Samsung M1874NR User manual

SRSC
SERVICE
MICROWAVE OVEN CONTENTS
MICROWAVE OVEN
1. Precaution
2. Specifications
3. Operating Instructions
4. Disassembly and Reassembly
5. Alignment and Adjustments
6. Troubleshooting
7. Exploded Views and Parts List
8. PCB Diagrams
9. Schematic Diagrams
Manual
M1874NR

PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
(a) Do not operate or allow the oven to be
operated with the door open.
(b) Make the following safety checks on
all ovens to be serviced before activating
the magnetron or other microwave
source, and make repairs as necessary:
(1) Interlock operation,
(2)properdoorclosing,
(3) seal and sealing surfaces (arcing,
wear, 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, and microwave generation
and transmission systems shall be
repaired, replaced, or adjusted by
procedures described in this manual
beforetheovenisreleasedtothe
owner.
(e) A Microwave leakage check to verify
compliance with the Federal
performance standard should be
performed on each oven prior to
release to the owner.

- 1 -
1. Precaution
Follow these special safety precautions. Although the microwave oven is completely safe during ordinary use,
repair work can be extremely hazardous due to possible exposure to microwave radiation, as well as potentially
lethal high voltages and currents.
1-1 Safety precautions ( )
1. All repairs should be done in accordance
with the procedures described in this
manual. This product complies with
Federal Performance Standard 21 CFR
Subchapter J(DHHS).
2. Microwave emission check should be
performed to prior to servicing if the oven is
operative.
3. If the oven operates with the door open :
Instruct the user not to operate the oven and
contact the manufacturer and the center for
devices and radiological health immediately.
4. Notify the Central Service Center if the
microwave leakage exceeds 5 mW/cm2.
5. Check all grounds.
6. Do not power the MWO from a "2-prong"
AC cord. Be sure that all of the built-in
protective devices are replaced. Restore any
missing protective shields.
7. When reinstalling the chassis and its
assemblies, be sure to restore all protective
devices, including: nonmetallic control
knobs and compartment covers.
8. Make sure that there are no cabinet openings
through which people --particularly
children --might insert objects and contact
dangerous voltages. Examples: Lamp hole,
ventilation slots.
9. Inform the manufacturer of any oven found
to have emission in excess of 5 mW/cm2,
Make repairs to bring the unit into
compliance at no cost to owner and try to
determine cause.
Instruct owner not to use oven until it has
been brought into compliance.
CENTRAL SERVICE CENTER
10. Service technicians should remove their
watches while repairing an MWO.
11. To avoid any possible radiation hazard,
replace parts in accordance with the wiring
diagram. Also, use only the exact
replacements for the following parts:
Primary and secondary interlock switches,
interlock monitor switch.
12. If the fuse is blown by the Interlock Monitor
Switch: Replace all of the following at the
same time: Primary, door sensing switch
and power relay, as well as the Interlock
Monitor Switch. The correct adjustment of
these switches is described elsewhere in
this manual. Make sure that the fuse has the
correct rating for the particular model being
repaired.
13. Design Alteration Warning:
Use exact replacement parts only, i.e.,
only those that are specified in the
drawings and parts lists of this manual.
This is especially important for the
Interlock switches, described above.
Never alter or add to the mechanical or
electrical design of the MWO. Any design
changes or additions will void the
manufacturer's warranty. Always unplug
the unit's AC power cord from the AC
power source before attempting to
remove or reinstall any component or
assembly.
14. Never defeat any of the B+ voltage
interlocks. Do not apply AC power to the
unit (or any of its assemblies) unless all
solid-state heat sinks are correctly installed.
15. Some semiconductor ("solid state") devices
are easily damaged by static electricity.
Such
components are called Electrostatically
Sensitive Devices (ESDs). Examples include
integrated circuits and field-effect
transistors.
Immediately before handling any
semiconductor components or assemblies,
drain the electrostatic charge from your
body by touching a known earth ground.
16. Always connect a test instrument's ground
lead to the instrument chassis ground before
connecting the positive lead; always remove
the instrument's ground lead last.

- 2 -
1-2 Special Servicing Precautions (Continued)
17. When checking the continuity of the witches
or transformer, always make sure that the
power is OFF, and one of the lead wires is
disconnected.
18. Components that are critical for safety are
indicated in the circuit diagram by
shading, or .
19. Use replacement components that have the
same ratings, especially for flame resistance
and dielectric strength specifications. A
replacement part that does not have the
same safety characteristics as the original
might create shock, fire or other hazards.
1-3 Special High Voltage Precautions
1. High Voltage Warning
Do not attempt to measure any of the high
voltages --this includes the filament voltage
of the magnetron. High voltage is present
during any cook cycle.
Before touching any components or wiring,
always unplug the oven and discharge the
high voltage capacitor (See Figure 1-1)
2. The high-voltage capacitor remains charged
about 30 seconds after disconnection. Short
the negative terminal of the high-voltage
capacitor to to the oven chassis. (Use a
screwdriver.)
3. High voltage is maintained within specified
limits by close-tolerance, safety-related
components and adjustments. If the high
voltage exceeds the specified limits, check
each of the special components.
PRECAUTION
There exists HIGH VOLTAGE ELECTRICITY
with high current capabilities in the circuits of the
HIGH VOLTAGE TRANSFORMER secondary
and filament terminals. It is extremely dangerous
to work on or near these circuits with the oven
energized.
DO NOT measure the voltage in the high voltage
circuit including filament voltage of magnetron.
PRECAUTION
Never touch any circuit wiring with your hand
nor with uninsulated tool during operation.
PRECAUTION
Servicemen should remove their watches
whenever working close to or replacing the
magnetron.
H.!V.!Diode
Short
H.!V.!Capacitor
Touch!chassis!ground!first!then!short!to!the!high
voltage!capacitor!terminal!by!using!screwdriver!or
jumper!wire.
!!
Fig.!1-1.!!Discharging!the!High!Voltage!Capacitor

- 3 -
2. Specifications
2-1 Table of Specifications
TIMER
POWER SOURCE
POWER CONSUMPTION
OUTPUT POWER
OPERATING FREQUENCY
MAGNETRON
COOLING METHOD
OUTSIDE DIMENSIONS
SHIPPING DIMENSIONS
OVEN DIMENSIONS
SHIPPING WEIGHT APPROX.
99 MINUTES
230V 50Hz, AC
MICROWAVE : 1,150W
FROM 100 TO 800W
(IEC-705 TEST PROCEDURE)
2,450MHz
OM75S(31)ESS
COOLING FAN MOTOR
489(W) x 275(H) x 370(D)mm
557(W) x 329(H) x 434(D)mm
306(E) x 211(H) x 320(D)mm
NET 14.0kg
GROSS 16.0kg

- 4 -
3. Operating Instructions
3-1 Control Panel
3-2 Features & External Views
Door
Ventilation!Holes Light Safety!Interlock!Hole
Control!Panel
Roller!Ring
Coupler
Glass!Plate
Door!Latches
+!30!s
1
2
3
4
5
/
342mm
275mm
370mm
206mm

- 5 -
4. Disassembly and Reassembly
4-1 Replacement of Magnetron, Motor Assembly and Lamp
Remove the magnetron including the shield case, permanent magnet, choke coils and capacitors (all of
whicharecontainedinoneassembly).
1. Disconnect all lead wires from the magnetron and lamp.
2. Remove a screw securing air cover.
3. Remove the air cover.
4. Remove screws securing the magnetron to the wave guide.
5. Take out the magnetron very carefully.
6. Remove nuts from the back panel.
7. Take out the fan motor.
8. Remove the oven lamp by rotating to pull out from hole of air cover.
NOTE1: When removing the magnetron, make sure that its antenna does not hit any adjacent
parts, or it may be damaged.
NOTE2: When replacing the magnetron, be sure to remount the magnetron gasket in the correct
positionandmakesurethegasketisingoodcondition.
4-2 Replacement of High Voltage Transformer
1. Discharge the high voltage capacitor.
2. Disconnect all the leads.
3. Remove the mounting bolts.
4. Reconnect the leads correctly and firmly.
PRECAUTION
Servicemen should remove their watches whenever
working close to or replacing the magnetron.
PRECAUTION
There exists HIGH VOLTAGE ELECTRICITY with high current capabilities in the circuits of the HIGH
VOLTAGE TRANSFORMER secondary and filament terminals. It is extremely dangerous to work on or near
these circuits with the oven energized.
DO NOT measure the voltage in the high voltage circuit including filament voltage of magnetron.

- 6 -
4-3 Replacement of Door Assembly
4-3-1 Removal of Door "C"
Insert flat screwdriver into the gap between Door
"A" and Door "C" to remove Door "C" . Be careful
when handling Door "C" because it is fragile.
Then remove the assembly.
4-3-2 Removal of Door "E"
Following the procedure as shown in the figure,
insert and bend a thin metal plate between Door
"E" and Door "A" until you hear the 'tick' sound.
1. Insertion depth of the thin metal plate should be
0.5mm or less.
4-3-3 Removal of Key Door & Spring
Remove pin hinge from Door "E"
Detach spring from Door "E" and key door.
Door "E"
Key Door Spring
Door "A"
Door "C"
Door "E"

- 7 -
4-3-4 Reassembly Test
1. 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.
2. 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 energy may leak from the space between the door and oven.
3. Do the microwave leakage test.
4-4 Replacement of Fuse
1. Disconnect the oven from the power source.
2. When 15A fuse blows out by the operation of interlock monitor switch failure, replace the primary interlock
switch, door sensing switch, monitor switch and power relay.
3. When the above three switches operate properly, check if any other part such as the control circuit board,
blower motor or high voltage transformer is defective.
4-5 Replacement of Drive Motor
1. Take out the glass tray, guide roller and coupler
from cavity.
2.Turntheovenupsidedowntoreplacethedrivemotor.
3. Remove a screw securing the drive motor cover.
4. Disconnect all the lead wires from the drive motor.
5. Remove screws securing the drive motor to the cavity.
6. Remove the drive motor.
7. When replacing the drive motor, be sure to
remount it in the correct position.
8. Connect all the leads to the drive motor.
9. Screw the drive motor cover to the base plate
with a screw driver.
10. Remount the coupler in the correct position.
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.
Drive!Motor!Cover Base!Plate
Drive!Motor

- 8 -
4-6 Replacement of Control Circuit Board
4-6-1 Removal of Ass'y Control Box
1. Be sure to ground any static electric charge
in your body and never touch the touch control
circuitry.
2. Disconnect the connectors from the control
circuit board.
3. Remove screws securing the control box
assembly.
4. Remove the screw securing the ground tail of
the keyboard.
4-6-2 Removal of Ass'y P.C.B
1. Remove screws securing the control circuit
board.
2. Lift up the control circuit board from the Ass'y
control box.
CONTROL BOX
SCREW
SCREW

- 9 -
5. Alignment and Adjustments
5-1 High Voltage Transformer
1. Remove connectors from the transformer terminals
and check continuity.
2. Normal resistance readings are as follows:
(Room temperature = 20∞C)
5-2 Low Voltage Transformer
1.Thelowvoltagetransformerislocatedonthe
control circuit board.
2. Remove the low voltage transformer from the
PCB Ass'y and check continuity.
3. Normal resistor reading is shown in the table.
5-3 Magnetron
1. Continuity checks can indicate only an open
filament or a shorted magnetron. To diagnose an
open filament or shorted magnetron :
2. Isolate the magnetron from the circuit by
disconnecting its leads.
3. A continuity check across the magnetron filament
terminals should indicate one ohm or less.
4. A continuity check between each filament terminal
and magnetron case should read open.
Terminals Resistance
1~2(Input)
3~4(Output 2.9V)
5~6(Output13V)
1,000.Ω.
3.947.Ω..
2.117.Ω.
Primary
Terminals
Filament Terminals
Secondary
Terminal
Magnetron Antenna Gasket Plate
Cooling Fins
PRECAUTION
1. High voltage is present at the high voltage terminals 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.
Secondary
Filament
Primary
Approx. 121Ω
Approx. 0Ω
Approx. 1.7Ω

- 10 -
5-4 High Voltage Capacitor
1. Check continuity of the capacitor with the meter set at the highest resistance scale.
2. Once the capacitor is charged, a normal capacitor shows continuity for a short time, and then indicates 9M.
3. A shorted capacitor will show continuous continuity.
4. An open capacitor will show constant 9M.
5. Resistance between each terminal and chassis should read infinite.
5-5 High Voltage Diode
1. Isolate the diode from the circuit by disconnecting its leads.
2. With the ohm-meter set at the highest resistance scale, measure across the diode terminals. Reverse the
meter leads and read the resistance. A 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). The resistance of a normal diode will be infinite in one direction and several hundred Kin the
other direction.
5-6 Main Relay and Power Control Relay
1. The relays are located on the PCB Ass'y. Isolate them from the main circuit by disconnecting the leads.
2. Operate the microwave oven with a water load in the oven. Set the power level set to high.
3. Check continuity between terminals of the relays after the start pad is pressed.
5-7 Adjustment of Primary Switch, Door Sensing Switch and Monitor Switch
1. When mounting Primary switch and Interlock
Monitor switch to Latch Body, consult the figure.
2. No specific adjustment during installation of
Primary switch and Monitor switch to the latch
body is necessary.
3. When mounting the Latch Body to the oven
assembly, adjust the Latch Body by moving it 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 Latch
Body to the oven assembly.
4. Reconnect to Monitor switch and check the
continuity of the monitor circuit and all latch
switches again by following the components test
procedures.
5. Confirm that the gap between the switch
housingandtheswitchactuatorisnomorethan
0.5mm when door is closed.
6. Interlock Switch Replacement - When
replacing faulty switches, be sure switch mounting
tabs are not bent, broken or otherwise deficient in
their ability to secure the switches in place.
Door Open Door Closed
Primary switch
Monitor switch(COM-NC)
Monitor switch(COM-NO)
Door Sensing S/W
∞
0
∞
∞
0
∞
0
0
Precaution
For continued protection against radiation hazard, replace parts in accordance with the wiring diagram and be sure to
use the correct part number for the following switches: Primary and secondary interlock switches, and the interlock
monitor switch (replace all together). Then follow the adjustment procedures below. After repair and adjustment, be
sure to check the continuity of all interlock switches and the interlock monitor switch.
Lever Door(B)
Interlock
Monitor
Switch
Primary Interlock Switch
Body Latch
Lever Door(A)
Door Sensing
Switch

- 11 -
5-8 Output Power of Magnetron
The output power of the magnetron can be measured by performing a water temperature rise test.
Equipment needed :
* Two 1-liter cylindrical borosilicate glass vessel (Outside diameter 190 mm)
* One glass thermometer with mercury column
NOTE: Check line voltage under load. Low voltage will lower the magnetron output. Make all temperature
and time tests with accurate equipment.
1. Fill the one liter glass vessel with water.
2. Stir water in glass vessel with thermometer, and record glass vessel's temperature ("T1", 10±1∞C).
3. After moving the water into another glass vessel, place it in the center of the cooking tray. Set the oven to
high power and operate for 55seconds exactly. (3 seconds included as a holding time of magnetron
oscillation:)
4. When heating is finished, stir the water again with the thermometer and measure the temperature ("T2").
5. Subtract T1 from T2. This will give you the water temperature rise. (△T)
6. The output power is obtained by the following formula;
Output Power = 4.187 x 1000 x △T+0.55xMcx(T2-T0) 55:HeatingTime(sec)
52 52 : Counting Time (sec)
4.187 : Coefficient for Water
1000 : Water (cc)
△T : Temperature Rise (T2-T1)
To : Room Temperature
Mc : Cylindrical borosilicate glass weight
7. Normal temperature rise for this model is 9∞Cto11∞Cat'HIGH'.
NOTE 1: Variations or errors in the test procedure will cause a variance in the temperature rise.
Additional power test should be made if temperature rise is marginal.
NOTE 2: Output power in watts is computed by multiplying the temperature rise (step E) by a factor of 91
times the of centigrade temperature.
5-9 Microwave Heat Distribution - Heat Evenness
The microwave heat distribution can be checked indirectly by measuring the water temperature rise at
certain positions in the oven:
1. Prepare five beakers made of 'Pyrex', having 100 milliliters capacity each.
2. Measure exactly 100milliliters off water load with a measuring cylinder, and pour into each beaker.
3. Measure the temperature of each water load. (Readings shall be taken to the first place of decimals.)
4. Put each beaker in place on the cooking tray as illustrated in figure below. Start heating.
5. After heating for 2 minutes, measure the water temperature in each beaker.
6. Microwave heat distribution rate can be calculated as follows:
Minimum
Heat Distribution = Temperature Rise X 100(%)
Maximum
Temperature Rise
The result should exceed 65%
CAUTION
MICROWAVE RADIATION
PERSONNEL SHOULD NOT ALLOW EXPOSURE TO MICROWAVE RADIATION FROM MICROWAVE
GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker
D
D
D/4
D/4
D/4
D/4
Cooking!Tray
Beaker

- 12 -
5-10 Procedure for Measurement of Microwave Energy Leakage
1) Pour 275±15cc of 20±5∞C(68±9∞F) water in a beaker
which is graduated to 600cc, and place the beaker in
the center of the oven.
2) Start to operate the oven and measure the leakage by
using a microwave energy survey meter.
3) Set survey meter with dual ranges to 2,450MHz.
4) When measuring the leakage, always use the 2 inch
spacer cone with the probe. Hold the probe
perpendicular to the cabinet door. Place the spacer
cone of the probe on the door and/or cabinet door
seam and move along the seam, the door viewing
window and the exhaust openings moving the
probe in a clockwise direction at a rate of 1 inch/sec. If the leakage testing of the cabinet door seam is
taken near a corner of the door, keep the probe perpendicular to the areas making sure that the probe end
at the base of the cone does not get closer than 5cm to any metal. If it gets closer than 5cm, erroneous
readings may result.
5) Measured leakage must be less than 4mW/cm2,after repair or adjustment.
5-11 Check for Microwave Leakage
1. Remove the outer panel.
2. Pour 275±15cc of 20±5∞C(68±9∞F) water in a beaker
which is graduated to 600cc, and place the beaker in
the center of the oven.
3. Start the oven at the highest power level.
4. Set survey meter dual ranges to 2,450MHz.
5. Using the survey meter and spacer cone as described
above, measure near the opening of magnetron, the
surface of the air guide and the surface of the wave
guide as shown in the following photo.( but avoid the
high voltage components.) The reading should be less than 4mW/cm2.
5-12 Note on Measurement
1) Do not exceed the limited scale.
2) The test probe must be held on the grip of the handle, otherwise a false reading may result when the
operator's hand is between the handle and the probe.
3) When high leakage is suspected, do not move the probe horizontally along the oven surface; this may
cause damage to the probe.
4) Follow the recommendation of the manufacturer of the microwave energy survey meter.
5-12 Leakage Measuring Procedure
5-12-1 Record keeping and notification after measurement
1) After adjustment and repair of a radiation preventing device, make a repair record for the measured
values, and keep the data.
2) If the radiation leakage is more than 4 mW/cm2after determining that all parts are in good condition,
functioning properly and the identical parts are replaced as listed in this manual notify that fact to ;
CENTRAL SERVICE CENTER
5-12-2 At least once a year have the microwave energy survey meter checked for accuracy by its
manufacturer.
Maximum allowable leakage is 5mW/cm2.
4mW/cm2is used to allow for measurement and meter accuracy

- 13 -
6. Troubleshooting
6-1 Electrical Malfunction
SYMPTOM CAUSE CORRECTIONS
Oven is dead.
Fuse is OK.
No display and no operation at all .
1. Open or loose lead wire harness
2. Open thermal cutout (Magnetron)
3. Open low voltage transformer
4. Defective Ass'y PCB
Check fan motor when thermal
cutout is defective.
Check Ass'y PCB when L.V.T is
defective.
No display and no operation at all.
Fuse is blown.
1. Shorted lead wire harness
2. Defective primary latch switch
(NOTE 1)
3. Defective monitor switch (NOTE1)
4. Shorted H.V.Capacitor
5. Shorted H.V.Transformer (NOTE2)
Check adjustment of primary,
interlock monitor,
power relay, door sensing switch.
NOTE 1: All of these switches must be replaced at the same time.
(refer to adjustment instructions)
Check continuity of power relay contacts and if it has
continuity, replace power relay also.
NOTE 2: When H.V.Transformer is replaced, check diode and
magnetron also.
Oven does not accept
key input (Program)
1. Key input is not in-Sequence
2. Open or loose connection of
membrane key pad to Ass'y PCB
3. Shorted or open membrane panel
4. Defective Ass'y PCB
Refer to operation procedure.
Replace PCB main.
Timer starts countdown but no
microwave oscillation.
(No heat while oven lamp and fan
motor turn on.)
1. Off-alignment of latch switches
2. Open or loose connection of high
voltage circuit especially
magnetron filament circuit
NOTE: Large contact resistance will
bring lower magnetron
filament voltage and cause
magnetron to lower output
and/or intermittent oscillation.
3. Defective high voltage
components H.V.Transformer H.V.
Capacitor H.V.Diode, H.V.Fuse
Magnetron
4. Open or loose wiring of power relay
5. Defective primary latch switch
6. Defective power relay or Ass'y PCB
Adjust door and latch switches.
Check high voltage component
according to
component test procedure and
replace if it is
defective.
Replace PCB main.
PRECAUTION
1. CHECK GROUNDING BEFORE CHECKING FOR TROUBLE.
2. BE CAREFUL OF THE HIGH VOLTAGE CIRCUIT.
3. DISCHARGE THE HIGH VOLTAGE CAPACITOR.
4. WHEN CHECKING THE CONTINUITY OF THE SWITCHES OR TRANSFORMER, DISCONNECT
ONE LEAD WIRE FROM THESE PARTS AND THEN CHECK CONTINUITY WITHOUT THE
POWER SOURCE ON. TO DO OTHERWISE MAY RESULT IN A FALSE READING OR DAMAGE
TO YOUR METER.
5. DO NOT TOUCH ANY PART OF THE CIRCUIT OR THE CONTROL CIRCUIT BOARD, SINCE
STATIC DISCHARGE MAY DAMAGE IT.
ALWAYS TOUCH GROUND WHILE WORKING ON IT TO DISCHARGE ANY STATIC CHARGE
BUILT UP.

- 14 -
6-1 Electrical Maltunction(continved)
SYMPTOM CAUSE CORRECTIONS
Oven lamp and fan motor turn on 1. Misadjustment or loose wiring
of primary latch switch
2. Defective primary latch switch
Adjust door and latch switches.
Oven can program but timer
does not start.
1. Open or loose wiring of
secondary interlock switch
2. Off-alignment of primary
interlock
3.
Defective secondary interlock S/W
Adjust door and interlock switches.
Microwave output is low;.
Oven takes longer time to
cook food.
1. Decrease in power source
voltage.
2. Open or loose wiring of
magnetron filament circuit.
(Intermittent oscillation))
3. Aging of magnetron
Consult electrician.
Fan motor turns on when plugged
in Loose wiring of door sensing switch Check wire of door sensing switch.
Oven does not operate and return
to the plugged in mode.
Defective Ass'y PCB Replace PCB main.
Loud buzzing noise can be heard. 1. Loose fan and fan motor
2. Loose screws on
H.V.Transformer
3. Shorted H.V.Diode
Tighten screws of fan motor.
Tighten screws of
H.V.Transformer.
Replace H.V.Diode.
Turntable motor does not rotate. 1. Open or loose wiring of
turntable motor.
2. Defective turntable motor.
Replace turntable motor.
Oven stops operation during
cooking
1. Open or loose wiring of primary
interlock switch
2. Operation of thermal
cutout(Magnetron)
Adjust door and latch switches.
Sparks 1. Metallic ware or cooking dishes
touching on the oven wall.
2. Ceramic ware trimmed with
gold or silver powder also
causes sparks.
Inform the customer.
Do not use any type of cookware
with
metallic trimming.
Uneven cooking Uneven intensity of microwave due to
its characteristics.
Wrap thinner parts of the food
with aluminum foil.
Use plastic wrap or cover with a
lid.
Stir once or twice while cooking
foods such as soup, cocoa, or
milk.
Noise from the turntable motor
when it starts to operate.
Noise may result from the motor. Replace turntable motor.

- 15 -
7. Exploded Views and Parts List
7-1 Exploded Views
MM01
MM28
MM07
MM16
MM03
MM14
MM09!!!!!!!!!!
MM30
MM31
MM32
MM27
MM55
MM22
MM88
MM05
MM26
MM06
MM17
MM08
MM10
MM19
MM20
MM18
MM29
MC01
MD14
MD02
MD03
MD04
MD07
MD10
MD06
MD24
MC141
MC17
MC04
MC27
MC03
MC15
MC142
MC23
MC07
MC41
MC10
MC13
MC06
MD01
MD05
MD11
MB01
MB05
MB03
MB02
MB042
MB041

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7-2 Main Parts List
No. Code No. Description Specification Q'ty Remark
MB01 DE96-00120B ASSY BODY LATCH M1717N,NC2000(HANDLE) 1
MB02 3405-000175 SWITCH-MICRO 250V,15A,200gf,SPST-NO 1
MB03 3405-000178 SWITCH-MICRO 250V,15A,200gf,SPST-NO 2
MB041 DE66-00093A LEVER-SWITCH(A) NC2000,PP-TH53,-,-,-,-,NTR,HANDLE 1
MB042 DE66-00094A LEVER-SWITCH(B) NC2000,PP-TH53,-,-,-,-,NTR,HANDLE 1
MB05 DE72-00137A BODY-LATCH NC2000(0.6/0.8/1.2),PP,-,-,-,-,WHT,- 1
MM01 DE70-00184P PANEL-OUTER MW850WA,C/STEEL,T0.5,P/WHT,- 1
MM03 DE39-00147C WIRE HARNESS-A M1733N,-,-,230V50HZ,-,-,-,-,NC2000 1
MM05 DE96-00010A ASSY NOISE FILTER SN-3WED,250V10A,3W NO-INRUSH TC,- 1
MM06 DE96-00031A ASSY-MOTOR FAN SMF-3RDEA,230V50HZ,2400RPM,M1733,- 1
MM07 DE39-00224A ASSY POWER CORD M308,-,KDK-4819D,250V6A,0.75mm/3C,- 1
MM08 OM75S(31)ESS ASSY-MAGNETRON:OM75S 1
MM09 DE71-60457B COVER-AIR 3RD-0.7(BTM),PP,-,-,-,-,-,- 1
MM10 4713-001031 LAMP-INCANDESCENT 230V,173mA,40W,ORG,-,-,25x69mm 1
MM14 DE26-00059A TRANS-H.V SHV-E1713A,230V,50HZ,2130V/3.65V,-,-,-,- 1
MM16 DE71-00151A COVER-MGT MW850WA,PP,T2,W54,L129,-,GE-WHT,NC2000 1
MM17 DE47-20173A THERMOSTAT PW-2N(90/60)30,187Y,250V7.5A,9 1
MM18 DE74-20102B TRAY-COOKING GLASS,T5.0,M745,-,- 1
MM19 DE97-00193B ASSY-GUIDE ROLLER NC2000 0.6,T2*P1198(14PI),-,- 1
MM20 DE67-00140A COUPLER NC2000(0.6~0.8),PPS(ESS840),-,3G,BRN,NEW 1
MM22 DE31-10154A MOTOR-SYNCHRONOUS M2HJ49ZR02,ST-16,50/60HZ,- 1
MM26 DE71-00148A COVER-BLOWER MW850WA,PP,T1.5,-,-,-,NTR,NC2000(0.8CUFT) 1
MM27 DE61-40066A FOOT -,PP,-,BLK,-,-,- 2
MM28 DE80-00023A BASE-PLATE MW850WA,SGCC1,T0.6,-,-,NC2000,0.8CUFT 1
MM29 2501-001016 C-OIL 950nF,2.1KV,BK,35x54x80,20mm 1
MM30 DE61-00139A BRACKET-HVC NC2000,SECC,T0.8,-,-,-,0.6/0.8/1.2CUFT 1
MM31 DE59-00002A DIODE-H.V ESJC13-12B,12KV,-,-,-,MWO ALL,- 1
MM32 DE91-70061C ASSY-H.V.FUSE THV060T-0700-H,5KV/0.70A,BLU 1
MM55 3601-000448 FUSE-CARTRIDGE 250V,10A,SLOW-BLOW,CERAMIC,6.35x31.8mm 1
MM88 DE73-90027B FERRITE RU65(RU15*28.6*6.5),-,M2L(FE2O3+Ni+Zn) ,-,-,- 1

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7-3 Control & Door Parts List
No. Code No. Description Specification Q'ty Remark
MC01 -ASSY CONTROL-BOX -,M1874NR/BWT,PURE-WHT,CIS 1S.N.A
MC03 DE72-00115J CONTROL-PANEL M1874NR/BWT,ABS,-,-,-,-,PURE-WHT,CIS,FISH 1
MC04 DE61-70135A SPRING-BUTTON PI0.6,BUTTON-SELECT(C),BUTTON-SELECT(C),- 1
MC06 DE67-00003B WINDOW-DISPLAY M1774,ACRYL,-,-,-,-,SMOG,- 1
MC07 RC-22F207-07 ASSY PCB PARTS M1774NR,230V50Hz 1
MC10 DE64-00079A KNOB-DIAL M1974,ABS(HR0370),-,-,-,-,-,-,PCB-1BD 1
MC13 DE94-00389H ASSY CONTROL-PANEL -,M1874NR/BWT,PURE-WHT,CIS 1
MC141 DE67-00038J BUTTON-SELECT(A) M1774R-1/BWT,-,-,-,-,NEW 1
MC142 DE67-00035A BUTTON-SELECT(B) M1774,-,-,-,-,- 1
MC15 DE64-00110A BUTTON-START M1774-1,ABS,-,-,P/WHT,- 1
MC17 DE71-00005R COVER-PANEL M1774R/BWT,ABS(HR0370),-,-,-,-,-,M1774R/BWT 1
MC23 DE67-00036A BUTTON-CLOCK M1774,-,-,-,-,- 1
MC27 DE67-00037A BUTTON-CANCEL M1774,-,-,-,-,- 1
MC41 DE63-00016A CUSHION-PCB M1774-1,PUT-FOAM,PUT-FOAM,T20,W85.5,L50,- 1
MD01 -ASSY DOOR M1814NR/M1874NR/BWT,PURE-WHT,CIS,FISH 1S,N,A
MD02 DE64-40277B DOOR-A FISH,ABS(HR-0370),M759/M759R,-,-,-,WHT(W9501),- 1
MD03 DE64-40278K SCREEN-DOOR ACRYL,-,-,-,SMOG,M1714R/BWT,RUSSIA 1
MD04 DE92-50133C ASSY DOOR-E MW4593G,-,BLK,3RD-0.7,-,-,- 1
MD05 DE01-00112A FILM-DOOR -,PET,-,L268,T0.15,W150,NTR,-,- 1
MD06 DE64-40008B DOOR-C -,PP,CE745G,-,-,-,BLK,- 1
MD07 DE61-00198A SPRING-KEY M1877,HSWR,D6,-,-,23 1/4,23 1/4,T0.7,BLUING,- 1
MD10 DE64-00264A DOOR-KEY 3RD-W NEW,POM,-,BLK,-,-,- 1
MD11 DE94-00124B ASSY DOOR-SUB MW4593G,BLK,3RD-0.7,-,-,-,- 1
MD14 DE64-20116B HANDLE-DOOR M1774,3RD-FISH2,ABS,-,-,-,-,P/WHT,- 1
MD24 DE94-00202F ASSY DOOR-A M1714R/BWT,P-WHT,FISH2,SUB-PART,-,-,-,- 1
S.N.A : SERVICE NOT AVAILABLE

- 18 -
7-4 Standard Parts List
Code No. Description Specification Q'ty Remark
DE60-10012A SCREW-TAP TITE -,SWR10,M4,L10,TH,+,-,3,ZPC2,- 1N/P EARTH
DE60-10012A SCREW-TAP TITE -,SWR10,M4,L10,TH,+,-,3,ZPC2,- 1P/C EARTH
DE60-10012A SCREW-TAP TITE -,SWR10,M4,L10,TH,+,-,3,ZPC2,- 1PCB EARTH
DE60-10012A SCREW-TAP TITE -,SWR10,M4,L10,TH,+,-,3,ZPC2,- 1TCO-S/W
DE60-10063A SCREW-TAP TH -,-,FEFN,-,TH,M4,-,L12,-,- 1O/PANEL
DE60-10080B SCREW-WASHER -,2S,SWRCH18A,ZP2,PH,PI5,-,L10,-,- 4HVT
DE60-10080B SCREW-WASHER -,2S,SWRCH18A,ZP2,PH,PI5,-,L10,-,- 4MGT
DE60-10082H SCREW-A -,-,-,-,2S-4X12,TOOTHED,-,-,-,- 1AIR/COVER
DE60-10082H SCREW-A -,-,-,-,2S-4X12,TOOTHED,-,-,-,- 2B/LATCH
DE60-10082H SCREW-A -,-,-,-,2S-4X12,TOOTHED,-,-,-,- 3B/PLATE
DE60-10082H SCREW-A -,-,-,-,2S-4X12,TOOTHED,-,-,-,- 1C/BLOWER
DE60-10082H SCREW-A -,-,-,-,2S-4X12,TOOTHED,-,-,-,- 1C/BOX
DE60-10082H SCREW-A -,-,-,-,2S-4X12,TOOTHED,-,-,-,- 4O/PANEL
DE60-10098A SCREW-ASSY TAP TITE -,GLD,SWRCH18A,ZPC2,PH,TC,-,M4X8,WT,- 1D/MOTOR
DE60-30016A NUT-FLANGE M4,MSWR10,-,-,-,-,-,-,- 2F-MOTOR
DE60-10069A SCREW-TAP TH -,-,FRFZY,-,TH,M4,-,L10,-,- 2SCR/DOOR
DE60-10088A SCREW-TAP PH -,-,FEFZY,PLAIN,PH,M3,-,L8,-,- 6PCB
DE60-10012A SCREW-TAP TITE -,SWR10,M4,L10,TH,+,-,3,ZPC2,- 1B/COVER
DE60-10098A SCREW-ASSY TAP TITE -,GLD,SWRCH18A,ZPC2,PH,TC,-,M4X8,WT,- 1HVD