Daewoo | KOC-970T1S | Service manual | Daewoo KOC-970T1S Service manual

Daewoo KOC-970T1S Service manual
S/M No. : G867T9A001
Service Manual
Microwave Oven & Grill
Model : KQG-1N1AS
• Caution:
In this Manual, some parts can be changed for improving,
their performance without notice in the parts list. So, if you
need the latest parts information, please refer to PPL(Parts
Price List) in Service Information Center (http://svc.dwe.co.kr).
Oct. 2009
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 if necessary: (1) Interlock operation, (2) Proper door closing, (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 power to the microwave oven 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 before the oven is released to the 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.
TABLE OF CONTENTS
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO
EXCESSIVE MICROWAE ENERGY................................................................................................................................1
SAFETY AND PRECAUTIONS........................................................................................................................................2
FOR SAFE OPERATION...............................................................................................................................................2
FOR SAFE SERVICE PROCEDURES .........................................................................................................................2
SPECIFICATIONS ............................................................................................................................................................3
EXTERNAL VIEW .............................................................................................................................................................4
OUTER DIMENSION .....................................................................................................................................................4
FEATURE DIAGRAM.....................................................................................................................................................5
CONTROL PANEL.........................................................................................................................................................6
INSTALLATION ................................................................................................................................................................7
OPERATIONS AND FUNCTIONS ...................................................................................................................................8
DISASSEMBLY AND ASSMBLY.....................................................................................................................................9
INTERLOCK MECHANISM AND ADJUSTMENT.........................................................................................................18
TROUBLESHOOTING GUIDE .......................................................................................................................................19
MESUREMENT AND TEST............................................................................................................................................23
MEASUREMENT OF THE MICROWAVE POWER OUTPUT ...................................................................................23
MICROWAVE RADIATION TEST ...............................................................................................................................24
COMPONENT TEST PROCEDURE ...........................................................................................................................25
WIRING DIAGRAM.........................................................................................................................................................26
PRINTED CIRCUIT BOARD...........................................................................................................................................27
CIRCUIT CHECK PROCEDURE.................................................................................................................................27
PCB CIRCUIT DIAGRAM ............................................................................................................................................30
P.C.B. LOCATION NO. ................................................................................................................................................31
EXPLODED VIEW AND PARTS LIST ...........................................................................................................................32
DOOR ASSEMBLY ......................................................................................................................................................32
CONTROL PANEL ASSEMBLY..................................................................................................................................32
TOTAL ASSEMBLY .....................................................................................................................................................32
1
SAFETY AND PRECAUTIONS
CAUTION : This Device is to be Serviced Only by Properly Qualified Service Personnel. Consult the Service
Manual for Proper Service Procedures to Assure Continued Safety Operation and for Precautions
to be Taken to Avoid Possible Exposure to Excessive Microwave Energy.
1. FOR SAFE OPERATION
Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and
may cause serious bodily injury to the operator.
IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST NOT USE THE APPLIANCE.
(Only a trained service personnel should make repairs.)
1) A broken door hinge.
2) A broken door viewing screen.
3) A broken front panel, oven cavity.
4) A loosened door lock.
5) A broken door lock.
The door gasket plate and oven cavity surface should be kept clean.
No grease, soil or spatter should be allowed to build up on these surfaces or inside the oven.
DO NOT ATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOR OPEN. The microwave oven has
concealed switches to make sure the power is turned off when the door is opened. Do not attempt to defeat them.
DO NOT ATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.
2. FOR SAFE SERVICE PROCEDURES
1) If the oven is operative prior to servicing, a microwave emission check should be performed prior to servicing
the oven.
2) If any certified oven unit is found to servicing, a microwave emission check should be performed prior to
servicing the oven.
(a) inform the manufacturer, importer or assembler,
(b) repair the unit at no cost to the owner,
(c) attempt to ascertain the cause of the excessive leakage,
(d) tell the owner of the unit not to use the unit until the oven has been brought into compliance.
3) If the oven operates with the door open, the service person should tell the user not to operate the oven and
contact the manufacturer and CDRH immediately.
CAUTION
MICROWAVE RADIATION
PERSONNEL SHOULD NOT BE EXPOSED TO THE MICROWAVE ENERGY WHICH MAY RADIATE FROM
THE MAGNETRON OR OTHER MICROWAVE GENERATING DEVICE IF IT IS IMPROPERLY USED OR
CONNECTED. ALL INPUT AND OUTPUT MICROWAVE CONNECTIONS. WAVEGUIDES FLANGES AND
GASKETS MUST BE SECURED. NEVER OPERATE THE DEVICE WITHOUT A MICROWAVE ENERGY
ABSORBING LOAD ATTACHED. NEVER LOOK INTO AN OPEN WAVEGUIDE OR ANTENNA WHILE THE
DEVICE IS ENERGIZED.
2
SPECIFICATIONS
MODEL
KQG-1N1A9A52
POWER SUPPLY
120V~60HZ, SINGLE PHASE WITH EARTHING
POWER
MICROWAVE
1500 W
CONSUMPTION
GRILL
1050 W
MICROWAVE ENERGY OUTPUT
1000 W
MICROWAVE FREQUENCY
2450MHz
OUTSIDE DIMENSIONS (W X H X D)
515 x 304 x 375 mm (20.3 x 12.0 x 14.8 in.)
CAVITY DIMENSIONS (W X H X D)
356 x 239 x 358 mm(14.0 x 9.4 x 14.1 in.)
NET WEIGHT
APPROX. 13.2 kg (29.1lbs)
TIMER
59min. 99sec.
FUNCTION SELECTIONS
MICROWAVE, GRILL
POWER SELECTIONS
10 LEVELS
CAVITY VOLUME
1.1 Cu.Ft
* Specifications are subject to change without notice.
EXTERNAL VIEW
1. OUTER DIMENSION
14.8
12.0
20.3
3
2. FEATURES DIAGRAM
1
2
3
45
6
7
w
q
0 9
8
e
1 Door latch - When the door is closed, it will
automatically shut off. If the door is opened while
the oven is operating, the magnetron will
automatically shut off.
8 Waveguide cover - Protects the microwave outlet
from splashes of cooking foods.
9 Roller guide - This must always be used for
cooking together with the glass cooking tray.
2 Door seal - The door seal surfaces prevent
microwaves escaping from the oven cavity.
0 Coupler - This fits over the shaft in the center of
the oven cavity floor. This is to remain in the oven
for all cooking.
3 Oven cavity
4 Oven lamp - Automatically turns on during oven
operating.
q Glass cooking tray - Made of special heat
resistant glass. The tray must always be in proper
position before operating. Do not cook food directly
on the tray.
5 Safety interlock system
6 Control panel
w Viewing screen - Allows viewing of food. The
screen is designed so that light can pass through,
but not the microwave.
7 Door open button - To open the door push the
door open button.
e Metal Rack
5
3. CONTROL PANEL
r
M/W
Def .
Grill
Timer/g
AUTO COOK
a
o
1.
2.
3.
4.
5.
Bread
Soup
Baked potato
Fresh Vegetable
Frozen vegetable
Auto
Cook
Dinner
Plate
Frozen
Pizza
Popcorn
Beverage
o
Meat
Poultry
Fish
p
s
Power
Grill
Defrost
i
AUTO DEFROST
u
y
t
Kitchen
Timer
f
Clock
g
d
h
Stop
Start
Clear
speedy start
j
r Display-Cooking time, power level, indicators and
present time are displayed.
s Auto Defrost-Used to defrost foods.
(for weight)
t Auto Cook-Used to cook or reheat.
d Time set pad-Used to set the cooking time
and the present time.
y Grill-Used to cook GRILL.
f Kitchen Timer-Used as a minute timer, to delay
the start of cooking, or to set a holding time after
cooking.
u POWER-Used to set power level.
i Defrost-Used to defrost foods.(for time)
g Clock-Used to set clock.
o One touch-Used to cook or reheat specific
quantities of food.
h Stop/Clear-Used to stop the oven operation or to
delete the cooking data.
p Less-Used to remove time from cooking.
j Start/speedy start-Used to start the oven
and also used to set a reheat time.
a More-Used to add time to cooking.
6
INSTALLATION
1. Steady, flat location
This microwave oven should be set on a steady, flat surface.
This microwave oven is designed for counter top use only.
2. Leave space behind and side
All air vents should be kept a clearance. If all vents are covered during operation, the oven may overheat and, eventually,
cause oven failure.
3. Away from Radio and TV sets
Poor television reception and radio interference may result if the oven is located close to a TV, Radio, antenna or feeder
and so on.
4. Away from heating appliances and water taps
Keep the oven away from hot air, steam or splash when choosing a place to position it, or the insulation might be
adversely affected and breakdowns occur.
5. Power supply
Check your local power source.
This microwave oven requires a current of approximately 13 amperes, 120 Volts, 60 Hz grounded outlet.
Power supply cord is about 0.8 meters long.
1) A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or tripping over a
longer cord.
2) Longer cord sets or extension cords are available and may be used if care is exercised in their use.
3) If a long cord or extension cord is used:
1 The marked electrical rating of the cord set or extension cord should be at least as great as the electrical rating of
the appliance.
2 The extension cord must be a grounding type 3-wire cord.
3 The longer cord should be arranged so that it will not drape over the counter top or tabletop where it can be pulled
on by children or tripped over unintentionally.
6. Examine the oven after unpacking for any damage such as:
A misaligned door, broken door or a dent in cavity.
If any of the above are visible, DO NOT INSTALL, and notify dealer immediately.
7
OPERATIONS AND FUNCTIONS
1. Connect the main lead to an electrical outlet.
2. After placing the food in a suitable container, open the oven door and put it on the glass tray. The glass tray must
always be in place during cooking.
3. Close the door securely.
4. When the oven door is opened, the light turns on.
5. The oven door can be opened at any time during operation by touching the door release button on the control panel.
The oven will automatically shut off. To restart the oven, close the door and then touch START.
6. Each time a pad is touched, a BEEP will sound to acknowledge the touch.
7. The oven automatically cook on full power unless set to a lower power level.
8. The display will show : 0 when the oven is plugged in.
9. Time clock returns to the present time when the cooking time ends.
10. When the STOP/CLEAR pad is touched during the oven operation, the oven stops cooking and all information
retained.
To erase all information (except the present time), touch the STOP/CLEAR pad once more. If the oven door is
opened during the oven operation, all information is retained.
11. If the START pad is touched and the oven does not operate, check area between the door and door is closed
securely. The oven will not start cooking under the door is completely closed or the program has been reset.
12. When using the GRILL mode ;
• Do not open the door so often, the temperature inside the oven decrease and the cooking may not be completed
in setting time.
• Never touch the oven window and metal interior of the oven when taking food in and out, because the
temperature inside the oven and door is very high.
• When using these modes, be careful as the tray will be hot to touch, use oven gloves or pot holders while
handing tray.
Make sure the oven is properly installed and plugged into the electrical outlet.
Wattage output chart
The power level is set by pressing the POWER pad. The chart shows the display, the power level and the percentage
of power.
Touch POWER pad.
Power level(Display)
Approximate Percentage of Power
Once
P-HI
100%
Twice
P-90
90%
3 times
P-80
80%
4 times
P-70
70%
5 times
P-60
60%
6 times
P-50
50%
7 times
P-40
40%
8 times
P-30
30%
9 times
P-20
20%
10 times
P-10
10%
11 times
P-00
0%
8
DISASSEMBLY AND ASSEMBLY
Cautions to be observed when trouble shooting.
Unlike many other appliances, the microwave oven is high-voltage, high-current equipment. It is completely safe
during normal operation. However, carelessness in servicing the oven can result in an electric shock or possible
danger from a short circuit. You are asked to observe the following precautions carefully.
1. Always remove the power plug from the outlet before servicing.
2. Use an insulated screwdriver and wear rubber gloves when servicing the high voltage side.
3. Discharge the high voltage capacitor before touching any oven components or wiring.
(1) Check the grounding.
Do not operate on a two-wire extension cord.
The microwave oven is designed to be used while grounded.
It is imperative, therefore, to make sure it is grounded
properly before beginning repair work.
(2) Warning about the electric charge in the high voltage capacitor.
For about 30 seconds after the operation has stopped, electric
charge remains in the high voltage capacitor.
When replacing or checking parts, short between oven chassis
and the negative high terminal of the high voltage capacitor by
using a properly insulated screwdriver to discharge.
4. When the 20A fuse is blown due to the operation of the monitor
switch; replace primary interlock switch, secondary interlock switch
and interlock monitor switch.
5. After repair or replacement of parts, make sure that the screws are
properly tightened, and all electrical connections are tightened.
6. Do not operate without cabinet.
CAUTION : Service personnel should remove their watches whenever working close to or replacing the magnetron.
WARNING : When servicing the appliance, take care when touching or replacing high potential parts because of
electrical shock or exposing microwave. These parts are as follows - HV Transformer, Magnetron,
HV Capacitor, HV Diode, HV Fuse.
9
1. To remove cabinet
1) Remove three screws on cabinet back.
2) Push the cabinet backward.
2. To remove door assembly
1) Remove two screws which secure the stopper hinge top.
2) Remove the door assembly from top plate of cavity.
3) Reverse the above for reassembly.
NOTE : After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.
10
3. To remove door parts.
DOOR ASSEMBLY : 3511727430
REF. NO
PART CODE
PART NAME
DESCRIPTION
A01
3517010820
BARRIER-SCREEN*O
TEMP GLASS T3.2 MIRROR
1
A02
3512210550
FRAME DOOR
KOR-1N1A SILVER SPRAY
1
A03
3515204120
STOPPER HINGE*T
AS KOR-6L0B1A
1
A04
3511727500
DOOR PAINTING
AS KOR-1N0A9A
1
A05
3517006000
BARRIER-SCREEN*I
PE T1.0
1
A06
3512301330
GASKET DOOR
PP
1
A07
3513100700
HOOK
POM
1
A08
3515101900
SPRING HOOK
PW-1
1
(1) Remove the gasket door from the door painting as.
(2) Remove the barrier screen*i from the door painting as.
(3) Remove the door sub as from the door painting as.
(4) Remove the stopper hinge top from the door painting as.
(5) Remove the spring and the hook.
(6) Remove the barrier screen*o from the door sub as.
(7) Reverse the above steps for reassembly.
11
Q'TY
REMARK
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part ‘A’
• Loosen two screws on the stopper hinge top, and then
push the door to contact the door seal to the oven front
surface.
• Tighten two screws.
A
C
B
D
(2) To reduce gap located on part ‘B’
• Loosen two screws on the stopper hinge under, and
then push the door to contact the door seal to the oven
front surface.
• Tighten two screws.
(3) To reduce gap located on part ‘C’
• Loosen the screw on the interlock switch assembly
located the top of the oven body.
• Draw the interlock switch assembly inward as possible
to engage with the hook on the door bottom.
• Tighten a screw.
(4) To reduce gap located on part ‘D’
• Loosen the screw on the interlock switch assembly
located the bottom of the oven body.
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
12
5. To remove control panel parts.
B04
B03
B02
B01
B05
B06
B07
C/PANEL ASSEMBLY : PKCPSWZZ50
REF. NO
PART CODE
PART NAME
DESCRIPTION
Q'TY
B01
3518573450
SWITCH MEMBRANE
KQG-1N1A9A52
1
B02
3516737810
CONTROL-PANEL
KOR-1N1H SPRAY
1
B03
PKMPMSZZ40
PCB MAIN MANUAL AS
KQG-1N4A9A27
1
B04
7122401211
SCREW TAPPING
T2S TRS 4X12 MFZN
3
B05
3513702710
LEVER DOOR OPEN
PP
1
B06
441G430171
SPRING BUTTON
SWP DIA. 0.7
1
B07
3516915840
BUTTON DOOR OPEN
ABS SG-0760D, SG-175
1
REMARK
(1) Remove the screw which secure the CONTROL-PANEL, push up two snap fits and draw forward the control panel
assembly.
(2) Remove three screws which secure the PCB assembly to the CONTROL-PANEL.
(3) Disconnect membrane tail from the connector of the PCB assembly.
(4) Remove the PCB from the CONTROL-PANEL.
(5) Remove the membrane, holder LED, lever door open, spring button and button door open from the CONTROL-PANEL.
(6) Reverse the above steps for reassembly.
13
6. To remove high voltage capacitor.
1) Remove the screw which secure the grounding ring
terminal of the H.V. diode and the capacitor holder.
2) Remove the H.V. diode from the capacitor holder.
3) Reverse the above steps for reassembly.
◆ High voltage circuit wiring
7. To remove magnetron.
1) Remove the screw which secure the magnetron.
2) Remove the magnetron.
3) Reverse the above steps for reassembly.
NOTE : Never install the magnetron without the metallic gasket plate which is packed with each magnetron to
prevent microwave leakage. Whenever repair work is carried out on magnetron, check the microwave leakage. It
shall not exceed 4mW/cm2 for a fully assembled oven with door normally closed.
Metallic
gasket
plate
Cooling fin
Wave guide Magnetron antenna
Magnetron
antenna
Filament
terminal
Metallic gasket plate
<MAGNETRON>
14
8. To remove wind guide assembly.
1) Remove the screw which secure the wind guide assembly.
2) Draw forward the wind guide assembly.
3) Pull the fan from the motor shaft.
4) Remove two screws which secure the motor shaded pole.
5) Remove the motor shaded pole.
6) Reverse the above steps for reassembly.
9. To remove H.V.transformer.
1) Remove four screws holding the H.V.transformer.
2) Remove the H.V.transformer.
3) Reverse the above steps for reassembly.
15
10. To remove tray motor.
1) Remove the coupler in the cavity.
2) Turn the set upside down.
3) Cut the tray motor cover part from the base plate.
4) Remove the tray motor cover.
5) Remove a screw which secure the tray motor.
6) Remove the tray motor.
7) Reverse the above steps for reassembly except for
securing the tray motor cover with screw.
11. To remove heater assembly.
1) Remove one side of the heater harness.
2) Remove a screw which secure the cover insulator top.
3) Remove the cover insulator top.
4) Remove the heater top assembly.
5) Reverse the above steps for reassembly.
16
12. To remove heater parts
C01
C02
C03
C04
C05
HEATER TOP ASSEMBLY : 3512807640
REF. NO
PART CODE
PART NAME
DESCRIPTION
C01
3512765100
HARNESS HEATER
KOC-970T1S TEFLON
1
C02
7S312X40A1
SCREW TAPPING
T1 TRS 4X10 SE MFZN
2
C03
3510607800
BRACKET HEATER *T
SBHG T0.5
2
C04
3512808320
HEATER MIRACLON
60V AC, 500W, 240MM
2
C05
3511408100
COVER HEATER *T
STS430 T0.5
1
17
Q'TY
REMARK
INTERLOCK MECHANISM AND ADJUSTMENT
The door lock mechanism is a device which has been specially designed to completely eliminate microwave radiation when
the door is opened during operation, and thus to perfectly prevent the danger resulting from the leakage of microwave.
(1) Primary interlock switch
When the door is closed, the hook locks the oven door. If the door is not closed properly, the oven will not operate.
When the door is closed, the hook pushes the button of the microswitch. Then the button of the primary interlock switch
bring it under “ON” condition NO position (NO position).
(2) DOM switch and interlock monitor switch
When the door is closed, the hook pushes the lock lever downward. The hook presses the button of the interlock monitor
switch to bring it under “OFF” condition (NO position) and the lock lever presses the button of the DOM switch to bring it
under “ON” condition (NO position).
ADJUSTMENT :
Interlock monitor switch
When the door is closed, the interlock monitor switch should be opened (NO position) before other switches are closed.
When the door is opened, the interlock monitor switch should be closed (NC position) after other switches are opened.
(3) Adjustment steps
a) Loosen the mounting screw.
b) Adjust interlock switch assembly position.
Actuation distance of primary and secondary interlock switch shall be adjusted almost 0.7mm.
c) Make sure that lock lever moves smoothly after adjustment is completed.
d) Tighten completely a mounting screw.
NOTE :
Microwave emission test should be performed after adjusting interlock mechanism. If the microwave emission exceed
4mW/cm2, readjust interlock mechanism.
18
TROUBLESHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1. Check grounding before trouble checking.
2. Be careful of the high voltage circuit.
3. Discharge the high voltage capacitor.
4. When checking the continuity of the switches, fuse or high voltage transformer, disconnect one lead wire from these parts
and check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your meter.
NOTE : When electric parts are checked, be sure the power cord is not inserted the wall outlet.
Check wire harness, wiring and connected of the terminals and power cord before check the parts listed
below.
(TROUBLE 1) Oven does not operate at all ; any inputs can not be accepted.
CONDITION
CHECK
RESULT
Check continuity of interlock
monitor switch with door closed
Continuity
Fuse blows.
CAUSE
Malfunction of
interlock monitor switch
REMEDY
Replace
No Continuity
Check continuity of both primary
and secondary interlock switch
with door colosed
Check continuity of primary
inter-lock switch contact with
door partially open until
interlock mon-itor switch
contact close (COM ↔ NC)
No Continuity
Malfunction of
interlock switch
Replace
Continuity
Continuity
Shorted contacts of primary
interlock switch.
Replace
No Continuity
0Ωor infinite
Check continuity of primary
winding of low voltage
transformer
Approx.
220~320 Ω
(normal)
Normal
Disconnect one side of the lead
wire connected of from high
voltage transformer to the high
voltage capacitor and operate
the unit
Fuse again
blows
19
Defective low
voltage
transformer
Defective high
voltage capacitor
Defective high
voltage
transformer
Replace
Replace
Replace
CONDITION
CHECK
RESULT
CAUSE
REMEDY
Outlet has
proper
voltage Fuse
does not
blow.
Check continuity of
noise filter board
No
Continuity
Defective
magnetron
Replace
Check continuity of
power supply cord
No
Continuity
Open power
supply cord
Replace
Normal
Defective touch
control circuit
Replace
Malfunction of
D.O.M switch
Replace
Display do not shown
countdown
NOTE
All these switches must be replaced at the same time, please refer to “Interlock Mechanism And Adjustment”.
(TROUBLE 2) Display shows all figures selected, but oven does not start cooking, even though desired program and
time are set and START button is tapped.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
Turn table
motor and
oven lamp
do not turn
on
Check continuity of primary
interlock switch
No
Continuity
Malfunction of
primary interlock
switch
Adjust or
replace
Check continuity of secondary
interlock switch
No
Continuity
Check D.C. voltage being
supplied to RELAY (RY2) coil
0V
Defective touch
control circuit
Approx.
12 VDC
Faulty contacts of
RELAY (RY2) or
open relay coil
20
Malfunction of
secondary
interlock switch
Adjust or
replace
Replace
Replace
(TROUBLE 3)
No microwave oscillation even though fan motor rotates.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
No
microwave
oscillation
Check continuity of high
voltage capacitor terminals
with wires removed
Continuity
Defective high
voltage
transformer
Replace
Check continuity of high voltage
rectifier in forward and backward
direction with DC megger
Continuity in
backward
direction
Defective high
voltage rectifier
Replace
Connect megger leads to
magnetron terminal and
magnetron body
Continuity
Defective
magnetron
Replace
Check resistance of primary and
secondary coil of high voltage
transformer
0 Ωor ∞
Defective high
voltage
transformer
Replace
No
Continuity
Defective
magnetron
Replace
No
Continuity
Defective high
voltage
transformer
Replace
Check continuity of magnetron
with wires removed
Check continuity of filament
terminal of high voltage
transformer
0V
Check D.C. voltage being
supplied to RELAY (RY1) coil
Defective touch
control circuit
Approx
12 VDC
21
Faulty
contacts or
RELAY (RY1)
or open relay coil
Replace
Replace
(TROUBLE 4) The following visual conditions indicate a probable defective touch control circuit
1. Incomplete segments,
1) Segments missing.
2) Partical segments missing.
3) Digit flickering other than normal display slight flickering.
4) " :0" does not display when power is on.
2. A distinct change in the display are not on when they numbers is the
display.
M/W
Def.
Grill
Timer/ g
3. One or more digits in the display are not on when they should be.
4. Display indicates a number different from one touched.
5. Specific numbers (for example 2 or 3) will not display when the panel is touched.
6. Display does not count down or up with time cooking or clock operation.
7. Oven is programmable and cooks normally but no display shows.
8. Display obviously jumps in time while counting down.
9. Display counts down noticeably too fast while cooking.
10. Display does not show the time of day when the STOP/CLEAR button is pushed. (in case of setting the present time)
11. Oven lamp and turntable motor do not stop although cooking is finished. Check if the RELAY 2 contacts close.
If they close, replace P.C.B assembly.
CONDITION
CHECK
Display does
not show
programming
at all, even if
keyboard is
pressed
Check each pad for
continuity of the membrane
keyboard for the following
keyboard check procedure
RESULT
CAUSE
REMEDY
Normal
Malfunction
of the control
circuit board
Replace the
control circuit
board
Abnormal
Malfunction
of the membrane
keyboard
Replace the
membrane
keyboard
NOTE
Before following the particular steps listed above in the troubleshooting guide for the failure of membrane
keyboard, please check for the continuity of each wire-harness between the membrane keyboard and P.C.B.
assembly.
22
MEASUREMENT AND TEST
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
Microwave output power can be checked by indirectly measuring the temperature rise of a certain amount of water
exposed to the microwave as directed below.
PROCEDURE
1. A cylindrical container of borosilicate glass is used for the test. It has a maximum thickness of 3mm, an external
diameter of approximately 190mm and a height of approximately 90mm.
The mass of the container is determined.
2. At the start of the test, the oven and the empty container are at ambient temperature. Water having an initial
temperature of 10˚C ± 1˚C is used for the test. The water temperature is measured immediately before it is poured
into the container.
3. A quantity of 1000g ± 5g of water is added to the container and its actual mass obtained.
The container is then immediately placed in the centre of the oven shelf, which is in its lowest normal position.
The oven is operated and the time for the water
temperature to attain 20˚C ± 2˚C is measured. The oven
is then switched off and the final water temperature is
measured within 60s.
NOTE 1 - The water stirred is before its temperature is
measured.
NOTE 2 - Stirring and measuring devices are to have a
low heat capacity.
4. The microwave power output is calculated from the
formula
P = {4,187 • mw(T2-T1) + 0.55 • mc (T2-T0)}/t
where
P is the microwave power output, in watts ;
mw is the mass of the water, in grams ;
mc is the mass of the container, in grams ;
T0 is ambient temperature, in degrees Celsius ;
T1 is the initial temperature of the water, in degree Celsius ;
T2 is the final temperature of the water, in degrees Celsius ;
t
is the heating time, in seconds, excluding the magnetron filament heating-up time.
✻ The microwave power output is stated in watts, rounded off to the nearest 50W
CAUTION
1. Water load should be measured exactly to 1 liter.
2. Input power voltage should be exactly specified voltage (Refer to SPECIFICATIONS).
3. Ambient temperature should be 20 ± 2°C (68 ± 3.6°F)
✻ Heating time for power output: (T2 = T0)
A (second)
70
64
60
56
52
49
47
44
42
40
38
B (W)
600
650
700
750
800
850
900
950
1000
1050
1100
23
2. MICROWAVE RADIATION TEST
CAUTION
1. Make sure to check the microwave leakage before and after repair of adjustment.
2. Always start measuring of an unknown field to assure safety for operating personnel from microwave energy.
3. Do not place your hands into any suspected microwave radiation field unless the safe density level is known.
4. Care should be taken not to place the eyes in direct line with the source of microwave energy.
5. Slowly approach the unit under test until the radiometer reads an appreciable microwave leakage from the
unit under the test.
PROCEDURE
1. Prepare Microwave Energy Survey Meter, 600cc glass beaker, and glass thermometer 100°C (212°F).
2. Pour 275cc ± 15cc of tap water initially at 20 ± 5°C (68 ± 9°F) in
the 600 cc glass beaker with an inside diameter of approx. 95
mm(3.5 in.).
3. Place it at the center of the tray and set it in a cavity.
4. Close the door and operate the oven.
5. Measure the leakage by using Microwave Energy Survey Meter
with dual ranges, set to 2450MHz.
1) Measured radiation leakage must not exceed the value
prescribed below. Leakage for a fully assembled oven with door
normally closed must be less than 4mW/cm2.
2) When measuring the leakage, always use the 5 cm (2 in.)
space cone with probe. Hold the probe perpendicular to the
cabinet and door. Place the space cone of the probe on the
door, cabinet, door seem, door viewing screen, the exhaust air
vents and the suction air vents.
3) Measuring should be in a counter-clockwise direction at a rate
of 1 in./sec. If the leakage of the cabinet door seem is unknown,
move the probe more slowly.
4) When measuring near a corner of the door, keep the probe
perpendicular to the areas making sure the probe end at the base of the cone does not get closer than 2 in. from
any metal. If it does not, erroneous reading may result.
24
3. COMPONENT TEST PROCEDURE
• High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle.
• It is neither necessary nor advisable to attempt measurement of the high voltage.
• Before touching any oven components or wiring, always unplug the oven from its power source and discharge the
capacitor.
1. High voltage transformer
1) Remove connections from the transformer terminals and check continuity.
2) Normal readings should be as follows :
Secondary winding ... Approx. 110 Ω ±10%
Filament winding ... Approx. 0 Ω
Primary winding ... Approx. 1 Ω
2. High voltage capacitor
1) Check continuity of capacitor with meter on the highest OHM scale.
2) A normal capacitor will show continuity for a short time, and then indicate 10MΩonce the capacitor charged.
3) A shorted capacitor will show continuous continuity.
4) An open capacitor will show constant 10MΩ.
5) Resistance between each terminal and chassis should be infinite.
3. High voltage 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-back resistance of the diode,
otherwise an infinite resistance may be read A normal diode s resistance will be infinite in one direction and
several hundred KΩ. in the other direction.
4. Magnetron
For complete magnetron diagnosis, refer to "Measurement of the Microwave Power Output." Continuity checks can
only indicate and open filament or a shorted magnetron. To diagnose for an open filament or a shorted magnetron,
1) Isolate magnetron from the circuit by disconnecting the leads.
2) A continuity check across magnetron filament terminals should indicate 0.1 Ωor less.
3) A continuity check between each filament terminal and magnetron case should read open.
5. Fuse
If the fuse in the primary and monitor switch circuit is blown when the door is opened, check the primary and
monitor switch before replacing the blown fuse. In case the fuse is blown by an improper switch operation, replace
the defective switch and fuse at the same time. Replace just the fuse if the switches operate normally.
6. Interlock switches
1) You can test continuity of safety interlock and monitor switch by using ohmmeter.
2) The switch operation is checked by zero/unlimited.
The meter should indicate zero resistance.
3) The sequence of check is interlock monitor switch, primary and secondary interlock switches check.
25
WIRING DIAGRAM
26
PRINTED CIRCUIT BOARD
1. CIRCUIT CHECK PROCEDURE
1. Low voltage transformer check
The low voltage transformer is located on the P.C.B.
Measuring condition: Input voltage: 120V / Frequency: 60Hz
Terminal Voltage
LOAD
NO LOAD
4-7
AC 12.6 V
AC 14.7 V
NOTE
1. Refer to Ciruit Diagram (point 4).
2. Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source
voltage.
3. The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
2. Voltage Check
- Key check point
NO
CHECK POINT
1
IC1 PIN 5
2
IC1 PIN 8
REMARK
5VDC
5V
0V
3
T
T:20ms(50Hz)
T
T:250ns(4MHz)
IC1 PIN 35 OR 36
5V
0V
- Check method
NO
MEASURE POINT
WAVE FORM
REMEDY
REMARK
1
MP1
DC 5V±0.25V
Replace VL1, EC1
NO LOAD
2
MP2
DC 12V±2.0V
Replace EC2, D11,13,14
NO LOAD
NOTE
Each measure point must be measured with GND points.
27
MP1
GND
MP2
Measure Point
28
3. When there is no microwave oscillation
1) When touching START pad, oven lamp does not turn on.
Fan motor does not rotate, but cook indicator in display comes on.
✻ Cause : RELAY 2 does not operate. → refer to Circuit Diagram (point 3)
- Check method
POINT
A
B
RELAY 2 ON
5VDC
GND
RELAY 2 OFF
GND
12VDC
STATE
2) When touching START pad, oven lamp turns on.
Fan motor and turntable rotate and cook indicator in display comes on.
✻ Cause : RELAY 1 does not operate. → refer to Circuit Diagram (point 2)
- Check method
POINT
A
B
RELAY 1 ON
5VDC
GND
RELAY 1 OFF
GND
12VDC
STATE
4. When there is no grill oscillation.
✻ Cause : RELAY 3 does not operate. → refer to Circuit Diagram (point 6)
- Check method
POINT
A
B
RELAY 3 ON
5VDC
GND
RELAY 3 OFF
GND
12VDC
STATE
5. When the door is opened during operation, the count down timer does not stop.
→ refer to Circuit Diagram (point 1)
- Check method
POINT
A
B
1) DOOR OPEN
OPEN
5VDC
2) DOOR CLOSED
CLOSE
GND
STATE
CHECK NO
1
METHOD
REMEDY
Check the stage(ON, OFF) of the door open monitor
switch by resistance measurement.
Replace door open monitor switch.
6. When the digital clock does not operate properly.
→ refer to Circuit Diagram (point 5)
POINT
A
WAVE FORM
5V
0V
T
T: 16.67 ms(60Hz)
❈ If clock does not keep exact time, you must check resistor R20 zener diode ZD2.
29
2. PCB CIRCUIT DIAGRAM
30
3. PCB LOCATION NO.
NO
NAME
SYMBOL
SPECIFICATION
PART CODE
Q’TY
1
BUZZER
BZ1
BM-20K
3515600100
1
2
C ARRAY
CA1
7P(6) 1000PF M 50V
CN6XB-102M
1
3
CAPACITOR ELEC
EC1
50V RS 10uF
CEXE1H100A
1
4
CAPACITOR ELEC
EC2
25V RSS 1000MF
CEXF1E102V
1
5
CONNECTOR WAFER
CN1
YW396-02V
3519150520
1
6
CONNECTOR WAFER
CN2
FCZ 254-11
441M367160
1
7
CONNECTOR WAFER
CN3
YW396-05AV
3519150510
1
8
DIODE SWITCHING
D1~5,D7~D12
1N4148
DZN4148---
11
9
DIODE RECTIFIER
D13,14
KN4004A
DZN4004A--
2
10
DIODE ZENER
ZD2
UZ- 5.1BSB 1/2W
DZUZ5R1BSB
1
11
LED DISPLAY
DP1
TOF-4461BG-B10
DT0F4461BG
1
12
PCB MAIN
M345
81.5X139.9
3514332110
1
13
R ARRAY
RA1
8P(7) 1/8 100K OHM J
RA-88X104J
1
14
R ARRAY
RA2
7P(6) 1/8 100K OHM J
RA-87X104J
1
15
RESISTOR
R2~8
1/6W 330 5%
RD-AZ331J-
7
16
RESISTOR
R1,10,13,17,22
1/6W 1K 5%
RD-AZ102J-
5
17
RESISTOR
R15,R23
1/6W 4.7K 5%
RD-AZ472J-
2
18
RESISTOR
R9
1/6W 100K 5%
RD-AZ104J-
1
19
RESISTOR
R19,20
1/6W 10K 5%
RD-AZ103J-
2
20
RESISTOR
R18
1/6W 20K 5%
RD-AZ203J-
1
21
RESISTOR
R14
1/6W 1M 5%
RD-AZ105J-
1
22
RESISTOR
R21
1/4W 51 5%
RD-4Z510J-
1
23
RESONATOR CERA
CR1
CRT 4.00MS
5P4R00MTS-
1
24
IC REGULATOR
VL1
MC7805C
1CPMC7805C
1
25
TRANSISTOR
Q1~5
KRA106M
TZRA106M--
5
26
TRANSISTOR
Q8~11
KRC106M
TZRC106M--
4
27
TRANSISTOR
Q12
KTC3198GR
TZTC3198GR
1
28
IC RESET
IC2
KIA7033AP
1K1A7033AP
1
29
CAPACITOR CERA
C3,C5
102 50V Z AXIAL
CCZB1H102K
2
30
CAPACITOR CERA
C1,2,4,6,7
104 50V Z AXIAL
CCZF1H104Z
5
31
TRANS POWER
LVT1
DMR-631P
5EPU035302
1
32
WIRE COPPER
J1~J6
1/0.52 TIN COATING
85801052GY
6
33
WIRE COPPER
SJ2,SJ4
1/0.52 TIN COATING
85801052GY
2
34
WIRE COPPER
J7
1/0.52 TIN COATING
85801053GY
1
35
SW RELAY
RY1, RY4
G5G-1A DC12V
5SC0101121
2
36
SW RELAY
RY2
OJ-SS-112LM 1C 1P
5SC0101404
1
37
IC MICOM
IC1
HMS81C1716B-HN072
150SG1N4A-
1
31
EXPLODED VIEW AND PARTS LIST
1. DOOR ASSEMBLY
Refer to Disassembly and assembly.
2. CONTROL PANEL ASSEMBLY
Refer to Disassembly and assembly.
3. TOTAL ASSEMBLY
32
REF.NO
PART CODE
A00
B00
F01
F02
F03
F04
F05
F06
F07
3511727430
PKCPSWZZ50
3510810520
3516004100
3516120300
3511408220
3518905900
3512807640
7122401211
F08
F09
F10
F11
F12
F13
F14
F15
F16
F17
F18
F19
F20
F21
F22
F23
F24
F25
F26
F27
F28
F29
F30
F31
F32
F33
F34
F35
F36
F37
F38
F39
F40
F41
F42
F43
F44
F45
F46
7122401211
7S312X40A1
35113TCN35
7S312X40A1
7121402511
3963821610
3512517430
3512517000
3518003420
3516004000
7S432X4081
3513003200
3518302201
3518400400
3518124300
3516003700
3510317510
7S312X40A1
3512101400
7272400811
3515201101
3512783450
4415A17352
4415A17352
4415A66600
3513702600
3513811700
3513601500
7121400611
3966820200
3518906400
3513003410
7272400811
3511405100
3517400600
3512517300
3514700710
3517203500
3517207000
PART NAME
DESCRIPTION
Q'TY
DOOR AS
CONTROL-PANEL AS
CABINET AS
SPECIAL SCREW
CAVITY AS
COVER INSULATOR *T
THERMOSTAT
HEATER *T AS
SCREW TAPPING
KOR-1N1A9S51 SPRAY
KQG-1N1A9A52
PCM 0.5T SV1401C
T1 TRS LR4 POLE 4X10 MFZN
KQG-1N1A9A52
SBHG T0.5
OFF:75 ON:65 V #187
KQG-1N1A9A52
T2S TRS 4X12 MFZN
1
1
1
3
1
1
1
1
1
SCREW TAPPING
SCREW SPECIAL
CORD POWER AS
SCREW SPECIAL
SCREW TAPPING
MOTOR SHADED POLE
GUIDE WIND AS
FAN
MAGNETRON
SPECIAL SCREW
SPECIAL SCREW
HOLDER HV CAPACITOR
CAPACITOR HV
DIODE HV
TRANS HV
SPECIAL SCREW
BASE
SCREW SPECIAL
FOOT
SCREW TAPTITE
STOPPER HINGE *U
HARNESS MAIN
SW MICRO
SW MICRO
SW MICRO
LEVER LOCK
LOCK
LAMP
SCREW TAPPING
MOTOR SYNCRO
THERMOSTAT
HOLDER THERMOSTAT
SCREW TAPTITE
COVER WAVE GUIDE
COUPLER
GUIDE ROLLER
ROLLER
TRAY
TRAY RACK
T2S TRS 4X12 MFZN
T1 TRS 4X10 SE MFZN
3X16AWG 40X40 120-RTML
T1 TRS 4X10 SE MFZN
T2S PAN 4X25 MFZN
120V 60HZ MW10XA-M01
KOR-63150A
PP
RM228JFP 6CF
T2 BOLT FLANGE 5X12 DACRO
TT3 TRS 4X8 SE MFZN
SECC T0.5
2100VAC 0.98UF #187 75MM
HVR-1X-3AB 12KV #187
DYAS10A0-1NA A
TT3 HEX 4X8 FLG MFZN
SBHG T0.5
T1 TRS 4X10 SE MFZN
DASF-310
TT3 TRS 4X8 MFZN
SCP-1 T2.5
KQG-1N1A9A52
VP-533A-OF SPNO #187 200G
VP-533A-OF SPNO #187 200G
VP-532A-OF SPNC #187 200G
POM
POM BLACK
BL 125V 25W T25 C5A H187
T2S PAN 4X6 MFZN
120V 2W GM-16-12F17
OFF:85 ON:75 H #187 NB
PP(BK)
TT3 TRS 4X8 MFZN
MICA T0.35
XAREC
PP 5113MF6 A353B
TEFLON D:14.5
GLASS
MSWR3 107MM DIA:3
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
4
1
6
2
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
33
DAEWOO ELECTRONICS CORP.
1-2, Jeo-dong 1(il)-ga, Jung-gu, Seoul, Korea
C.P.O. BOX 8003 SEOUL, KOREA
TELEX: DWELEC K28177-8
CABLE: “DAEWOOELEC”
S/M NO. :
PRINTED DATE: Oct. 2009
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