Panasonic ne-1037 BTQ User manual

© 2007 Panasonic Home Appliances Microwave
Oven (Shanghai) Co., Ltd. All rights reserved.
Unauthorized copying and distribution is a violation
of law.
NE-1027
NE-1037
BTQ (U.K.)
ETG (Continental Europe)
Microwave Oven
ORDER NO.PHAMOS0705021C2

2
NE-1027 / NE-1037

1 CONTROL PANEL 4
1.1. NE-1027 4
1.2. NE-1037 5
2 OPERATION PROCEDURE 6
2.1. Manual Heating for Single Stage 6
2.2. Manual Heating for 2nd Stage 6
2.3. Memory Setting for Single Stage Operation Oven is not in
program lock mode. 6
2.4. Memory setting for 2nd stage 7
2.5. Memory Pad Heating 7
2.6. To Read Cycle Counter 8
2.7. To Select Beep Tone Options (ON/OFF of Beep Tone) 8
2.8. To Lock Program of Memory Pad 8
2.9. To Release the Memory Pad Program Lock 8
3 SCHEMATIC DIAGRAM 9
3.1. NE-1027 9
3.2. NE-1037 10
4 DESCRIPTION OF OPERATING SEQUENCE 11
4.1. Variable power cooking control (NE-1027) 11
4.2. Variable power cooking control (NE-1037) 11
5 CAUTIONS TO BE OBSERVED WHEN TROUBLESHOOTING
12
5.1. Check the earthing 12
5.2. If the door lock, the door switch, the door seal or the door
develops a malfunction, be sure not to operate the oven
until complete repairs are made. 12
5.3. Warning about the electric charge in the high voltage
capacitor 12
5.4. When parts must be replaced, remove the power plug
from the outlet. 13
5.5. When the 10 Amp/2.5 Amp fuse is blown due to the
operation of short switch: 13
5.6. Avoid inserting nails, wire, etc. through any holes in the
unit during operation. 13
5.7. Confirm after repair 13
6 DISASSEMBLY AND PARTS REPLACEMENT PROCEDURE
14
6.1. Magnetron 14
6.2. Digital Programmer Circuit (D.P.C.) and membrane
keyboard. (NE-1037) 14
6.3. Low voltage transformer and/or power relays (RY1, RY2,
RY3, RY4) (NE-1037) 15
6.4. Fan motor 15
6.5. Stirrer motor 15
6.6. Door assembly 16
6.7. Temp sensor (thermal protector) (NE-1037) 16
6.8. Floor shelf and/or moving antenna 16
7 COMPONENT TEST PROCEDURE 17
7.1. Primary Latch Switch, (Door Switch and Power Relay B)
Interlocks. 17
7.2. Short Switch & Monitor 17
7.3. High voltage transformer 17
7.4. High voltage capacitor 17
7.5. Magnetron 17
7.6. Variable power controller (NE-1027) 18
7.7. Diode 18
7.8. Protector diode 18
7.9. Membrane key board (Membrane switch assembly)(NE-
1037) 18
7.10. Temp sensor (Thermal protector) (NE-1037) 18
8 MEASUREMENTS AND ADJUSTMENTS 19
8.1. Adjustment of Safety switch A, Safety switch B and short
switch 19
8.2. Measurement of microwave output 19
9 TROUBLESHOOTING GUIDE 20
9.1. NE-1027 20
9.2. NE-1037 22
10 EXPLODED VIEW AND PARTS LIST 26
10.1. EXPLODED VIEW 26
10.2. PARTS LIST 27
10.3. DOOR ASSEMBLY 28
10.4. ESCUTCHEON BASE ASSEMBLY 29
10.5. PACKING AND ACCESSORIES 31
10.6. WIRING MATERIALS 32
11 DIGITAL PROGRAMMER CIRCUIT (NE-1037) 33
11.1. SCHEMATIC DIAGRAM 33
CONTENTS
Page Page
3
NE-1027 / NE-1037

1 CONTROL PANEL
1.1. NE-1027
4
NE-1027 / NE-1037

1.2. NE-1037
5
NE-1027 / NE-1037

2.1. Manual Heating for Single
Stage
OPERATION DISPLAY
1. Plug the power supply cord into
wall receptacle.
2. Open the door.
Place a water load in the oven
and close the door.
3. Press Power Level pad
once.
(Sets to HIGH power)
4. Press 2 ,0,0 pads.
(Sets to 2 minutes)
5. Press Start pad.
(Sets to 2 minutes)
6. When cooking time has
elapsed, oven beeps 5 times
and shuts off. Display blinks
zero.
7. Open the door and take out the
water load. Display stops
blinking.
8. Close the door.
1 minute later, display will return
blank.
2.2. Manual Heating for 2nd Stage
OPERATION DISPLAY
1. Follow step 1 to 4 for 1st stage.
2. Press Power Level pad 2
times.
(Sets MED power)
OPERATION DISPLAY
3. Press 1 ,0,0 pads.
(Sets to 1 minute)
4. Press Start pad. Total time
for both stages will be
displayed.
5. When the 1st stage cooking
time has elapsed, oven beeps
once and automatically
switches to 2nd stage cooking.
(2nd stage)
6. When cooking time has
elapsed, oven beeps 5 times
and shuts off. Display blinks
zero.
7. Open the door and take out the
water load. Display stops
blinking.
8. Close the door.
1 minute later, display will turn
blank.
2.3. Memory Setting for Single
Stage Operation Oven is not in
program lock mode.
OPERATION DISPLAY
1. Press Prog pad.
NOTE: Display must be blank to
start programming.
2. Press 5 pad.
(Sets to memory pad 5)
3. If memory was previously
programmed, the pad number
and the previously selected
time and power level will
appear in the display.
2 OPERATION PROCEDURE
6
NE-1027 / NE-1037

OPERATION DISPLAY
4. The pad number and Stage
Heating Indicator will appear in
the display again.
5. Press Power Level pad 2
times.
(Sets to MED power)
6. Press 3 ,0 pads.
(Sets to 30 seconds)
7. Press Prog pad again.
8. 2 seconds later, the time and
power level setting for single
stage will appear in the display.
9. 2 seconds later, Double
Quantity Heating Indicator and
then the double heating time
will appear in the display.
10. 2 seconds later, the display will
go blank.
2.4. Memory setting for 2nd stage
OPERATION DISPLAY
1. Follow steps 1 to 6 for memory
setting for single stage.
(MED power, 30 seconds for 1st
stage)
2. Press Power Level pad 3
times.
(Sets defrost power for 2nd
stage)
3. Press 2 ,0,0 pad.
4. Press Prog pad.
OPERATION DISPLAY
5. 2 seconds later, the display
shows your setting program.
6. This indicates double cooking
time.
Example:
This means:
If you press "5", oven will
operate 30 sec-MED, 2 min-
DEF.
If you press "X2" and "5" oven
will operate 1 min-MED, 4 min-
DEF.
7. After all of your programming
has been completed, the
display will go blank.
2.5. Memory Pad Heating
OPERATION DISPLAY
1. Plug the power supply cord into
wall receptacle.
2. Open the door.
Place a water load in the oven
and close the door.
3. Press 7 pad.
(Sets for 2 minutes)
4. Press Start pad.
5. When cooking time has
elapsed, oven beeps 5 times
and shuts off. Display blinks
zero.
6. Open the door and take out
water load. Display stops
blinking.
7
NE-1027 / NE-1037

OPERATION DISPLAY
7. Close the door, display will
return blank after 1 minute.
2.6. To Read Cycle Counter
OPERATION DISPLAY
1. Open the door and leave it
open.
2. While pressing Stop/Reset
pad, press Power Level
pad. eg. 0010 means the oven
has been used 1,000 times.
9999 means the oven has
been used 999,900 times.
3. 2 seconds later, the display will
return to "0".
2.7. To Select Beep Tone Options
(ON/OFF of Beep Tone)
OPERATION DISPLAY
1. Open the door.
2. Press Prog pad.
3. Press 0 pad.
4. Press 0 pad again.
(No beep tone setting)
5. Press Prog pad again.
You have completed
programming the beep tone
option.
6. 2 seconds later, the display will
return to "0".
2.8. To Lock Program of Memory
Pad
OPERATION DISPLAY
1. Plug the power supply cord into
wall receptacle.
- Display must be blank -
2. Press and hold in the Prog
pad until the display shows "P"
and "L".
(Approximately 6 seconds)
NOTE: When oven is in
"program lock mode", display
will not show anything and
remain blank.
2.9. To Release the Memory Pad
Program Lock
OPERATION DISPLAY
1. Plug the power supply cord into
wall receptacle.
2. While pressing and holding the
Stop/Reset pad, press and
hold in the Prog pad until
the display shows "P".
(Approximately 6 seconds)
NOTE:
When oven is in "program
unlock mode", display will not
show anything and remain
blank.
8
NE-1027 / NE-1037

4.1. Variable power cooking
control (NE-1027)
The vari-power controller controls the ON-OFF time of the vari-
power switch to vary the output power of the microwave oven
from "100" to "1000". The vari-power controller is a part of the
timer assembly. The timer assembly consists of timer motor,
timer switch, vari-power switch and the combination of gears,
cam and actuater lever.
One complete cycle of the vari-power controller is 26 seconds,
in which the vari-power switch is turned "on" or "off" by the cam
rotation is the 26 ± 2 second period.
By controlling the timing of the vari-power switch "on" period,
the power AC supplied to the high voltage transformer is
interrupted intermittently so that the average output power of
the microwave oven is varied.
Table shows the timing chart of vari-power switch operation in
respect to the power setting on the control panel.
NOTE:
The ON/OFF time ratio does not correspond with the
percentage of microwave power since approximately 2
seconds are required for heating of magnetron
filament.
OUTPUT ON-OFF TIME OF
POWERSETTING POWER(W) A
PPROX.
VARI-POWER SWITCH
(Mechanical timer model)
ON(SEC) OFF(SEC)
1000 1000 26 0
600 600 20 6
440 440 15 11
DEFROST 340 10 16
250 250 8 18
100 100 4 22
4.2. Variable power cooking
control (NE-1037)
The coil of power relay B (RY1) is energized intermittently by
the digital programmer circuit, when the oven is set at any
power selection except for High power position. The digital
programmer circuit controls the ON-OFF time of power relay B
contacts in order to vary the output power of the microwave
oven from "Low" to "High" power. One complete ON and OFF
cycle of power relay B is 22 seconds. The relation between
indications on the control panel and the output of the
microwave oven is as shown in table.
NOTE:
The ON/OFF time ratio does not correspond with the
percentage of microwave power since approximately 2
seconds are required for heating of magnetron
filament.
*OUTPUT ON-OFF TIME OF
POWER SETTING POWER(W) POWER RELAY B (RY1)
APPROX. ON(SEC) OFF(SEC)
HIGH 1000 22 0
MEDIUM 500 11 11
DEFROST 340 8 14
*IEC-705-88 test procedure.
Specifications Subject to change without notice
4 DESCRIPTION OF OPERATING SEQUENCE
11
NE-1027 / NE-1037

Unlike many other appliances, the microwave oven is high-
voltage, high-current equipment. Though it is free from danger
in ordinary use, extreme care should be taken during repair.
CAUTION
Servicemen should remove their watches whenever working close to
or replacing the magnetron.
5.1. Check the earthing
Do not operate on a 2 wire extension cord. The microwave
oven is designed to be used in a completely earthed condition.
It is imperative, therefore, to make sure it is properly earthed
before beginning repair work.
5.2. If the door lock, the door
switch, the door seal or the
door develops a malfunction,
be sure not to operate the
oven until complete repairs
are made.
If the oven is operated with any of these parts in imperfect
condition, hazardous microwave leakage might occur.
WARNING
Never operate the oven until the following are confirmed:
(A) The door is tightly closed.
(B) There is no broken hinge or door arm.
(C) The door seal is not damaged.
(D) The door is not bent or warped.
(E) There is no other visible damage.
5.3. Warning about the electric
charge in the high voltage
capacitor
For about 30 seconds after the oven is turned off, an electric
charge remains in the high voltage capacitor.When replacing or
checking parts, remove the power plug from the outlet and
short the terminal of the high voltage capacitor (terminal of lead
wire from diode) to chassis ground with an insulated handle
screwdriver to discharge.
WARNING
There is high-voltage present, with high-current capabilities in the
circuits of the high voltage winding and filament winding of the high
voltage transformer. It is extremely dangerous to work on or near
these circuits with oven energized.
DO NOT measure the voltage in the high voltage circuit including
filament voltage of magnetron.
WARNING
Never touch any circuit wiring with your hand nor with an insulated
tool during operation.
5 CAUTIONS TO BE OBSERVED WHEN
TROUBLESHOOTING
12
NE-1027 / NE-1037

5.4. When parts must be replaced,
remove the power plug from
the outlet.
5.5. When the 10 Amp/2.5 Amp
fuse is blown due to the
operation of short switch:
WARNING
When the 10 Amp/2.5 Amp fuse is blown due to operation of the
interlock monitor switch, you must replace all of the components
(Primary latch switch, Door switch, Short switch and Power relay B
(RY1)).
1. This is mandatory. Refer to “Adjustments and
Measurement” for these switches.
2. When replacing the fuse, confirm that it has the appropriate
rating for these models.
3. When replacing faulty switches, be sure mounting tabs are
not bent, broken or otherwise deficient in their ability to hold
the switches.
5.6. Avoid inserting nails, wire, etc.
through any holes in the unit
during operation.
Never insert a wire, nail or any other metal object through the
lamp holes on the cavity or any other holes or gaps, because
such objects may work as an antenna and cause microwave
leakage.
5.7. Confirm after repair
1. After repair or replacement of parts, make sure that the
screws of the oven, etc. are neither loose nor missing.
Microwaves might leak if screws are not properly tightened.
2. Make sure that all electrical connections are tight before
inserting the plug into the wall outlet.
3. Check for microwave energy leakage. (Refer to procedure
for measuring microwave evergy leakage.)
CAUTION
MICROWAVE RADIATION
USE CAUTION NOT TO BECOME EXPOSED TO RADIATION
FROM THE MICROWAVE MAGNETRON OR OTHER PARTS
CONDUCTING MICROWAVE ENERGY.
IMPORTANT NOTICE
1.The following components have potentials above 2000V while the
appliance is operated.
* Magnetron
* High voltage transformer
* High voltage diode
* High voltage capacitor
Pay special attention to these areas.
2.When the appliance is operated with the door hinge or magnetron
adjusted incorrectly, the microwave leakage can exceed more than
5mW/cm2. After repair or exchange, it is very important to check that
magnetron and the door hinge is correctly installed.
13
NE-1027 / NE-1037

6.1. Magnetron
1. Discharge the high voltage capacitor.
2. Remove 2 screws holding magnetron thermal cutout.
3. Remove 1 screw holding air guide A.
4. Disconnect 2 high voltage lead wires from magnetron
filament terminals.
5. Remove 4 screws holding the magnetron.
NOTE:
After replacement of the magnetron, tighten mounting
screws properly making sure there is no gap between
the waveguide and the magnetron to prevent
microwave leakage.
CAUTION
When replacing the magnetron, be sure the antenna gasket is in
place.
CAUTION
When connecting 2 filament lead wires to the magnetron terminals,
be sure to connect the lead wires in the correct position. The lead wire
of high voltage transformer should be connected to "F terminal" and
the lead wire from high voltage capacitor should be connected to "FA
terminal".
6.2. Digital Programmer Circuit
(D.P.C.) and membrane
keyboard. (NE-1037)
NOTE:
Be sure to ground any static electric charge built up on
your body before handling the D.P.C.
1. Disconnect all connectors from D.P.C.
2. Remove 2 screws holding escutcheon base and slide the
escutcheon base upward slightly.
3. Release flat cable connector´s lock of D.P.C. by pushing
both levers to inside and pull them upward, and remove flat
cable of membrane key board.
4. Remove 3 screws holding D.P.C.
To replace membrane key board
5. Remove escutcheon bracket from escutcheon base by
freeing 4 catch hooks on the escutcheon base.
6. Remove metal trim from escutcheon base.
7. Peel off the tab of membrane key board from escutcheon
base.
8. Peel off the display filter from escutcheon base.
9. Push the upper part of key board (display window portion)
from back of escutcheon base and peel off escutcheon
sheet and membrane key board completely from
escutcheon base.
NOTE:
1. The membrane key board is attached to the
escutcheon base with double faced adhesive tape.
Therefore, applying hot air such as using a hair dryer is
recommended for smoother removal.
2. When installing new membrane key board, make
sure that the surface of escutcheon base is cleaned
sufficiently so that any problems (shorted contacts or
uneven surface) can be avoided.
3. Alignment position of membrane key board;
Membrane key board: Right and upper edges
Escutcheon sheet: Right and upper edges
6 DISASSEMBLY AND PARTS REPLACEMENT
PROCEDURE
14
NE-1027 / NE-1037

6.3. Low voltage transformer
and/or power relays (RY1,
RY2, RY3, RY4) (NE-1037)
NOTE:
Be sure to ground any static electric charge built up on
your body before handling the D.P.C..
1. Using solder wick or a desoldering tool and 30W soldering
iron, carefully remove all solder from the terminal pins of the
low voltage transformer and/or power relays.
NOTE:
Do not use a soldering iron or desoldering tool of
more than 30 watts on D.P.C. contacts.
2. With all the terminal pins cleaned and seperated from
D.P.C. contacts, remove the defective transformer/power
relays and install new transformer/power relays making
sure all terminal pins are inserted completely. Resolder all
terminal contacts carefully.
6.4. Fan motor
1. Disconnect 2 lead wires from fan motor terminals.
2. Disconnect 3 lead wires from noise filter P.C.B. terminals.
3. Disconnect 4 high voltage lead wires from high voltage
capacitor terminals.
4. Remove 5 screws holding fan motor and orifice assy,
detach the orifice assy with fan motor from oven assy.
5. Remove fan blade from the fan motor shaft by pulling it
straight Out.
6. Separate the fan motor from the orifice assy by freeing 2
catch hooks on the orifice assy.
6.5. Stirrer motor
1. Remove the motor cover by breaking off at the 8 spots
indicated by arrows with a cutter or the like. (See Figure)
Note:
After breaking off the motor cover, make sure the cut-off
portions are properly trimmed off or bend to inside so
that no sharp edge will expose to outside.
2. Disconnect 2 lead wires connected to the stirrer motor.
3. Remove the stirrer motor by removing 2 screws.
Note:
To reinstall the motor cover, use 4x6 screw.
15
NE-1027 / NE-1037

6.6. Door assembly
1. Open the door and remove door C from door E by carefully
pulling outward starting from upper right hand corner.
2. Remove door key and door key spring.
3. Remove 2 screws holding side frame of door A.
4. Seperate the door A from the door E by freeing catch hooks
on the door A using a flat screwdriver.
After replacement of the defective component parts of
the door, reassemble it and follow the instructions
below for proper installation and adjustment so as to
prevent an excessive microwave leakage.
5. When mounting the door to the oven, be sure to adjust the
door parallel to the bottom line of the oven face plate by
moving the upper hinge and lower hinge in the direction
necessary for proper alignment.
6. Adjust so that the door has no play between the inner door
surface and oven front surface. If the door assembly is not
mounted properly, microwave power may leak from the
clearance between the door and oven.
NOTE:
Door alignment is crucial. If door is misaligned, apply
pressure until alignment is achieved.
NOTE:
After replacement of the defective component parts of
the door, reassemble, and perform microwave leakage
test.
6.7. Temp sensor (thermal
protector) (NE-1037)
1. Cut a lead wire at the top of sensor terminals.
2. Remove 1 screw holding the temp sensor and replace with
new one.
3. Solder the lead wires securely to the sensor terminals.
6.8. Floor shelf and/or moving
antenna
1. Insert a phillips type screwdriver or equivalent approx. 2"
(5 cm) in shaft length in the access hole in the left side oven
wall as shown in Figure.
2. Carefully lift up the floor shelf by prying up with the
screwdriver until the floor shelf is lifted up over the level of
oven front opening.
3. Remove the floor shelf by lifting it out through the oven
front.
To replace moving antenna.
4. Remove the moving antenna by simply lifting it up off the
stirrer motor shaft.
NOTE:
When replacing the moving antenna, make sure the
plastic stirrer spacers are correctly in place. They
are necessary to stabilize the antenna by gliding
around the oven bottom as the antenna turns.
16
NE-1027 / NE-1037

CAUTION
1. High voltage is present at the high voltage terminal of the high
voltage transformer during any cook cycle.
2. It is neither necessary nor advisable to attempt measurement of the
high voltage.
3. Before touching any oven components, or wiring, always unplug
the oven from its power source and discharge the high voltage
capacitor.
7.1. Primary Latch Switch, (Door
Switch and Power Relay B)
Interlocks.
1. Unplug the lead connectors to Power Relay B and verify
continuity of the power relay B 1-2 terminals.
2. Unplug lead connectors to primary latch switch and Door
Switch.
3. Test the continuity of switches at door opened and closed
positions with ohm meter (low scale).
Normal continuity readings should be as follows.
7.2. Short Switch & Monitor
1. Unplug lead wires from H.V.transformer primary terminals.
2. Connect test probes of ohm meter to the disconnected
leads of the H.V. transformer.
3. Test the continuity of short switch with door opened and
closed positions using lowest scale of the ohm meter.
Normal continuity readings should be as follows.
7.3. High voltage transformer
1. Remove connectors from the transformer terminals and
check continuity.
2. Normal (cold) resistance readings should be as follows:
Secondary winding........................... Approx. 60 Ω~120 Ω
Filament winding.............................. Approx. 0 Ω
Primary winding................................. Approx. 0 Ω~2 Ω
7.4. High voltage capacitor
1. Check continuity of capacitor with meter on highest OHM
scale.
2. A normal capacitor will show continuity for a short time, and
then indicate 9MΩonce the capacitor is charged.
3. A shorted capacitor will show continuous continuity.
4. An open capacitor will show constant 9MΩ.
5. Resistance between each terminal and chassis should be
infinite.
7.5. Magnetron
Continuity checks can only indicate an open filament or a
shorted magnetron. To diagnose for an open filament or
shorted magnetron:
1. Isolate magnetron from the circuit by disconnecting the
leads.
2. A continuity check across magnetron filament terminals
should indicate one ohm or less.
3. A continuity check between each filament terminal and
magnetron case should read open.
7 COMPONENT TEST PROCEDURE
17
NE-1027 / NE-1037

7.6. Variable power controller
(NE-1027)
1. Isolate variable power switch from the circuit by
disconnecting 2 leads.
2. In order to check if variable power controller is operating
normally, follow the test procedures below.
a. Select any power other than "900" and start the oven.
b. Check continuity between both terminals of the variable
power switch.
c. Variable power controller (timer and variable power
switch) is working properly if the ohm meter reads open
and 0 ohm within 26 ± 2 seconds interval as shown in
Table on description of operating sequence.
7.7. Diode
1. Isolate the diode from the circuit by disconnecting the leads.
2. With the ohmmeter set on the highest resistance scale,
measure the resistance across the diode terminals.
Reverse the meter leads and again observe the resistance
reading. Meter with 6V, 9V or higher voltage batteries
should be used to check the front-to-back resistance of the
diode, otherwise an infinite resistance may be read in both
directions.
A normal diode´s resistance will be infinite in one direction
and several hundred kΩin the other direction.
7.8. Protector diode
1. Isolate the protector diode assembly from the circuit by
disconnecting its leads.
2. With the ohmmeter set on the highest resistance scale,
measure the resistance across the protector diode
terminals.
Reverse the meter leads and again observe the resistance
reading. A normal protector diode´s resistance will be
infinite in both directions.
It is faulty if it shows continuity in one or both directions.
7.9. Membrane key board
(Membrane switch assembly)
(NE-1037)
Check continuity between switch terminals, by tapping an
appropriate pad on the key board. The contacts assignment of
the respective pads on the key board is as shown in digital
programmer circuit.
7.10. Temp sensor
(Thermal protector) (NE-1037)
A temp sensor is mounted on exhaust guide. Its purpose is to
automatically shut off the oven in case the cavity overheats for
any reason.
The thermal protector will operate at 257°F (125°C).
The device is connected to the D.P.C. on touch control models.
When the thermal protector exceeds its temperature it will turn
off the power to oven cavity and display wil go to reset mode.
The cooking program can be reset after cool-down.
18
NE-1027 / NE-1037

8.1. Adjustment of Safety switch A,
Safety switch B and short
switch
1. When mounting Safety switch A, Safety switch B and short
switch to door hook assembly, mount the Safety switch A,
Safety switch B and the short switch to the door hook
assembly as shown in table.
NOTE:
No specific adjustment during installation of Safety
switch A, Safety switch B and short switch to the
door hook is necessary.
2. When mounting the door hook assembly to the oven
assembly, adjust the door hook assembly by moving it in
the direction of arrow in table so that the oven door will not
have any play in it. Check for play in the door by pulling the
door assembly. Make sure that the latch keys move
smoothly after adjustment is completed. Completely tighten
the screws holding the door hook assembly to the oven
assembly.
3. Reconnect the short switch and check the continuity of the
monitor circuit and all latch switches again by following the
components test procedures.
8.2. Measurement of microwave
output
The output power of the magnetron can be determined by
performing IEC standard test procedures. However, due to the
complexity of IEC test procedures, it is recommended to test
the magnetron using the simple method outlined below.
Necessary Equipment:
• ••
•
1 litre beaker
• ••
•
Glass thermometer
• ••
•
Wrist watch or stopwatch
NOTE:
Check the line voltage under load. Low voltage will
lower the magnetron output. Take the temperature
readings and heating time as accurately as possible.
1. Fill the beaker with exactly one litre of tap water. Stir the
water using the thermometer and record the water’s
temperature. (recorded as T1).
2. Place the beaker on the center of glass tray.
Set the oven for High power and heat it for exactly one
minute.
3. Stir the water again and read the temperature of the water.
(recorded as T2).
4. The normal temperature rise at High power level for each
model is as shown in table.
TABLE (1L-1min.test)
RATED OUTPUT TEMPERATURE RISE
1000W Min.8.5°C
8 MEASUREMENTS AND ADJUSTMENTS
19
NE-1027 / NE-1037

9 TROUBLESHOOTING GUIDE
9.1. NE-1027
CAUTION
1. Check grounding before checking for trouble.
2. Be cafeful of the high voltage circuit.
3. Discharge high voltage capacitor.
4. When checking the continuity of the switches or the high voltage transformer, disconnect one lead wire from these parts and then check
continuity with the AC plug removed. To do 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 by removed.
First of all operate the microwave oven following the correct operating procedures in order to find the exact cause of any trouble.
9.1.1. [TROUBLE 1] Oven does not start cooking
SYMPTOM CAUSE CORRECTIONS
1. Oven is dead. 1. Open or loose lead wire harness
Fuses is OK. 2. Open thermal cutout (Magnetron)(Oven) Check fan motor when thermal cutout is defective.
2. No microwave oscillation. 1. Off-alignment of latch switches Adjust door and latch switches.
Other operation is OK. 2. Defective secondary latch switch (SW2)
3. Open or loose wiring of secondary latch switch,
vari-power switch and micro select switch
4. Defective variable power switch (SW7) Refer to component test procedure.
5. Open or loose connection of high voltage
circuit especially magnetron filament circuit
NOTE: Large contact resistance will bring lower
magnetron filament voltage and causing
magnetron to lower output and/or intermittent
oscillation.
6. Defective high voltage component
H.V. Transformer
H.V. Capacitor
H.V. Diode
Magnetron
Check high voltage component according to
component test procedure and replace if it is defective.
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NE-1027 / NE-1037

9.1.2. [TROUBLE 2] Fuse is blown
SYMPTOM CAUSE CORRECTIONS
1. 10A fuse is blown. 1. Shorted lead wire harness
2. Shorted H.V. Capacitor
3. Shorted H.V. Diode Replace H.V. Diode and protector diode
(*NOTE)
4. Defective magnetron Replace magnetron and protector diode
(*NOTE)
5. Shorted H.V. Transformer Replace H.V.Transformer and protector diode
(*NOTE)
6. Shorted Protector diode
2. 2.5A fuse is blown. 1. Defctive primary latch switch and short switch Check adjustment of primary, secondary latch
switch and short switch including door.
2. Open or loose wiring of power relay (RY2)
3. Defective power relay (RY2)
4. Defective relay control circuit
*NOTE:
Be sure to replace protector diode together with those H.V.components.
In this case, only D2 of protector diode may be shorted due to faulty H.V.component. Therefore,
if protector diode is not replaced together, high voltage transformer will be damaged (over
heated).
9.1.3. [TROUBLE 3] Other troubles
SYMPTOM CAUSE CORRECTIONS
1. Microwave output is low. 1. Decrease in power source voltage Consult electrician
Oven takes longer time to cook food. 2. Open or loose wiring of magnetron filament
circuit. (Intermittent oscillation)
3. Aging change of magnetron
2. Loud buzzing noise can be heard. 1. Loose fan and fan motor
2. Loose screws on H.V. Transformer
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NE-1027 / NE-1037

9.2. NE-1037
CAUTION
1. Check grounding before checking for trouble.
2. Be careful of the high voltage circuit.
3. Discharge high voltage capacitor.
4. When checking the continuity of the switches or the high voltage transformer, disconnect one lead wire from these parts and then check
continuity with the AC plug removed. To do 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 by removed.
5. Do not touch any parts of the circuitry on the digital programmer circuit, since static electric discharge may damage this control panel.
Always touch yourself to ground while working on this panel to discharge any static charge in your body.
6. 230/240V AC is present at the shaded area of the digital programmer circuit (Terminals of power relay´s and primary circuit of low voltage
transformer). When troubleshooting, be cautious of possible electrical shock hazard.
First of all operate the microwave oven following the correct operating procedures in order to find the exact cause of any trouble.
9.2.1. [TROUBLE 1] Oven does not start cooking
SYMPTOM CAUSE CORRECTIONS
1. Oven is dead. 1. Open or loose lead wire harness
Fuses is OK. 2. Open thermal cutout (Magnetron) Check fan motor if thermal cutout is defective.
No display and no operation at all. 3. Open low voltage transformer
4. Defective DPC
2. Oven does not accept key input
(Program)
1. Key input is not in-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.
3. Oven lamp and fan motor turn on
when oven is plugged in with door
closed.
1. Misalignment or loose wiring of secondary latch
switch
Adjust door and latch switches.
2. Defective secondary latch switch
4. Timer starts count down but no
microwave oscillation.
1. Off-alignment of latch switches Adjust door and latch switches.
2. Defective primary latch switch
3. Open or loose wiring of power relay (RY1)
4. Defective power relay (RY1)
5. Defective DPC.
6. Open or loose connection of high voltage
circuit especially magnetron filament circuit
NOTE: Large contact resistance will bring lower
magnetron filament voltage and causing
magnetron to lower output and/or intermittent
oscillation.
7. Defective high voltage component
H.V. Transformer
H.V. Capacitor
H.V. Diode
Magnetron
Check high voltage component according to
component test procedure and replace if it is defective.
22
NE-1027 / NE-1037