3 Control Panel Control Panel NN-A554/A524/A574* Display Window Time Pads Auto Weight Microwave Programs Auto Weight Combination Programs Auto Weight Defrost Programs (Chaos Defrost) Microwave Power Pad Grill Pad AUTO REHEAT Convection Pad Curry Chinese Combination Pad (10) Delay/Stand Pad: Pasta This can be used to delay a cooking Casserole...
4 Inverter Warnings The inverter circuit board supplies the magnetron tube with a very high voltage (4000 volts). HIGH VOLTAGE AREA *1 HEAT SINK DO NOT TOUCH RECTIFIER BRIDGE HOT/HIGH VOLTAGE *2 FILM CAPACITORS CHOKE COIL SAND BAR RESISTOR HIGH VOLTAGE...
6 Wiring Diagram NOTE WHEN REPLACIN ANY COMPONENT S RECONNECT THE WIRE HARNESS ACCORDIN T O THE COLOURS BELOW COL OURS INDICATED INSIDE BRACKETS () INDICATE THE COLOUR O THE CONNECTOR HOUSIN MA NETRON PRIMARY LATCH SWITCH CAUTION HEAT SINK (WH) (YE) (HOT LI E)
The output power is controlled by the inverter power 1. The digital programmer circuit determines the supply. The level of output from the inverter circuit is power level and the cooking time and indicates the controlled by a pulse width modulated signal from the operating state in the display.
The high voltage inverter circuit board must be connected to the microwave oven chassis. If the inverter board is not grounded it exposes very high voltages and causes extreme DANGER! Ensure that the inverter circuit is properly grounded via the inverter...
DO NOT measure the voltage in the high voltage circuit including the filament voltage of the magnetron. WARNING Never touch any circuit wiring during operation. 8.3 Part replacement When replacing any component in the microwave oven, always ensure that the power cord is removed from the wall outlet.
When the appliance is operated with the door hinges or magnetron fixed incorrectly, the microwave leakage can reach more than 5mW/cm . After repair or replac- ing parts, it is very important to check if the magnetron and the door hinges are correctly fixed. 8.7 Sharp edges Please use caution when unpacking, installing or mov- ing the unit, as some exposed edges may be sharp to...
PCB.figure 8 2. Remove the 1 screw holding air guide A. 6. Remove the 2 screws holding the inverter support- 3. Remove the 2 screws holding the tie bar. base to the oven chassis. 4. Remove the oven lamp and lead wire harness from 7.
9.3 Digital Programmer Circuit (DPC) 1. Carefully remove all solder from the terminal pins of and membrane key board. the low voltage transformer / power relays using a NOTE: Ground any static electric from your body before 30W soldering iron and a solder sucker. handling the digital programmer circuit (DPC).
After replacing component parts of the door, fol- low the instructions below for proper installation and adjustment of the door, this is to prevent microwave leakage. 1. When mounting the door to the oven, adjust the door parallel to the bottom of the oven face plate by adjusting the upper hinge.
Caution 10.2 Short switch and monitor circuit DO NOT try to repair this inverter power supply. 1. Unplug the lead wires from the high voltage inverter Replace this inverter power supply as a unit. primary terminals. 2. Connect the test probes of the ohm meter to these leads.
Page 16
10.6 Inverter power supply unit Warning Do not attempt to make any measurements in the high voltage circuit of the inverter or magnetron. See troubleshooting of the inverter circuit and magne- tron on <$elemtextto determine if the inverter power supply is still functioning.
11 Measurements and Adjustments Warning 4. Stir the water again and read the temperature of the water. (Record as T2). • Only replace parts with parts from the original man- 5. The normal temperature rise at the high power posi- ufacturer.
1. Do not try to repair the H.V. Inverter power supply. Replace the inverter circuit board as a complete unit. 2. Do not adjust the preset volume on the Inverter. It is very dangerous to repair or adjust without special test equiptment, the inverter handles very high voltage and current.
Page 19
(NOTE 1) switches. 3. Defective short switch (NOTE 1) 4. Defective Inverter power supply. (Refer to inverter circuit test pro- cedure on page) NOTE 1: All of these switches must be replaced at the same time. (Refer to adjustment instructions page)
Page 20
2. Defective steam sensor. pressed in sensor cooking mode. 12.4 Troubleshooting the inverter by input voltage Troubleshooting the Inverter circuit and magnetron Microwave oven shuts down between 15 - 33 seconds. If the microwave oven shuts down after a short period of time while operating in micropower mode, conduct the following test.
Page 21
12.5 Troubleshooting inverter by microwave oven input current This is an alternative way to test the inverter circuit by monitoring the input current to the microwave oven. The microwave oven shuts down between 15 and 33 seconds If the microwave oven shuts down after a short period of time while operating in micropower mode, conduct the following test.
It is very dangerous to repair or adjust this H.V. Inverter fault. preset without correct test equipment. NOTE: Do not attempt to repair the inverter circuit board, replace the inverter circuit board with a new unit. 12.6 Digital programmer circuit troubleshooting SYMPTOM...
Page 23
Normal 1. Magnetron play and the microwave oven voltage at Pin 1 2. Inverter circuit stops working Program for 1 minute and per- form the following test 12.7 Checking the semiconductors using a resistance meter Diode...
Need help?
Do you have a question about the Inverter NN-A574SBBTQ and is the answer not in the manual?
Questions and answers