Check wiring to Relay 4903 for short circuits. 3. If wiring is OK, replace electronic control. 4. Plug in microwave oven or reconnect power.

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Component Tests

IMPORTANT:

s Unplug microwave oven or disconnect power. s Conduct a microwave energy test after performing any tests or repairs to the microwave oven. s Remove the lead wires from the related component before conducting any of the following tests. s Check that all wire leads are in the correct positions before operating the microwave oven. s Discharge the high-voltage capacitor and remove the lead wires from the primary winding of the high-voltage s Grasp wire connectors when removing the wire leads transformer before conducting any of the following from microwave oven parts. tests. s All testing must be done with an ohmmeter having a s All operational checks using microwave energy must be sensitivity of 20,000 ohms per volt DC or greater, and done with the microwave oven loaded with a minimum powered by at least a 9-volt battery. of 8 oz (250 mL) of water in a microwave safe container.

Components Test/Results

H.V. Transformer 1. Unplug microwave oven or disconnect power.

Filament 2. Remove wire leads. (orange/red wires) 3. Measure resistance (ohmmeter scale: Rx1): Primary (white wire) s Primary winding: Less than 0.5 ohm (approximate) s Secondary winding: 80 ohms (approximate) Primary (brown wire) s Filament winding: 0 ohms

Secondary 4. Measure resistance (ohmmeter scale: Rx1k): (white wire – s Primary winding to grounding: Normal: Infinite ground to transformer case) s Filament winding to grounding: Normal: Infinite

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

NOTE: Some inexpensive meters may indicate infinite resistance in both directions. 1. Unplug microwave oven or disconnect power. 2. Measure resistance (ohmmeter scale: Rx1k):

s Forward: Normal: Continuity; Abnormal: Infinite s Reverse: Normal: Infinite; Abnormal: Continuity

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Components Test/Results Turntable Motor Hood Exhaust Fan Motor 1. Unplug microwave oven or disconnect power. 2. Remove wire leads. Hood Thermistor 3. Measure resistance (ohmmeter scale: Rx1k):

s Turntable Motor—Normal: 2.7k-3.8k ohms (approximate); 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: 100-200 ohms (approximate); Blue (BU) and Black (BK) wires: 40-100 ohms (approximate); Abnormal: Infinite

s Low Speed—Normal: Red (R) and Blue (BU) wires: 100-200 ohms (approximate); Blue (BU) and White (W) wires: 80-150 ohms (approximate); Abnormal: Infinite

1. If “NTC SHORT, CALL FOR SERVICE” or “NTC OPEN, CALL FOR SERVICE” scrolls on display, unplug microwave oven or disconnect power.

2. Replace hood thermistor.

P5 3551

AC Line Filter 1. Unplug microwave oven or disconnect power.

U1 U2 2. Remove wire leads.

L3 1U 2 3. Measure resistance (ohmmeter scale: Rx1): s Normal: U1-L3 (coil): Less than 1 ohm; U2-N4 (coil): Less than 1 ohm; L N N4 L3-N4 (resistor): 550k-800k ohms s Abnormal: Infinite 3 4

Thermostats NOTE: Refer to “Parts Layout” for opening and closing temperatures.

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

s Cavity and Magnetron Thermostats—Normal: Continuity; Abnormal: Infinite

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Notes

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8205886 / 4619-651-98971 12/05 FOR SERVICE TECHNICIAN’S USE ONLY