Tech Sheet Do not discard

8206217 / 4619-651-98872 FOR SERVICE TECHNICIAN’S USE ONLY

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

MICROWAVE ENERGYa. Do not operate or allow the oven to be operated with

the door open.b. Make the following safety checks on all ovens to be

serviced before activating the magnetron or other microwave source, and make repairs as necessary:1. Interlock Operation2. Proper Door Closing3. Seal and Sealing Surfaces (Arcing, Wear and Other

Damage)4. Damage to or Loosening of Hinges and Latches5. 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.

d. Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in service manual before the oven is released to the owner.

e. A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner.

f. Do not attempt to operate the oven if the door glass is broken.

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.

2

WIRING DIAGRAMSSchematic Diagram

Sym

bol N

otes

BK

: Bla

ckB

U: B

lue

R: R

ed

W: W

hite

G: G

reen

Y: Y

ello

w

1 B

RW

ire C

olor

- B

row

nW

ire N

o. -

1

Con

ditio

n: D

oor

Ope

n.

Mag

netr

on

Fus

e

5 W

4 B

R

27 BU

26B

U

Sec

onda

ryIn

terlo

ckS

witc

h

Relay Board

Prim

ary

Inte

rlock

Sw

itch

CF

TT

Cav

ity L

amp

Coo

ling

Fan

Mot

or

Turn

tabl

e M

otor

Hoo

d E

xhau

stFa

n M

otor

P21

/P31

/P32

/P33

/P34

/P35

/P51

/P52

/P53

/P54

/P55

/P56

/P57

/P58

/P61

/P62

/P63

/P64

/P65

/P66

/P67

/P68

/P71

/P72

/P73

/P

74/C

N70

1/C

N70

2/C

N70

3: W

ire to

PC

B C

onne

ctor

s

Hoo

d La

mp

(Coo

ktop

Lam

p)H

LCL

46 R

47 R

BR

: Bro

wn

OR

: Ora

nge

TR

: Tra

nspa

rent

CN

702

CN

701

1 B

R

20 A

mp

P85

/P86

/P87

/P88

/P89

/P90

: Wire

to R

elay

Con

nect

ors

45 Y/G

GY

: Gra

y

1

CN

703

E70

1

Inve

rter

Mon

itor

Inte

rlock

Sw

itch

25R

L N

G W120V

/125

V,6

0Hz

W /

3C

Rib

bon

Cab

le A

wg

/ 3 C

ore

12

12

12

Start Quartz Tube

Halogen Grill Element

Quartz Grill Heater

The

rmos

tat

24 G

7 B

R

MW

Rel

ay49

03H

eate

rR

elay

4904

Gril

lR

elay

4914

Sta

rtR

elay

4924

12

TT

TTR

elay

4906

1P

53

CF

Rel

ay49

01

FCFA

Rel

ay49

07

P52

NF

CH

Rel

ay49

05

CF

FC

55 W

5P81

50 W

6P81

FC Ring Heater

GN

D

R

HF

WBK

Mot

orC

apac

itor

Hoo

d E

xhau

stFa

n M

otor

FC

TH

FC

TH

FC

(F

orce

d C

onve

ctio

n)T

herm

oact

uato

r

FC

FC

(F

orce

d C

onve

ctio

n)Fa

n M

otor

R

HF

BK

CF

FCFA

500m

AF

use

L

P74

1

FCThermistor

2 B

R

39 BU

35 BR

56 W

36 R

42 GY

8 R

41 R

40 GY

15 BU

37 R

33 BK

49 B

K

12

1

Mag

netr

on T

herm

isto

r

HF

Tria

c71

90

Y

TR

TR

1P81

Y

1

HL

HL

32W

31W

2P81

P58

51 W

52 W

W

FC

1P84

2P84

1

6 R

The

rmos

tat

Gril

l

12 BK

1P8234 BU

4P81

2P82

10uF

4121

3P82

3P81

20 BU

21 BK

11 B

U

16 R

10 W

9 R

14 BK

17 B

K

13 W

P51

P57 P56

P67

P66

1 BKRW

P68

Relay Control Board

Hum

idity

Sen

sor

1P

73

Hoo

d/Li

ght

Sw

itch

P65

P61

1CN701

Inve

rter

1P

54

103

1 P55

3

P71

P21

CL

1

P63

The

rmos

tat

Bas

e

38 R

1

P62

Doo

rN

FS

Inve

rter

500m

A

Fus

e

4170

Relay 4924-1

19 W

53 BK

P62

-2/N

FS

2P83

1P83

22 GY

43 B

U

54 BK

3 BR

L1 N1

P34

P31

Coi

lR

Cy

Cy

Cx

P32

P33

AC

Lin

e F

ilter

Cx

VD

RV

DR

P35

BK

MWRelayfeedback

P85

P90

1 2

P87

P88

P89

TT

2P91

1P91

P86

P81

/P82

/P83

/P84

: Wire

to W

ire C

onne

ctor

s

23 O

R

28 B

U

18 B

U

Cav

ityTh

erm

osta

t

P64

UIB

GY

/5C

P2

P3

LCD

W /

3 C

BK

/ R

/ 10

C

Y /

3C

Wav

egui

deTh

erm

osta

t

8P81

58 R

29 BU

VDR

57 W

7P81

DW

G N

O.

MU

-082

UIB Thermistor

W R BK

BK

W

R/W

R R

3

Parts Layout(not to scale)

A. Halogen grill element B. Start quartz tube C. Quartz grill heaterD. Grill thermostat—opens at 293ºF

(145ºC), closes at 158ºF (70ºC) E. Waveguide thermostat—opens at 257ºF

(125ºC), closes at -63.4ºF (-53ºC) F. AC line filter G. Relay board H. Magnetron thermistor I. Magnetron J. Secondary interlock switch K. FC thermoactuator L. Ferrite ring

M. Inverter

N. Cooling fan motor O. Motor capacitor P. Monitor interlock switch Q. Primary interlock switch R. Relay control board S. Line fuse (20 amp) T. Fuse holder U. Hood (cooktop) lamps V. Hood exhaust fan motor

W. Base thermostat—closes at 140ºF (60ºC), opens at 104ºF (40ºC)

X. Turntable motor Y. Touch panel (back and front views)Z. Cavity lamp

AA. Hood/light switch BB. FC motor CC. FC thermostat—opens at 329ºF

(165ºC), closes at 257ºF (125ºC) DD. FC ring heater EE. FC thermistor FF. Humidity sensor

GG. Cavity thermostat—opens at 329ºF (165ºC), closes at -22ºF (-30ºC)

HH. Door control assembly (back view) (includes the touch panel only)

II. UIB (user interface board)JJ. LCD module

Primary, Secondary, and Monitor Interlock Switch Checkout Procedure

Switch Check By Door Open Door Closed

Primary Interlock

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

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 Interlock

1. Unplug microwave oven or disconnect power.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 Interlock

1. Unplug microwave oven or disconnect power.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

AB

CD

EF

GHIJK

L

M

NO

PQRST

UVWXY

AA

BB

CC

DDEE

ZU

FFGG

HH

II JJ

Y

4

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

TROUBLESHOOTINGDo not continue with the diagnostics of appliance if the household fuse is blown, a circuit breaker is tripped or if there is less than 120-volt power supply at the wall outlet.Complete the following steps before checking microwave oven circuitry:1. Unplug microwave oven or disconnect power.2. Check for loose wiring or incorrect wiring within

microwave oven.

3. Disconnect white wire from power transformer and discharge high-voltage capacitor.

4. All testing must be done with an ohmmeter having a sensitivity of 20,000 ohms per volt DC or greater, and powered by at least a 9-volt battery.

5. All operational checks using microwave energy must be done with the microwave oven loaded with a minimum of 8 oz (250 mL) of water in a microwave-safe container.

Inverter and Magnetron Circuit

Halogen Grill Heater Circuit

Quartz Grill Heater Circuit

MonitorInterlockSwitch

PrimaryInterlockSwitch

SecondaryInterlockSwitch

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

L N

MonitorInterlockSwitch

PrimaryInterlockSwitch

SecondaryInterlockSwitch

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

Filter2

49031

BU

CavityThermostatPrimary

InterlockSwitch

MW RelayBUBR

P56

P66CN702

P65

CN

701

CN

703Inverter

Magnetron

12

3

32

1

R

R Relay Control Board

Relay Board

BR

10

SecondaryInterlockSwitch

BK BU

RibbonCable

L

BK BRN

WFilter

RibbonCable

Fuse20 Amp

WaveguideThermostat

BU

BU

CavityThermostat

Primary InterlockSwitch

BUBR

Fuse20 Amp

W

Secondary Interlock

Switch

Halogen GrillElement

Grill Relay4914

2 1W WR W

Grill ThermostatL

BK BRN

WFilterFilter

Relay Board

BU

WaveguideThermostat

LBK Filter BR

Fuse20 Amp

Primary InterlockSwitch

GrillThermostat

W R W BUQuartz Grill Element

Heater Relay4904

Relay Board

2 1BU BU W

Secondary InterlockSwitch

BU BU

CavityThermostat

Filter WN

BU

WaveguideThermostat

BR

5

Start Quartz Tube Circuit

Forced Convection Circuit

Hood Exhaust Fan On (Variable Speed)

Cooling Fan Motor Circuit

BU

CavityThermostat

BU

Secondary InterlockSwitch

2 1

W

L NWFilterHalogen Grill Element

BU

BK

BK Filter BR

Fuse20 Amp

Primary InterlockSwitch

GrillThermostat

Start Quartz Tube

BR W R W

BK

BK

Relay Board

Start Relay4924

BU

WaveguideThermostat

Relay Board G

R3P53

BR BR

P52

WFC Ring Heater

P51

2 1FCH Relay

4905

RRR Cavity

Thermostat

4P53

F CFCFA Relay

4907FCTH

PrimaryInterlock

Switch

BR R

BR

R GY

GY

BU BU

FCThermostat

NW

L

BKFilter Filter

Fuse20 Amp

WaveThermostat

4P545P81

Fuse

500mA

Inverter

4170BR

HF

2P82

3P82

1P821P54

3P81

HF Triac

7190

BKBK

MotorCapacitor

W

RR

BK

W

P52P51 BR

W

Fuse20 Amp

BR BR

GRelay Board

R BUN

WL

BK

Filter

Filter CavityThermostat

R

R8P81

7P81

BU

WaveguideThermostat

CF2P53

1P83

CF Relay4901

Relay Board

BU

BU

GBR BRP52P51

CavityThermostat

BR BU BUN

WL

BKFilterFilter

Fuse20 Amp

WaveguideThermostat

4P54BR

R

2P835P81

6

Turntable Motor Circuit

Door Open—Oven Cavity Light is On

Cooktop Light On (Variable Light)

Hood Exhaust Fan On Auto

4P54W

TT

1P53

Relay Board

BR

W

5P81

R

GBR BRP52P51

CavityThermostat

BR BU BUN

WL

BKFilterFilter

6P81

Fuse20 Amp

TT Relay4906

WaveguideThermostat

R

LN

Fuse20 Amp BR

WBK BR B RP51 P52

2P55

Fuse500mA

Inverter

4170

4121

Fuse500mA

3P55

P611 2 3

BU BUG

Relay ControlBoard

Relay Board

P63

OR

1P62

12

FilterFilter

PrimaryInterlock

Switch

CavityThermostat

CavityLamp

1P55

R

WaveguideThermostat

RR

L NFuse

20 AmpWBK BR BU BUG

P582

1 W

W

W

TR

Y

W

TR

Y

HL HL

1P84

2P84

2P81

1P81

Filter Filter

CavityThermostat

R

WaveguideThermostatBR

P51 P52

2P55

Fuse500mA

Inverter

4170

4121

Fuse500mA

3P55

P611 2 3

Relay ControlBoard

Relay Board

P63

OR

1P62

12

PrimaryInterlock

Switch

CavityLamp

1P55

BR

R

R

L

N

Fuse20 Amp

BR

W

BK BR BRP51

P52

BU BUG

Relay Board

4 P54

HF2P82

3P82

W

RBR W W

BKBKBKBU

1P82

5P81

4P81

Filter

BaseThermostat

MotorCapacitor

Filter

CavityThermostat

7P81 8P81

R

WaveguideThermostat

R

R

R

7

Touch Panel

Touch Panel and Relay Control Board Tests

To access the test mode:1. Unplug microwave oven or disconnect power.2. Open the microwave oven door.3. Press and hold OFF/CANCEL.

4. Plug in microwave oven or reconnect power.5. Release OFF/CANCEL and close microwave oven door.NOTE: If the OFF/CANCEL key is pressed during this diagnostic routine, you will exit the test mode.

Test Mode Table

Troubleshooting Circuit Test Chart

Cooking Mode Magnetron

Convection Element

Grill Elements Cooling Fan

Convection Fan

Hood Exhaust Fan

Microwave only

On On

Convection On On On On

Grill On On On

Microwave and Grill Combination

On On On On

Microwave and Convection Combination

On* On* On On On

*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.

Screen Display Display Explanation

UIB SW ver Version number of UIB (user interface board) software

PB SW Ver Flash Version number of power board (relay control board) software

FC thermistor (ºC) The temperature (ºC) measured by FC (forced convection) thermistor—maximum 250ºC

UIB thermistor (ºC) The temperature (ºC) measured by UIB (user interface board) thermistor—ranges about 5ºC above room temperature, if oven has not been used recently

Magnetron thermistor (ºC) The temperature (ºC) measured by magnetron thermistor—maximum 125ºC

HUM PWM Humidity level inside unit—ranges between 8,000 and 9,500, depending on humidity level in oven cavity

Screen Display Display Explanation

Hood Key Hood key number

Touch panel Touch panel error

EEPROM Version number of PB (relay control board) EEPROM (Electrically Erasable Programmable Read-Only Memory)

MW reply error MW relay error

Smps FB error Smps feedback error

Hum sensor error Humidity sensor error

Cavity thermistor error Cavity thermistor error

Magnetron thermistor error Magnetron thermistor error

EEPROM error Power board (relay control board) error

8

Microwave Oven Power Output Test1. Place 8 oz (250 mL) of lukewarm water in the center of the

microwave oven.2. Operate on HIGH power level for 2 minutes. Water

should be hot.

NOTE: If the water takes longer than 2 minutes to heat, this may indicate either the operating voltage is lower than 110 volts or there is a problem with the microwave oven.

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 defective

1. Unplug microwave oven or disconnect power.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.

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. Plug in microwave oven or reconnect power.5. If problem persists, unplug microwave oven or disconnect power.6. Replace relay control board.7. Plug in microwave oven or reconnect power.

F3.T1 UIB (user interface board) thermistor

1. Unplug microwave oven or disconnect power.2. Check the connections from the UIB to the relay control board.3. Plug in microwave oven or reconnect power.4. If problem persists, unplug microwave oven or disconnect power.5. Replace relay control board.6. Plug in microwave oven or reconnect power.7. If problem persists, unplug microwave oven or disconnect power.8. Replace the UIB.9. 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. Plug in microwave oven or reconnect power.5. If problem persists, unplug microwave oven or disconnect power.6. Replace relay control board.7. 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. Plug in microwave oven or reconnect power.5. If problem persists, unplug microwave oven or disconnect power.6. Replace relay control board.7. Plug in microwave oven or reconnect power.

9

Component Tests

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. Plug in microwave oven or reconnect power.5. If problem persists, unplug microwave oven or disconnect power.6. Replace relay board.7. Plug in microwave oven or reconnect power.8. If problem persists, unplug microwave oven or disconnect power.9. Replace relay control board.10. Plug in microwave oven or reconnect power.

F7 Power to magnetron interrupted

1. Unplug microwave oven or disconnect power.2. After 40 seconds, check to see whether this solves the problem. 3. Unplug microwave oven or disconnect power.4. Check cooling fan operation5. Check the magnetron.6. Check P65 connection on the relay control board.7. Check the P56/P66 connection between relay board and relay control

board.8. Check wiring to the 1100W inverter and control system. See “Checking

Inverters.”9. Check operation of all interlock switches. 10. Plug in microwave oven or reconnect power.11. Check voltage at 4903-1 on relay board. If it is 120, unplug microwave

oven or disconnect power.12. Replace inverter. 13. Plug in microwave oven or reconnect power.14. If problem persists, unplug microwave oven or disconnect power.15. Replace relay control board.16. Plug in microwave oven or reconnect power.

F9 Relay control board communications error

1. Unplug microwave oven or disconnect power.2. Check the communications cable from P66 to P56 between relay control

board and relay board.3. Plug in microwave oven or reconnect power.4. If problem persists, unplug microwave oven or disconnect power.5. Replace the relay board and relay control board.6. 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.3. Plug in microwave oven or reconnect power.4. If problem persists, unplug microwave oven or disconnect power.5. Replace the door control assembly.6. Plug in microwave oven or reconnect power.

IMPORTANT:

■ Unplug microwave oven or disconnect power.■ Remove the lead wires from the related component

before conducting any of the following tests.■ Discharge the high-voltage capacitor and remove the

lead wires from the primary winding of the high-voltage transformer before conducting any of the following tests.

■ All operational checks using microwave energy must be done with the microwave oven loaded with a minimum of 8 oz (250 mL) of water in a microwave safe container.

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

■ Check that all wire leads are in the correct position before operating the microwave oven.

■ Grasp wire connectors when removing the wire leads from microwave oven parts.

■ All testing must be done with an ohmmeter having a sensitivity of 20,000 ohms per volt DC or greater, and powered by at least a 9-volt battery.

Failure Codes Indications

Display Likely Failure Condition Recommended Repair Procedure

10

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:

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

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

■ Normal: 41 +/- 5 ohms■ Abnormal: Infinite

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

■ Normal: 21.5 +/- 5 ohms■ Abnormal: Infinite

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

■ Normal: 2.2k +/- 0.5k ohms (approximate)■ Abnormal: Infinite

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

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

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

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

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

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

■ Normal: 9 +/- 3 ohms■ Abnormal: Infinite

Humidity Sensor 1. Unplug microwave oven or disconnect power.2. Remove the 3-pin connector from Relay Control Board.3. Measure resistance across pins 1 and 3, and across pins 2 and 3:

■ Normal: 2.8k ohms (approximate) at 77º +/- 10ºF (25º +/- 10ºC)■ Abnormal: Infinite

1 2 3BK

W

R

P34

P31

P33

P32

123

Y/G

BKRW

11

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

■ FC, Grill, Cavity and Waveguide Thermostats: Normal: Continuity; Abnormal: Infinite

■ Base Thermostat: Normal: Infinite; Abnormal: Continuity

Halogen Grill Element1000W, 120V (inside cavity)

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

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

Start Quartz Tube600W, 60V (not visible to user)

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

■ Normal: 6 +/- 3 ohms ■ Abnormal: Infinite

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

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

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

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

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

■ Normal: 10k +/- 5% ohms at 77ºF (25ºC)■ Abnormal: Infinite

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

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

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

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

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

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

Components Tests/Results

FC / Grill / Cavity /Waveguide Thermostat

BaseThermostat

Checking Inverters

Measure Oven Input Current

Connect an ammeter (Valhalla Scientific 2101 or equivalent recommended) to measure the input current of microwave oven when the power level is set to Level 10 at the touch panel.

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

If less than 0.5A:There is no input to the 1100W inverter. Check the following:1. Unplug microwave oven or disconnect power.2. No AC voltage supply. Check relay control board and

wiring.3. 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 any adjustments to the board.

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.

Relay Control Board NOTE: Do not try to repair or make adjustments to the relay control board.1. Unplug microwave oven or disconnect power.2. Check wiring to relay control board.3. Visually inspect P61, P62, P63, P64, P65, P66, P67, P68, P71, P73 and P74 to see

whether there are signs of overheating or any signs of failure due to loose wires, bad crimping, etc.

Hood / Light Switch NOTE: Do not try to repair or make adjustments to the hood/light switch.1. Unplug microwave oven or disconnect power.2. Check wiring to hood/light switch.3. Visually inspect P21 to see whether there are signs of overheating or any signs of

failure due to loose wires, bad crimping, etc.

Relay Board NOTE: Do not try to repair or make adjustments to the relay board.1. Unplug microwave oven or disconnect power.2. Check wiring to relay board.3. Visually inspect P51, P52, P53, P54, P55, P56 and P57 to see whether there are

signs of overheating or any signs of failure due to loose wires, bad crimping, etc.

Components Tests/Results3

12

1

1P

62

1P

61

61

52

P6

31

P6

6

P6

41

P6

8

70

01

46

25

P6

51

P6

71

P7

11

P7

31

P7

41

P21

P224501

45024503

49

14

49

04

49

24

49

05

P52

P51

31

1049

06

49

01

49

07

1P53

3191

49314932

1P54

4903

4121

P54

1

P56

P57

1

4170

P581

5174

5170

15A

Amps

A. CN702B. Heat sinkC. E701D. High-voltage output

to magnetron

E. CN703F. Control signal in/outG. CN701H. 120V AC

B

G

A

C

D

EF

H

8206217 / 4619-651-988721/06

FOR SERVICE TECHNICIAN’S USE ONLY