tech-sheet-8205285
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.

8205285 / 4619-651-98871 FOR SERVICE TECHNICIAN’S USE ONLY

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120V/125V,60Hz Fuse Primary 23 OR Interlock L BK AC Line Filter L1 1 BR 2 BR 4 BR Switch 6 R

P32 Cy VDR P33 20 Amp 5 W 2P81 52 W 2P84 GND Cx R Coil 28 BU Base 1P91 55 W 43 BU 32 W TR TR Cx 50 W 5P81

G Monitor Thermostat TT 6P81 2P83 41 R FC 8 R 31 W Y HL HL 4P81 CF Cy Interlock 3P81

W N1 Switch 49 BU 2P91 1P83 Grill FC 1P81 51 W Y N P31 P34 42 GY Door Relay 4924 40 GY FCTH Thermostat Thermostat 1P84 VDR P62 NFS 1 39 BU P35 R 1 P63 36 R 10 W 7 BR 9 R 1 CL R P58 VDR 35 BR Softstart Quartz Tube P89 11 BU Quartz Grill Heater P86 WIRING DIAGRAMS

33 BK 15 BU FC Ring Heater P87 Schematic Diagram Halogen Grill Element P88 UIB Thermistor P2 GY/5C W / 3C P54 1 P53 1 12 BK Relay Board 45 Y/G P57 13 W UIB P64 Relay Control Board P67 3 TT CF FCFA 47 R 46 R LCD P3 1 CN701 FC W 1 HF Thermistor Triac Inverter R P71 P66 BK / R / 10 C P56 7190 14 BK 16 R 1 10 MWRelay CN702 feedback BK 1 2 2 2 2 2 2 P90 BK P74 1 CN703 Magnetron Thermistor TT CF FCFA P85 56 W Relay Relay E701 P65 53 BK 4906 4901 3 BR 34 BU N 54 BU Y / 3 C P52 Relay P61 3 Fuse Fuse 4907 1 1 1 1 1 MW 500mA Relay 1 1 P55 4121 500mA L Softstart Grill Heater FCH 4903 CN701 4170 Relay Relay Relay Relay 27 BU 4924 4914 4904 4905 17 BK Inverter P51 20 BU 21 BK Inverter P68 P73 22 GY

Cavity 1 1 57 W 7P81 37 R 24 G Thermostat 58 R 8P81 3P82 R 38 R 2P82 W P62-2/NFS 1P82 BK 19 W R/W 18 BU W

BK R W 29 BU Waveguide Humidity P21 10uF/400V Secondary Thermostat Sensor Hood/Light Interlock Hood Exhaust Motor Switch Switch HF Fan Motor Capacitor Magnetron

26BU 25R

Condition: Door Open. BK Hood Exhaust P21/P31/P32/P33/P34/P35/P51/P52/P53/P54/P55/P56/P57 Symbol Notes Fan Motor /P58/P61/P62/P63/P64/P65/P66/P67/P68/P71/P72/P73/ W HF P74/CN701/CN702/CN703: Wire to PCB Connectors P81/P82/P83/P84: Wire to Wire Connectors CL Cavity Lamp R P85/P86/P87/P88/P89/P90: Wire to Relay Connectors DWG NO. MU-082

Hood Lamp CF Cooling Fan Motor 1 BR (Cooktop Lamp) W / 3C HL FC FC (Forced Convection) BK: Black W: White BR: Brown Wire Color – Brown Fan Motor OR: Orange Wire No. – 1 BU: Blue G: Green GY: Gray Ribbon Cable Awg / 3 Core

TT Turntable Motor FCTH FC (Forced Convection) R: Red Y : Yellow Thermoactuator TR: Transparent

Parts Layout

(not to scale)

GG A B HH FF CD EE DD

EF

CC

G

H

BB I

J

K

L

Y M

II JJ AA N ZUY X W PO VU T SR Q

A. Halogen grill element N. Cooling fan motor AA. Hood/light switch B. Softstart quartz tube O. Motor capacitor BB. FC motor C. Quartz grill heater P. Monitor interlock switch CC. FC thermostat—opens at 329ºF D. Grill thermostat—opens at 293ºF Q. Primary interlock switch R. Relay control board (165ºC), closes at 257ºF (125ºC) (145ºC), closes at 158ºF (70ºC) S. Line fuse (20 amp) DD. FC ring heater E. Waveguide thermostat—opens at 257ºF T. Fuse holder EE. FC thermistor U. Hood (cooktop) lamps FF. Humidity sensor (125ºC), closes at -63.4ºF (-53ºC) V. Hood exhaust fan motor GG. Cavity thermostat—opens at 329ºF F. AC line filter W. Base thermostat—closes at 140ºF G. Relay board (165ºC), closes at -22ºF (-30ºC) H. Magnetron thermistor (60ºC), opens at 104ºF (40ºC) HH. Door control assembly (back view) I. Magnetron X. Turntable motor J. Secondary interlock switch Y. Touch panel board (back and front (includes the touch panel board K. FC thermoactuator only) L. Ferrite ring views) II. UIB (user interface board) M. Inverter Z. Cavity lamp JJ. LCD module

Primary, Secondary, and Monitor Interlock Switch Checkout Procedure

Switch Check By 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 (brown wires) 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 (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 wire) 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 (blue wire) to the normally closed terminal (white/red wires).

(+) Continuity (-) No Continuity

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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) (NC) (NO) (NO) (NC) (NO)

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

TROUBLESHOOTING

Do not continue with the diagnostics of appliance if the 2. All testing must be done with an ohmmeter having a household fuse is blown, a circuit breaker is tripped or if there sensitivity of 20,000 ohms per volt DC or greater, and is less than 120-volt power supply at the wall outlet. powered by at least a 9-volt battery.

Complete the following steps before checking microwave 3. All operational checks using microwave energy must be oven circuitry: done with the microwave oven loaded with a minimum of 8 oz (250 mL) of water in a microwave-safe container. 1. Unplug microwave oven or disconnect power.

Inverter and Magnetron Circuit

L Relay Board Waveguide BK Filter MW Relay Thermostat BU Filter N W BR BR BR 2 4903 1 BK BU BU BU

Fuse Secondary Cavity 20 Amp Primary Ribbon P56 Interlock Thermostat Interlock Cable 10 Switch Magnetron Switch P66 Ribbon CN702 R Cable R Inverter Relay Control Board CN703

CN701 1 23 3 21

P65

Halogen Grill Heater Circuit

Grill Thermostat Secondary

L Grill Relay Interlock Cavity N 4914 Switch W BK Filter BR Thermostat Filter W Relay Board BR WR W2 1W BU BU BU

Fuse Primary Interlock Halogen Grill Waveguide 20 Amp Switch Element Thermostat

Quartz Grill Heater Circuit

Grill

Fuse Thermostat Heater Relay Secondary Interlock Cavity Thermostat L 20 Amp Quartz Grill Element 4904 Switch N BK BR Filter W Filter BR WR W BU BU BU W BU BU BU 2 1

Primary Interlock Relay Board Waveguide Thermostat

Switch

Softstart Quartz Tube Circuit

Fuse Grill Secondary Interlock Cavity 20 Amp Thermostat BR L Halogen Grill Element Switch Thermostat N BK W Filter BR WR BU W BU BU BU Filter W

BK Softstart Relay Waveguide

Primary Interlock BK 2 4924 BK Thermostat Switch 1

Softstart Quartz Tube Relay Board

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Forced Convection Circuit

R GY 3P53

FC FCTH FCFA Relay 4907 R GY 4P53 Relay Board Fuse BR P52 G 20 Amp P51 FCH Relay 4905 L BR BR W R BR FC Ring Heater BU BU Filter N Filter Primary R R2 W Interlock 1 R Wave BK Switch FC Cavity

Thermostat Thermostat Thermostat

Hood Exhaust Fan On (Variable Speed)

Fuse

W 2P82 W 500mA BR 4P54 4170 HF W 7P81 5P81 BK R Inverter R RR Motor HF Tr i a c 3P82 8P81 Capacitor

BK BK 1P54 3P81 1P82 7190

Waveguide

Fuse Thermostat Filter N 20 Amp W L BR P51 P52 G R BU BU

Filter BR BR Relay Board Cavity

BK Thermostat

Cooling Fan Motor Circuit

1P83 BU

CF BU 2P53 CF Relay 4P54 4901 Fuse BR L 20 Amp 2P83 5P81 Waveguide Filter BR BR Thermostat BU Filter N BK P52 G R W BR P51 BU Relay Board Cavity

Thermostat

Turntable Motor Circuit

L Fuse W R TT Relay Cavity Filter 20 Amp 4906 TT 1P53 Thermostat Filter N BK W Relay Board W BR BR BR 6P81 P52 G R BU BU

5P81 BR 4P54 P51

Waveguide

Thermostat

Door Open—Oven Cavity Light is On

L Fuse BR Relay Board Waveguide BK 20 Amp BR Filter Fuse Thermostat BU Filter N BR Primary 4170500mA W Interlock P51 G R BU P52 Switch Fuse Inverter 500mA Cavity Thermostat 4121

1P55 2P55 3P55

OR

1P62 12 3 12 Cavity P61 P63 Lamp

Relay Control Board

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Cooktop Light On (Variable Light)

Relay Board

L Fuse BR Fuse Waveguide Cavity BK 20 Amp 500mA Thermostat Filter 4170 Thermostat Filter N P51 Fuse Inverter BU W BR BR 500mA GR BU P52

Primary W 2P84 TR Interlock W 2P81 TR Switch 4121 21 P58 W Y HL HL

1P55 2P55 3P55 1P81 W Y

OR

12 3 1P84 P61 1P62 12 Cavity Relay Control P63 Lamp Board

Hood Exhaust Fan On Auto

Motor

L Fuse 7P81 W Capacitor BK 8P81 20 Amp RR Filter WR W BR BR BR BR P51 4 P54 P52 5P81 2P82 R Relay Board HF

BU BU BU BK 3P82 4P81 Base 1P82 Thermostat Filter N R BU W G BU

Waveguide Cavity Thermostat Thermostat

Troubleshooting Circuit Test Chart

Convection Hood Exhaust Cooking Mode Magnetron Element Grill Elements Cooling Fan Convection Fan Fan

Microwave only On On

Convection On On On On

Grill On On On

Microwave and On On On On

Grill

Combination

Microwave and On* On* On On On

Convection

Combination

*Magnetron and convection elements turn on alternately, not simultaneously.

NOTE: After convection or grill elements are on, the cooling fan and hood exhaust fan may be on for up to 10 minutes for cooling.

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Touch Panel

Touch Panel and Relay Control Board Tests

To access the test mode: Screen Display Display Explanation 1. Unplug microwave oven or disconnect power. 2. Open the microwave oven door. HUM PWM Humidity level inside unit— 3. Press and hold OFF/CANCEL. ranges between 8,000 and 4. Plug in microwave oven or reconnect power. 9,500, depending on humidity 5. Release OFF/CANCEL and close microwave oven door. level in oven cavity NOTE: If the OFF/CANCEL key is pressed during this diagnostic routine, you will exit the test mode.

Test Mode Table Hood Key Hood key number

Screen Display Display Explanation Touch panel board Touch panel error

UIB SW ver Version number of UIB (user EEPROM Version number of PB (relay interface board) software control board) EEPROM (Electrically Erasable PB SW Ver Flash Version number of power board Programmable Read-Only (relay control board) software Memory)

FC thermistor (ºC) The temperature (ºC) measured MW reply error MW relay error by FC (forced convection) thermistor—maximum 250ºC Smps FB error Power board (relay control board) error

UIB thermistor (ºC) The temperature (ºC) measured Hum sensor error Humidity sensor error by UIB (user interface board) thermistor—ranges +/- 5ºC Cavity thermistor error Cavity thermistor error above/below room temperature if oven has not been used Magnetron thermistor error Magnetron thermistor error recently

Magnetron thermistor (ºC) The temperature (ºC) measured EEPROM error Power board (relay control by magnetron thermistor— board) error maximum 125ºC

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.

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.

Failure Codes Indications

Display Likely Failure Condition Recommended Repair Procedure

F1.E1 Relay control board 1. Unplug microwave oven or disconnect power. defective 2. Replace the relay control board. 3. Plug in microwave oven or reconnect power.

F2.H1 Hood keys stuck 1. Unplug microwave oven or disconnect power. 2. Replace hood/light switch. 3. Plug in microwave oven or reconnect power.

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Failure Codes Indications

Display Likely Failure Condition Recommended Repair Procedure

F2.H2 Hood/light switch defective 1. Unplug microwave oven or disconnect power. 2. Replace hood/light switch. 3. Plug in microwave oven or reconnect power.

F2.Q1 Not reading keypad inputs 1. Unplug microwave oven or disconnect power. 2. Replace the user interface board (UIB). 3. Replace the door control assembly. 4. Plug in microwave oven or reconnect power.

F3.H1 Humidity sensor 1. Unplug microwave oven or disconnect power. 2. Check connection to relay control board. 3. Replace humidity sensor. 4. If problem persists, replace relay control board. 5. Plug in microwave oven or reconnect power.

F3.T1 UIB (user interface board) 1. Unplug microwave oven or disconnect power. thermistor 2. Check the connections from the UIB to the relay control board. 3. If problem persists, replace relay control board. 4. If the problem persists, replace the UIB. 5. Plug in microwave oven or reconnect power.

F3.T2 FC thermistor 1. Unplug microwave oven or disconnect power. 2. Check FC thermistor connection. 3. Replace the FC thermistor. 4. If problem persists, replace the relay control board. 5. Plug in microwave oven or reconnect power.

F3.T4 Magnetron thermistor 1. Unplug microwave oven or disconnect power. 2. Check magnetron thermistor connection. 3. Replace the magnetron thermistor. 4. If problem persists, replace the relay control board. 5. Plug in microwave oven or reconnect power.

F6 MW relay 1. Unplug microwave oven or disconnect power. 2. Check the cable from P85 to inverter. 3. Check to see if the relay (4903 on relay board) contact has welded closed. 4. If problem persists, replace relay board. 5. If there is still a problem, replace relay control board. 6. Plug in microwave oven or reconnect power.

F7 Power to magnetron 1. Unplug microwave oven or disconnect power.

interrupted 2. After 40 seconds, check to see whether this solves the problem.

3. Check cooling fan operation.

4. Check the magnetron.

5. Check P65 connection on the relay control board.

6. Check the P56 to P66 connection between relay board and relay control

board.

7. Check wiring to the 1100W inverter. See “Checking Inverters.”

8. Check operation of all interlock switches.

9. Check voltage at 4903-1 on relay board. If it is 120, replace inverter. After

replacing inverter, if there is no voltage, replace relay control board.

10. Plug in microwave oven or reconnect power.

F9 Relay control board 1. Unplug microwave oven or disconnect power.

communications error 2. Check the communications cable from P66 to P56 between relay control

board and relay board.

3. If problem persists, replace the relay board and relay control board.

4. Plug in microwave oven or reconnect power.

F9.Q Touch communication 1. Unplug microwave oven or disconnect power. 2. Check the communications cable from UIB to the touch panel board. 3. If problem persists, replace the door control assembly. 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 position 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 Tests/Results

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

s Filament terminals: Normal: Less than 1 ohm s Filament to chassis: Normal: Infinite

Cooling Fan Motor 1. Unplug microwave oven or disconnect power. FC Motor 2. Remove wire leads. 3. Measure resistance: Turntable Motor s Normal: 41 +/- 5 ohms Hood Exhaust Fan Motor s Abnormal: Infinite

W 1. Unplug microwave oven or disconnect power. 2. Remove wire leads. BK R 3. Measure resistance:

12 3 s Normal: 21.5 +/- 5 ohms s Abnormal: Infinite AC Line Filter 1. Unplug microwave oven or disconnect power. P34 P33 2. Remove wire leads. 3. Measure resistance: P31 P32 s Normal: 2.2k +/- 0.5k ohms (approximate) FC Ring Heater s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s Pin 1 (BK) and 2 (W): Normal: 17 +/- 5 ohms; Abnormal: Infinite s Pin 1 (BK) and 3 (R): Normal: 21 +/- 5 ohms; Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s P31 and P32, P33 and P34: Normal: Greater than or equal to 300k ohms; Abnormal: Less than or equal to 100k ohms

s P31 and P34, P32 and P33: Normal: 0 ohms; Abnormal: Greater than or equal to 100k ohms

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s Normal: 9 +/- 2 ohms s Abnormal: Infinite

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Components Tests/Results

Humidity Sensor 1. Unplug microwave oven or disconnect power. 2. Remove the 3-pin connector from Relay Control Board. 1 BK 3. Measure resistance across pins 1 and 3, and across pins 2 and 3: 2R 3W s Normal: 2.8k ohms (approximate) at 77º +/- 10ºF (25º +/- 10ºC) s Abnormal: Infinite Y/G

Thermostats NOTE: Refer to “Parts Layout” for opening and closing temperatures. FC / Grill / Cavity / 1. Unplug microwave oven or disconnect power. 2. Remove wire leads. Waveguide Thermostat 3. Measure continuity: Base s FC, Grill, Cavity and Waveguide Thermostats: Normal: Continuity; Abnormal: Thermostat Infinite

Halogen Grill Element s Base Thermostat: Normal: Infinite; Abnormal: Continuity 1000W, 120V (inside cavity) 1. Unplug microwave oven or disconnect power. Softstart Quartz Tube 2. Remove wire leads. 600W, 60V (not visible to user) 3. Measure continuity (ohmmeter scale: Rx1):

s Normal: 2 +/- 1 ohms s Abnormal: Infinite

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

s Normal: 6 +/- 2 ohms s Abnormal: Infinite

Quartz Grill Heater 1. Unplug microwave oven or disconnect power. FC Thermistor 2. Remove wire leads. 3. Measure resistance:

s Normal: 29 +/- 5 ohms s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s Normal: 230k +/- 20% ohm at 77ºF (25ºC) s Abnormal: Infinite

Magnetron Thermistor 1. Unplug microwave oven or disconnect power. Motor Capacitor 2. Remove wire leads. FC Thermoactuator 3. Measure resistance: Cavity / Hood Lamp s Normal: 10k +/- 5% ohms at 77ºF (25ºC) s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s Normal: Momentarily 0 ohms, then goes to infinite s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s Normal: 1.2k +/- 0.5k ohms s Abnormal: Infinite

1. Unplug microwave oven or disconnect power. 2. Remove wire leads. 3. Measure resistance:

s Normal: 1.5 +/- 0.5 ohms s Abnormal: Infinite

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Components Tests/Results

Relay Control Board NOTE: Do not try to repair or make adjustments to the relay control board. 1. Unplug microwave oven or disconnect power. 3121 1 P74 P73 P71 1 P67 2. Check wiring to relay control board. 1 P62 1 P61 3. Visually inspect P61, P62, P63, P64, P65, P66, P67, P68, P71, P73 and P74 to see 6152 P63 1 P66 whether there are signs of overheating or any signs of failure due to loose wires, bad 7001 1 P65 4625 crimping, etc. 1 P68 NOTE: Do not try to repair or make adjustments to the hood/light switch. 11 P64 1. Unplug microwave oven or disconnect power. 2. Check wiring to hood/light switch. Hood / Light Switch 3. Visually inspect P21 to see whether there are signs of overheating or any signs of

P21 failure due to loose wires, bad crimping, etc.

4501 P22 4502 4503

Relay Board NOTE: Do not try to repair or make adjustments to the relay board. 1. Unplug microwave oven or disconnect power. P57 4905 2. Check wiring to relay board. 4924 3. Visually inspect P51, P52, P53, P54, P55, P56 and P57 to see whether there are signs 1 P58 1 P56 4903 4904 49324931 4914 of overheating or any signs of failure due to loose wires, bad crimping, etc. 5174 5170 3191 P52

P53 1 P51 1 4907 4901 4170 P54 4906 P54 3110

4121 1

Checking Inverters

Measure Oven Input Current If more than 0.5A: The 1100W inverter is probably OK. Check the magnetron. 15A See Magnetron test in “Component Tests.”

Amps If less than 0.5A: There is no input to the 1100W inverter. Connect an ammeter (Valhalla Scientific 2101 or equivalent Check the following: recommended) to measure the input current of microwave s No AC voltage supply. Check relay control board and oven when the power level is set to Level 10 at the touch panel. wiring. s No control signal. Check relay control board and wiring. Check the 1100W Inverter NOTE: Do not try to repair the inverter board, nor try to make A B any adjustments to the board.

H C Check wiring to 1100W inverter: 1. Unplug microwave oven or disconnect power. 2. Visually inspect 4 connectors on the 1100W inverter

board, CN701, CN702, CN703, E701, to see whether there are signs of overheating or any signs of failure due to loose wires, bad crimping, etc.

G D

F E

A. CN702 E. CN703 B. Heat sink F. Control signal in/out C. E701 G. CN701 D. High-voltage output H. 120V AC

to magnetron

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8205285 / 4619-651-98871 8/05 FOR SERVICE TECHNICIAN’S USE ONLY