Daewoo KOR-6L35 User manual

Service Manual
Microwave Oven
Model: KOR-6L35
S/M No. : OR6L353S001
May. 2010
✔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).

3
SPECIFICATIONS
POWER SUPPLY 230V AC, 50Hz SINGLE PHASE WITH GROUNDING
INPUT POWER 1000 W
MICROWAVE ENERGY OUTPUT 700 W
FREQUENCY 2,450MHz
OUTSIDE DIMENSIONS (W H D) 446 x 270 x 319 mm
CAVITY DIMENSIONS (W H D) 295 x 219 x 303 mm
CAVITY VOLUME 20 L
NET WEIGHT APPROX. 10.6 Kg
TIMER 35min. DUAL SPEED
POWER SELECTIONS 5 Levels
* Specifications are subject to change without notice.

4
1. OUTER DIMENSION
446 319
270
EXTERNAL VIEW

17
(TROUBLE 1) Oven does not operate at all ; any inputs can not be accepted.
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.
Does the
fuse blow?
NO
NONO
Does the fan motor work when you
shut the door and turn the timer?
YES
If outlet has proper voltage, check
continuity of power supply cord. Replace power supply cord.
NO Continuity
Check continuity of interlock
monitor switch with door shut. Replace primary, secondary interlock switch and interlock monitor switch.
Continuity
Both continuity
Replace fuse and check
continuity of both interlock
switch's contact and monitor
switch's contact with door
partially open until monitor
switch contact.
Replace primary, secondary interlock
switch and interlock monitor switch.
NO
Fuse again
Disconnect one side of the
lead wire connected from
transformer to the high
voltage capacitor, and operate
oven.
Replace high voltage capacitor.
Replace high voltage transformer
Normal
(NOTE1)
(NOTE1)
NOTE1 : All these switches must be replaced at the same time, please refer to “Interlock Mechanism And
Adjustment”

18
Does the oven lamp light?
Does the turntable turn?
YES
YES
Continuity
Does the fan motor work when you
shut the door and turn the timer?
Check the isolation of filament
winding of high voltage
transformer.
Replace high voltage
transformer.
NO Continuity
Replace magnetron
Good
Replace or repair oven lamp,
turntable motor.
NO
If microwave do not
oscillate, check continuity
of filament of magnetron.
Poor continuity
NO
Continuity Check continuity
filament tap (3.3V)
of high voltage.
Replace high
Voltage transformer
No Continuity
Continuity
Check continuity
filament tap (3.3V)
of high voltage.
Replace high
Voltage transformer
Continuity in
the reverse
direction.
Replace magnetron
Normal reading
should be
approx. 0
Meter with 6V or higher
voltage batteries should
be used to check the normal
direction resistance of
the diode

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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
where
Pis the microwave power output, in watts ;
mwis the mass of the water, in grams ;
mcis the mass of the container, in grams ;
T0is ambient temperature, in degrees Celsius ;
T1is the initial temperature of the water, in degree Celsius ;
T2is the final temperature of the water, in degrees Celsius ;
tis 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
✻ Heating time for power output: (T
2
= T
0
)
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)
P = {4,187 • mw(T2-T1) + 0.55 • mc (T2-T0)}/t
70
600
64
650
60
700
56
750
52
800
49
850
47
900
44
950
42
1000
40
1050
38
1100
A (second)
B (W)

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2. MICROWAVE RADIATION 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(3.7 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/cm
2
.
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.
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.

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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. 214.1 Ω±10%
Filament winding ... Approx. 0 Ω
Primary winding ... Approx. 2.4125 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 in both directions. A normal diode's resistance will be infinite in one direction and several hundred k Ωin 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.

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WIRING DIAGRAM

23
1. DOOR ASSEMBLY
Refer to Disassembly and assembly.
2. CONTROL PANEL ASSEMBLY
Refer to Disassembly and assembly.
3. GUIDE WIND ASSEMBLY
Refer to Disassembly and assembly.
4. TOTAL ASSEMBLY
EXPLODED VIEW AND PARTS LIST