Panasonic NN­GS595A - 7.3 Inverter Circuit & Magnetron Troubleshooting

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SYMPTOM CAUSE CORRECTIONS
2. Nodisplayandnooperationat
all.
Fuseisblown.
Checkadjustmentofprimary,
secondarylatchswitchandshort
switchincludingdoor.
2. Defectiveprimarylatchswitch(NOTE1)
3. Defectiveshortswitch(NOTE1)
4. DefectiveInverterPowerSupply(U)
NOTE1:
Alloftheseswitchesmustbereplacedatthesametime.
CheckcontinuityofpowerrelayB(RY1)ʼscontacts(between1and2)andifithas
continuity,replacepowerrelayB(RY1)also.
3.
Ovendoesnotacceptkeyinput
(Program)
1. Keyinputisnotinpropersequence Refertooperationprocedure.
2.
Openorlooseconnectionofmembranekeypadto
DPC(Flatcable)
3. Shortedoropenmembranekeyboard
4. DefectiveDPC RefertoDPCtroubleshooting.
4.
Fanmotorturnsonwhenovenis
pluggedinwithdoorclosed.
1.
Misadjustmentorloosewiringofsecondarylatch
switch
Adjustdoorandlatchswitches.
2. Defectivesecondarylatchswitch
5.
Timerstartscountdownbutno
microwaveoscillation.
(Noheatwhileovenlampand
fanmotorturnon)
1. Offalignmentoflatchswitches Adjustdoorandlatchswitches.
2.
Openorlooseconnectionofhighvoltagecircuit
especiallymagnetronfilamentcircuit
NOTE:
Largecontactresistancewillcauselower
magnetronfilamentvoltageandcausemagnetron
tohaveloweroutputand/orbeintermittent.
Checkhighvoltagecomponent
accordingtocomponenttest
procedureandreplaceifitis
defective.
3.
DefectivehighvoltagecomponentH.V.Inverter
PowerSupply(u)Magnetron
Checkhighvoltagecomponent
accordingtocomponenttest
procedureandreplaceifitis
defective.
4. OpenorloosewiringofpowerrelayB(RY1)
5. Defectiveprimarylatchswitch
6. DefectiveDPCorpowerrelayB(RY1) RefertoDPCtroubleshooting
6.
Ovencanprogrambuttimer
doesnotstartcountdown.
1.
Openorloosewiringofsecondarylatchswitch
2. Offalignmentofsecondarylatchswitch
3. Defectivesecondarylatchswitch
7.
Microwaveoutputislow.Oven
takeslongertimetocookfood.
1. Decreaseinpowersourcevoltage Consultelectrician
2.
Openorloosewiringofmagnetronfilamentcircuit.
(Intermittentoscillation)
3. Agingchangeofmagnetron
8.
Fanmotorturnsonandturntable
rotateswhendoorisopened.
1. Shortedprimarylatchswitch
9.
Ovendoesnotoperateand
returntopluggedinmodeas
soonasstartpadispressed.
1. DefectiveDPC
Checkgroundingconnectoron
escutcheonbase.
10.
Loudbuzzingnoisecanbe
heard.
1. Loosefanandfanmotor
11. Heaterdoesnotturnon.
1. Openorloosewiringofheater
2. Defectiveheater
3. Defectivepowerrelay
4. DefectiveDPC
12.
Ovenstopsoperationduring
cooking.
1.
Openorloosewiringofprimaryandsecondary
latchswitch
Adjustdoorandlatchswitches.
2. Operationofthermalcutout
7.3Troubleshootingofinvertercircuit(U)and
magnetronNEWH.V.