Panasonic NN-ST658W, NN-SD698S, NN-ST678S manual Troubleshooting Other problems

NN-SD698S / NN-ST678S / NN-ST658W

8.2.(Troubleshooting) Other problems

	SYMPTOM		CAUSE	CORRECTIONS
1.	Oven is dead.	1.	Open or loose lead wire harness
	Fuse is OK.	2.	Open thermal cutout / thermistor	Check thermal cutout is defective.
	No display and no operation at all.	3.	Open low voltage transformer
		4.	Defective DPC
2.	No display and no operation at all.	1.	Shorted lead wire harness	Check adjustment of primary, secondary latch
	Fuse is blown.	2.	Defective primary latch switch (NOTE 1)	switch and monitor interlock switch including
		3.	Defective monitor interlock switch (NOTE 1)	door.
		4.	Defective Inverter Power Supply (U)
			NOTE 1:
			All of these switches must be replaced at the same time.
			Check continuity of power relay RY1 contacts (between 1 and 2) and if it has continuity, replace
			power relay RY1 also.
3.	Oven does not accept key input	1.	Key input is not in proper sequence	Refer to operation procedure.
	(Program)	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	1.	Misadjustment or loose wiring of secondary	Adjust door and latch switches.
	plugged in with door closed.		latch switch
		2.	Defective secondary latch switch
		3.	Door switch CN3
5.	Timer starts count down but no	1.	Off-alignment of primary latch switch	Adjust door and latch switches.
	microwave oscillation.	2.	Open or loose connection of high voltage
	(No heat while oven lamp and fan		circuit especially magnetron filament circuit
	motor turn on)		NOTE:
			Large contact resistance will cause lower
			magnetron filament voltage and cause
			magnetron to have lower output and/or be
			intermittent.
		3.	Defective high voltage component	Check high voltage component according to
			H.V. Inverter Power Supply (U)	component test procedure and replace if it is
			Magnetron	defective.
		4.	Open or loose wiring of power relay RY1
		5.	Defective primary latch switch
		6.	Defective DPC or power relay RY1	Refer to DPC troubleshooting
6.	Oven can program but timer does not	1.	Open or loose wiring of secondary latch switch
	start countdown.	2.	Off-alignment of secondary latch switch
		3.	Defective secondary latch switch
7.	Microwave output is low. Oven takes	1.	Decrease in power source voltage	Consult electrician
	longer time to cook food.	2.	Open or loose wiring of magnetron filament
			circuit.(Intermittent oscillation)
		3.	Aging change of magnetron
8.	Fan motor turns on and turntable	1.	Low voltage transformer on DPC.
	motor rotates when door is opened.
9.	Oven does not operate and return to	1.	Defective DPC	Check grounding connector on escutcheon
	plugged in mode as soon as [Start]			base.
	pad is pressed.
10.	Loud buzzing noise can be heard.	1.	Loose fan and fan motor
11.	Turntable motor does not rotate.	1.	Open or loose wiring of turntable motor
		2.	Defective turntable motor
12.	Oven stops operation during cooking.	1.	Open or loose wiring of primary and	Adjust door and latch switches.
			secondary latch switch
		2.	Operation of thermal cutout

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