7 TROUBLESHOOTING GUIDE
DANGER: HIGH VOLTAGES
1.
DO NOT RE-ADJUST PRESET CONTROL on the H.V.Inverter (U).
It is very dangerous to repair or adjust without proper test equipment
because this circuit generates very large current and high voltage. Operating a misaligned inverter circuit is dangerous.
2. Ensure proper grounding before troubleshooting.
3. Be careful of the high voltage circuitry, taking necessary precautions when troubleshooting.
4. Discharge high voltage remaining in the H.V.Inverter (U).
5. When checking the continuity of the switches or the H.V.Inverter, disconnect one lead wire from these parts and then check continuity with the
AC plug removed. Doing otherwise may result in a false reading or damage to your meter. When disconnecting a plastic connector from a
terminal, you must hold the plastic connector instead of the lead wire and then disconnect it, otherwise lead wire may be damaged or the
connector cannot be removed.
6. Do not touch any parts of the circuitry on the digital programmer circuit, since static electric discharge may damage this control panel. Always
touch ground while working on this panel to discharge any static charge in your body.
7. 230V AC is present on the digital programmer circuit (Terminals of power relay’s and primary circuit of Digital Programmer Circuit). When
troubleshooting, be cautious of possible electrical shock hazard.
Before troubleshooting, operate the microwave oven following the correct operating procedures in the instruction manual in order
to find the exact cause of any trouble, since operator error may be mistaken for the oven’s malfunction.
7.1. (Troubleshooting) Oven stops operation during cooking
SYMPTOM
CAUSE
CORRECTIONS
1.
Oven stops in 3 seconds
after
pressing [start] pad.
No input AC is supplied to H.V.Inverter (U)
CN702 terminals
1.
2.
3.
Latch Switch
Power relay RY1
Loose lead wire connector CN701, CN702
Oven stops in 23 seconds
after
pressing [start] pad.
H.V.Inverter (U) operates by the control signals
from DPC but magnetron is not oscillating
1.
2.
Magnetron
Loose lead wire connector CN703
Oven stops in 1 minute
after
pressing [start] pad.
Oven thermistor circuit is not functioning
1.
2.
Oven thermistor
Loose wiring
Oven stops in 3 minutes
after
pressing [start] pad.
Magnetron thermistor circuit is not functioning
1.
2.
Magnetron thermistor
Loose wiring
Oven stops in 30 seconds
after
pressing start pad. (Steam cooking)
Steam
heater
thermistor
circuit
is
not
functioning.
1.
2.
3.
Steam heater thermistor
Loose wiring
Bad conductibility between thermistor and steam
heater
2. No display and no operation at all.
Fuse is blown.
Most probably loose connection of connectors,
or door latch mechanism is not adjusted properly
1.
2.
Align door, Door Latch Switches
Loose wiring connectors
30
NN-CS894S
Summary of Contents for NN-CS894S
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