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NO

COM

NC

COM 

NO

COM

A. PRIMARY INTERLOCK SWITCH TEST

When the door release button is depressed slowly
with the door closed, an audible click should be
heard at the same time or successively at
intervals. When the button is released slowly, the
latches should activate the switches with an
audible click.
If the latches do not activate the switches when
the door is closed, the switches should be a
adjusted in accordance with the adjustment
procedure. Disconnect the wire lead from the
primary switch. Connect the ohmmeter leads to
the common (COM) and normally open (NO)
terminal of the switch. The meter should indicate
an open circuit in the door open condition.
When the door is closed, the meter should
indicate a closed circuit. 
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.

B. SECONDARY INTERLOCK SWITCH TEST

Disconnect the wire lead from the secondary
switch. 
Connect the ohmmeter leads to the common
(COM) and normally open (NO) terminals of the
switch. The meter should indicate a open circuit in
the door open condition. When the door is closed,
meter should indicate an closed circuit. When the
secondary switch operation is abnormal, make the
necessary adjustment or replace the switch only
with the same type of switch.

C. MONITOR SWITCH TEST

Disconnect the wire lead from the monitor switch.
Connect the ohmmeter leads to the common
(COM) and normally closed (NC) terminals of the
switch. The meter should indicate closed circuit in
the door open condition. When the door is closed,
meter should indicate an open circuit. When the
monitor switch operation is abnormal, replace with
the same type of switch.
NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity 
test before operating the oven.

5-7

MEASUREMENT OF MICROWAVE POWER OUTPUT

WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION

EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
ALL THESE SWITCHES MUST BE REPLACED AT THE SAME TIME.

TYPE NO.SZM-V 16-FA-63 OR VP-533A-OF FOR PRIMARY SWITCH
TYPE NO.SZM-V 16-FA-62 OR VP-532A-OF FOR MONITOR SWITCH
TYPE NO.SZM-V 16-FA-63 OR VP-533A-OF FOR SECONDARY SWITCH

COMPONENTS TEST 

PROCEDURE 

RESULTS

SWITCHES 

Check for continuity of the 

Door

Door

(Wire leads removed) 

switch with an Ohm-meter

open

closed

Primary
Switch

Monitor
Switch

Secondary
Switch

NOTE : After checking for the continuity of switches, make sure that are

connected correctly.

Summary of Contents for NN-E205CB EPG

Page 1: ...distribution is a violation of law Specifications Power Requirement Power Output Microwave Frequency Magnetron Timer Outside Dimensions Cavity Dimensions Net Weight Shipping weight 230 Volts AC 50 Hz 1100 Watts Single phase 3 wire grounded 800 Watts full microwave power IEC60705 2450 MHz 2M167B M47J1 0 60 min 455 W x 252 H x 320 D mm 315 W x 203 H x 294 D mm 10 5 kg approx 11 5 kg approx Specifica...

Page 2: ...r and other damage 4 damage to or loosening of hinges and latches 5 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 wave guide or transmission line and cavity for proper alignment integrity and connections D Any defective or misadjusted components in the interlock monitor door seal...

Page 3: ...4 1 OPERATING SEQUENCE 4 2 SCHEMATIC DIAGRAM 4 3 CIRCUIT DESCRIPTION 4 4 SERVICE INFORMATION 5 1 TOOLS AND MEASURING INSTRUMENTS 5 1 MICROWAVE LEAKAGE TEST 5 1 MEASUREMENT OF MICROWAVE POWER OUTPUT 5 3 DISASSEMBLY AND ADJUSTMENT 5 3 INTERLOCK CONTINUITY TEST 5 7 COMPONENT TEST PROCEDURE 5 8 TROUBLE SHOOTING 5 12 EXPLODED VIEW 6 1 REPLACEMENT PARTS LIST 7 1 ...

Page 4: ... only It is not recommended for commercial purposes DESCRIPTION Microwave Power for Variable Cooking Power level Max High 600W Medium 360W Low cDefrost Defrost 90W Warm Owner s manual Glass turntable Roller rest ITEM Control Complement Rating Label Location Accessories Back Side ...

Page 5: ...operation of the microwave oven requires that the magnetron be assembled to the waveguide and cavity Never operate the magnetron unless it is properly installed Be sure that the magnetron gasket is properly installed around the dome of the tube whenever installing the magnetron 2 1 CAUTIONS Unlike other appliances the microwave oven is high voltage and high current equipment Though it is free from...

Page 6: ...lat surface at least 10 cm 4 inches from the wall 7 Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference EARTHING INSTRUCTIONS This microwave oven is designed to be used in a fully earthed condition It is imperative therefore to make sure it is properly earthed before servicing WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT As the colors of the wire...

Page 7: ...PANEL Roller Rest Turntable Oven Front Plate Window Door Screen Door Seal Safety Door Lock System Control Panel NN E205WB NN E205CB NN E235MB UK 1 POWER CONTROL KNOB Used to select power level for cooking 2 TIMER KNOB Used to set the cooking time ...

Page 8: ...the end of cooking time you will a single ring sound and the lamp is turn off NOTE Each number represents minutes To ensure accurate timing it is advisable to turn the timer knob slightly passed the desired cooking time and then back to the proposed setting Press the door opener to check the cooking condition during oven operation Opening the door during oven operation automatically turns off the ...

Page 9: ...s rotating 3 2 volts AC is generated from the filament winding of the high voltage transformer This 3 2 volts is applied to the magnetron to heat the magnetron filament through two noise preventing choke coils A high voltage of approximately 2100 volts AC is generated in the secondary of the high voltage transformer which is increased by the action of the diode and charging of the high voltage cap...

Page 10: ...ervicing The power density of the microwave radiation leakage emitted by the microwave oven should not exceed 5 mW cm2 Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage NECESSARY MEASURING INSTRUMENTS TESTER VOLTS DC AC Ohmmeter Microwave survey meter Holaday HI 1500 HI 1501 Narda 8100 8200 Inch scale 600 cc non conductive material beaker gl...

Page 11: ...than 1 inch sec 2 5 cm sec along the shaded area otherwise a false reading may result The test probe must be held with the grip portion of the handle A false reading may result if the operator s hand is befween the handle and the probe When testing near a corner of the door keep the probe perpendicular to the surface making sure the probe horizontally along the oven surface this may possibly cause...

Page 12: ...pty vessel are at ambient temperature prior to the start of the test The initial temperature T1 of the water is 10 2 C It is measured immediately before the water is added to the vessel After addition of the water to the vessel the load is immediately placed on the center of the turntable which is in thd lowest position and the microwave power switched on The time T for the temperature of the wate...

Page 13: ...RMER REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from magnetron high voltage transformer and capacitor 3 Remove the screw holding the high voltage transformer to the baseplate F FAN MOTOR ASSEMBLY REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from fan motor noise filter and high voltage capacitor 3 Remove the two screws holding the the suctio...

Page 14: ...at gasket is rigidly attached to the magnetron To prevent microwave leakage tighten the mounting screws properly making sure there is no gap between the waveguide and the magnetron J REMOVING THE TURNTABLE MOTOR 1 Remove the turntable 2 Remove the turntable shaft VERY CAREFULLY 3 Lay the unit down on its back 4 Remove the turntable motor cover The turntable base cover is easily removed by pinching...

Page 15: ...OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch board to the oven assembly Adjust the latch board in the arrow direction so that oven door will not have any play in it when the door is closed Tighten the mounting screw Check for play in the door by pushing the door release button Door movement should be less than 0 5 mm 1 64 inch Don t push the door release button while making adjustment M...

Page 16: ...er should indicate an closed circuit When the secondary switch operation is abnormal make the necessary adjustment or replace the switch only with the same type of switch C MONITOR SWITCH TEST Disconnect the wire lead from the monitor switch Connect the ohmmeter leads to the common COM and normally closed NC terminals of the switch The meter should indicate closed circuit in the door open conditio...

Page 17: ...R IN THE OVEN HIGH VOLTAGE TRANSFORMER Wire leads removed MAGNETRON Wire leads removed Approx 1 4 ohm Approx 90 ohm Less than 1 ohm Normal Infinite Normal Infinite Normal Less than 1 ohm Normal Infinite PRIMARY TERMINAL SECONDARY FILAMENT WINDING COMPONENTS TEST PROCEDURE RESULTS 1 Measure the resistance Ohm meter scale Rx1 Primary winding Secondary winding Filament winding 2 Measure the resistanc...

Page 18: ...nal Normal Momentarily indicates several ohms and then gradually returns to infinite Normal Infinite Normal Continuity Abnormal Infinite Normal Infinite Abnormal Continuity Measure the resistance Ohm meter scale Rx1000 Terminal to case Measure the continuity Forward Ohm meter scale Rx10000 Measure the continuity Reverse Ohm meter scale Rx10000 HIGH VOLTAGE DIODE NOTE Some inexpensive meters may in...

Page 19: ...NOTE If the fuse is blown check the primary the secondary and the monitor switches H V D and H V C before replacing the fuse If the fuse is blown by improper switch operation replace the defective switch and the fuse at the same time Replace just the fuse if the switches operate normally Normal Abnormal ...

Page 20: ... Normal Approx 100 200 kohm Abnormal Infinite or several ohm Note A is ON OFF switch B is power supply terminal of the timer motor C is defrost switch NOTE A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION WHEN REMOVING THE WIRE LEADS FROM THE PARTS BE SURE TO GRASP THE CONNECTOR NOT THE WIRES A B A C 30 ...

Page 21: ...d for a longer time period Do not use metallic ware for cooking except where noted in the cooking guide Do not use any type of cookware with metallic trimming CAUSE REMEDY Excessive weight on tray or improperly balanced Distribute food evenly Cook smaller portions and or use lighter weight cookware Turntable drags or makes noise TROUBLE SHOOTING CAUTIONS 1 Check grounding before checking for troub...

Page 22: ...former Malfunction of the monitor switch Replace fuse primary monitor and secondary switches Check continuity of monitor switch with door closed Check continuity of primary switch with door opened Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit Replace fuse TROUBLE 1 Oven lamp does not turn on when the timer knob is pushed with doo...

Page 23: ...CONDITION CHECK RESULT CAUSE REMEDY 1 Oven does not operate No continuity No continuity No continuity No continuity Malfunction of the primary switch Malfunction of the secondary switch Malfunction of the timer switch Faulty thermostat Adjust or replace Adjust or replace replace replace Check the continuity of the primary switch with door closed Check the continuity of the secondary switch with se...

Page 24: ...or burn out Abnormal Abnormal Defective monitor resistor Defective AC relay Open the secondary winding of the high voltage transformer of faulty insulation of filament winding Replace Replace Replace Check the monitor resistor Check the AC realy Check the AC realy Normal Abnormal Shorted H V diode Replace Check H V diode Abnormal Faulty capacitor Replace Check H V capacitor Abnormal Faulty magnetr...

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