Daewoo KOR-1A4H0P User manual

Service Manual
Microwave Oven
Model : KOR-1A4H0P
DAEWOO ELECTRONICS CO., LTD.
http://svc.dwe.co.kr
S/M No.:

1
TABLE OF CONTENTS
SAFETY AND PRECAUTIONS ........................................................................................................ 2
1. FOR SAFE OPERATION ............................................................................................................. 2
2. FOR SAFE SERVICE PROCEDURES ........................................................................................ 2
SPECIFICATIONS ............................................................................................................................ 3
EXTERNAL VIEW ............................................................................................................................ 4
1. OUTER DIMENSION .................................................................................................................... 4
2. FEATURE DIAGRAM ................................................................................................................... 5
3. CONTROL PANEL ....................................................................................................................... 6
INSTALLATION ................................................................................................................................ 7
OPERATIONS AND FUNCTIONS ................................................................................................... 8
DISASSEMBLY AND ASSEMBLY .................................................................................................. 9
INTERLOCK MECHANISM AND ADJUSTMENT ........................................................................... 16
TROUBLE SHOOTING GUIDE ........................................................................................................ 17
MEASUREMENT AND TEST ........................................................................................................... 21
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT ..................................................... 21
2. MICROWAVE RADIATION TEST ................................................................................................ 22
3. COMPONENT TEST PROCEDURE ............................................................................................ 23
WIRING DIAGRAM .......................................................................................................................... 24
PRINTED CIRCUIT BOARD ............................................................................................................ 25
1. CIRCUIT CHECK PROCEDURE ................................................................................................. 25
2. P.C.B CIRCUIT DIAGRAM ........................................................................................................... 28
3. P.C.B LOCATION NO .................................................................................................................. 29
EXPLODED VIEW AND PARTS LIST ............................................................................................. 30
1. DOOR ASSEMBLY ...................................................................................................................... 30
2. CONTROL PANEL ASSEMBLY ................................................................................................... 30
3. TOTAL ASSEMBLY ...................................................................................................................... 30
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) 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.

2
SAFETY AND PRECAUTIONS
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 immediately.
IMPORTANT
The wire in this mains lead coloured in accordance with the following code.
Green-and-yellow : Earth
Blue : Neutral
Brown : Live
As the colours of the wires in the manins lead of this appliance may not correspond with the coloured markings
identifying the terminals in your plug, proceed as follows.
The wire which is coloured green-and-yellow must be connected to the termianl in the plug which is marked with the
letter 'E', earth symbol or coloured green-and-yellow.
The wire which is coloured blue must be connected to the terminal which is marked with the letter 'N' or
coloured black.
The wire which is coloured brown must be connected to the terminal which is marked with the letter 'L' or
coloured red.
This oven is designed for counter-top use only.
NOTE

3
SPECIFICATIONS
SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
1) KOR-1A4H
MODEL KOR-1A4H0P
POWER SUPPLY
220V~60Hz, SINGLE PHASE WITH EARTHING
POWER
CONSUMPTION
MICROWAVE 1400W
GRILL
COMBINATION
MICROWAVE ENERGY OUTPUT
1000W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 539 x 300 x 435 mm (21.2 x 11.8 x 17.1 in.)
CAVITY DIMENSIONS (W X H X D) 354 x 228 x 370 mm (13.9 x 9.0 x 14.6 in.)
NET WEIGHT APPROX. 16.5 Kg ( 35.4 lbs.)
TIMER 99 min. 90 sec.
FUNCTION SELECTIONS MICROWAVE
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.1 Cu.Ft.

4
EXTERNAL VIEW
1. OUTER DIMENSION
1) KOR-1A4H
435539
300
MICROWAVEOVEN
M/W
Dish
Warmer
Fresh
Vegetable
Frozen
Vegetable
Auto Defrost
Fish Poultry Meat
1hour
Power
Kitchen
Timer
STOP/
CLEAR
START/
SPEEDY COOK
Defrost
Clock
10 m. 1 m. 10 s.
10min. 1min.
Frozen
Pizza
Pasta
Beverage
Def. Timer Lock g
KOR- 1A4H

5
1) KOR-1A4H
1. DOOR SEAL
Door seal maintains the microwave within the oven cavity and prevents microwave leakae.
2. DOOR HOOK
When the door is closed, it will automatically lock shut. If the door is opened while oven operating, magnetron tube will
immediately stop operating.
3. DOOR SCREEN
Allows viewing of food. Microwave cannot pass through perforations in screen.
4. SPATTER SHIELD
Protects the microwave outlet from splashes of cooking foods.
5. OVEN LAMP
Automatically turns on during oven operating.
6. SAFETY INTERLOCK SYSTEM
7. CONTROL PANEL
8. 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.
9. OVEN FRONT PLATE
10. ROLLER GUIDE
Supports the glass cooking tray.
EXTERNAL VIEW
①
③⑨ ④
⑥
⑩
⑧
②⑤
2. FEATURE DIAGRAM
MICROWAVEOVEN
M/W
Dish
Warmer
Fresh
Vegetable
Frozen
Vegetable
Auto Defrost
Fish Poultry Meat
1hour
Power
Kitchen
Timer
STOP/
CLEAR
START/
SPEEDY COOK
Defrost
Clock
10 m. 1 m. 10 s.
10min. 1min.
Frozen
Pizza
Pasta
Beverage
Def. Timer Lock g
KOR- 1A4H
⑦

6
1) KOR-1A4H
1. Time set pad - Used to set the cooking time and the present time.
2. Display - Cooking time, power level, indicators and present time are displayed.
3. One touch - Used to cook or reheat specific quantities of food.
4. More - Used to add time to cooking.
5. Less - Used to remove time from cooking.
6. Auto Defrost - Used to defrost foods(for weight)
7. Power - Used to set power level.
8. Defrost - Used to defrost foods.(for time)
9. Kitchen Timer - Used as a minute timer, delay cooking, hold setting after cooking.
10. Clock - Used to set clock.
11. Stop/Clear - Used to stop the oven operation or to delete the cooking data.
12. Strat/Easy cook - Used to start the oven and also used to set a reheat time.
EXTERNAL VIEW
3. CONTROL PANEL
⑥
⑤
④
③
②
⑦
⑨
⑪
⑩
⑧
⑫
①
MICROWAVE OVEN
M/W
Dish
Warmer
Fresh
Vegetable
Frozen
Vegetable
Auto Defrost
Fish Poultry Meat
1hour
Power
Kitchen
Timer
STOP/
CLEAR
START/
SPEEDY COOK
Defrost
Clock
10 m. 1m. 10 s.
10min. 1min.
Frozen
Pizza
Pasta
Beverage
Def. Timer Lock g
KOR - 1A4H

7
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 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.
Position the oven as far from them as possible.
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 6 amperes, 220 Volts, 60 Hz.
Power supply cord is about 0.8 meters long.
The voltage used must be the same as specified on this oven. Using a higher voltage may result in a fire or other accident
causing oven damage. Using low voltage will cause slow cooking. W e are not responsible for damage resulting from use
of this oven with a voltage of ampere fuse other than those specified.
This appliance is supplied with cable of special type, which, if damaged, must be repaired with cable of same type.
Such a cable can be purchased from DAEWOO and must be installed by a Qualified Person.
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. Do not operate the oven if it is colder than room temperature
(This may occur during delivery in cold weather.) Allow the oven to become room temperature before operating.
This appliance must be earthed. In the event of an electrical short circuit, earthing reduces the risk of the electric shock by
providing an escape wire for the electric current. This appliance is equipped with a cord having a earthing wire with a earthing
plug. The plug must be plugged into an outlet that is properly installed and earthed.
WARNING
Improper use of the earthing plug can result in a risk of electric shock. Consult a qualified electrician or serviceman if
the earthing instructions are not completely understood, or if doubt exists as to whether the appliance is properly
earthed, and either : If it is necessary to use an extension cord, use only a 3-wire extension cord that has a 3-blade
earthing plug, and a 3-slot receptacle that will accept the plug on the appliance. The marked rating of the extension
cord should be equal to or greater than the electrical rating of the appliance, or Do not use an extension cord.
EARTHING INSTRUCTIONS

8
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 off.
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 the 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.
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 tim es P-00 0 %
OPERATIONS AND FUNCTIONS
Make sure the oven is properly installed and plugged into the electrical outlet.

9
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 safety 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 scredriver and ware rubber gloves when servicing the high voltage side.
3. Discahrge the high voltage capacitor before touching any oven components or wiring.
(1) Check the earthed.
Do not operate on a two-wire extension cord.
The microwave oven is designed to be used with earthed.
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 stopped and 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 12A fuse is blown out 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.
Service personnel should remove their watches whenever working close to or replacing the magnetron.
When servicing th 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.
CAUTION
WARNING

10
DISASSEMBLY AND ASSEMBLY
1. To remove cabinet
1) Remove three screws on cabinet back.
2) Push the cabinet backward.
2. To remove door assembly
1) Remove screws which secure the stopper hinge top.
2) Remove the door assembly from top plate of cavity.
3) Reverse the above for reassembly.
After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.
NOTE

11
1) KOR-1A4H
(1) Remove the gasket door from door plate.
(2) Remove the barrier screen inner from door plate.
(3) Remove the door frame from door plate.
(4) Remove the stopper hinge top from door plate.
(5) Remove the spring and the hook.
(6) Remove the barrier screen outer from door frame.
(7) Remove two screws holding the handle.
(8) Remove the handle from door frame.
(9) Reverse the above steps for reassembly.
REF NO. PART CODE PART NAME DESCRIPTION QíTY REMARK
A01 3511711300 DOOR PAINTING AS KOR-1A1G0A 1
A02
3513100730 HOOK POM BLACK 1
A03
3515101300 SPRING HOOK PW1 1
A04
3517005910 BARRIER-SCREEN * O GLASS T3.2 1
A05
3512204320 FRAME DOOR ABS XR-401 SG-175 1
A06
3511604700 DECORATOR DOOR * T STS304 T0.6 1
A07
3511604710 DECORATOR DOOR * U STS304 T0.6 1
A08
3515202900 STOPPER HINGE * T AS KOR-121M0A 1
A09
3512603400 HANDLE DOOR * T STS304 T0.6 HAIR LINE 1
A10
3512603300 HANDLE DOOR * U ABS XR-401 H-2938 1
A11
7122401211 SCREW TAPPING T2S TRS 4*12 MFZN 2
A12
3517005800 BARRIER-SCREEN * I PETP T0.1 1
A13
3512301900 GASKET DOOR PP 1
DISASSEMBLY AND ASSEMBLY
3. To remove door parts

12
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 stopper hinge top, and then
push the door to contact the door seal to oven front surface.
Tighten two screws.
2) To reduce gap located on part 'B '
Loosen two screws on stopper hinge under, and then
push the door to contact the door seal to oven front surface.
Tighten two screws.
3) To reduce gap located on part 'C'
Loosen a screw on interlock switch assembly located top of oven body.
Draw the interlock switch assembly inward as possible to engage with hook on the door bottom.
Tighten a screw.
4) To reduce gap located on part 'D'
Loosen a screw on interlock switch asembly located bottom of oven body.
and (4) are same as step (3).
DISASSEMBLY AND ASSEMBLY
A small gap may be acceptable if the microwave leakage does not exceed 4mW/
NOTE
cm 2
MICROWAVEOVEN
M/W
Dish
Warmer
Fresh
Vegetable
Frozen
Vegetable
AutoDefrost
Fish Poultry Meat
1hour
Power
Kitchen
Timer
STOP/
CLEAR
START/
SPEEDYCOOK
Defrost
Clock
10 m. 1 m. 10 s.
10min. 1min.
Frozen
Pizza
Pasta
Beverage
Def. Timer Lock g
KOR- 1A4H
AC
BD

1) KOR-1A4H
1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly.
2) Remove four screws which secure the PCB assembly to control panel.
3) Disconnect membrane tail from the connector of the PCB assembly.
4) Detach membrane from the control panel.
5) Reverse the above steps for reassembly.
REF NO. PART CODE PART NAME DESCRIPTION Q'TY REMARK
B01 3511604800 DECORATOR C-PANEL STS304 T0.6 1
B02 3518522140 SWITCH MEMBRANE KOR-1A4H0P 1
B03 3516722320 CONTROL-PANEL ABS SG-175 SG-0760D 1
B04
PKMPMSXT00 PCB AS KOR-1A4H0P 1
B05 7122401211 SCREW TAPPING T2S TRS 4* 12 MFZN 3
DISASSEMBLY AND ASSEMBLY
5. To remove control panel parts.
13

DISASSEMBLY AND ASSEMBLY
6. To remove high voltage capacitor.
1) Remove a 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 a 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/cm
2
for a fully assembled oven with door normally closed.
14

DISASSEMBLY AND ASSEMBLY
8. To remove wind guide assembly.
1) Remove a 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

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.
(2) Secondary interlock switch and interlock monitor switch
When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the interlock
monitor switch to bring it under NO condition and presses the button of the secondary interlock switch to bring it under
ON condition.
(3) Adjustment steps
a) Loosen the one mounting screw.
b) Adjust interlock switch assembly position.
c) Make sure that lock lever moves smoothly after adjustment is completed.
d) Tighten completely one mounting screw.
ADJUSTMENT
Interlock monitor switch
When the door is closed, the interlock monitor switch should be changed(NO condition) before other switches are closed.
When the door is opened, the interlock monitor switch should be changed(NC condition) after other switches are opened.
NOTE
Microwave emission test should be performed after adjusting interlock mechanism.
If the microwave emission exceed 4mW/cm
2
, readjust interlock mechanism.
16

TROUBLE SHOOTING 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.
(TROUBLE 1) Oven does not operate at all : any inputs can not be accepted.
Continuity
No Continuity
Continuity
0 infiniteor
Approx.
150~310
(normal)
Replace
NOTE 1
Replace
NOTE 1
Replace
Replace
Check continuity o f
primary winding of low
voltage transformer
Malfunction
of interlock
monitor
switch
Defective low
voltage
transformer
Check continuity of
interlock monitor switch
with door closed
Replace fuse
Check continuity of primary
interlock switch contact
with door partially open
until interlock monitor switch
contact close
Shorted contacts
of primary
interlock switch.
Fuse again
blows
Disconnect one side of the
lead wire connected form
high voltage transformer
to the high voltage capacitor
and operate the unit
Norma l Defective high
voltage capacitor
Defective high
voltage transformer
Replace
CHECK RESULT CAUSE REMEDYCONDITION
Fuse blows
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.
NOTE
17

TROUBLE SHOOTING GUIDE
CONDITION CHECK RESULT CAUSE REMEDY
Outlet has
proper voltage
Fuse does not
blow.
Check continuity of
magnetron
No
Continuity
Defective
magnetron
Replace
Display do not
shown countdown
No
Continuity
Normal Defective touch
control circuit
Open power
supply cord
Malfunction of
secondary
interlock switch
Replace
Check continuity of
power supply cord
Replace
Replace
All these switches must be replaced at the same time, please refer to ìInterlock Mechanism And Adjustmentî.
NOTE
CONDITIONCHECK RESULT CAUSE REMEDY
Turn table
motor, and
oven lamp do
not turn on
No
Continuity
Check continuity of
primary interlock switch
Check continuity of
secondary interlock switch
Check D.C. voltage
being supplied to
RELAY (RY2) coil
Malfunction
of primary
interlock switch
Malfunction
of secondar
interlock switch
Defective
touch control
circuit
Fault
contacts of
RELAY
(RY2) or open
relay coil
Adjust or
Replace
Adjust or
Replace
Replace
Replace
No
Continuity
0 V
Approx
15 VDC
(TROUBLE 2) Display shows all figures selected, but oven does not start cooking, even thouh desired program and time are
set and start pad is tapped.
18

(TROUBLE 3) No microwave oscillation even though fan motor rotates.
TROUBLE SHOOTING GUIDE
CONDITIONCHECK RESULT
Continuity
Continuity in
backward
direction
0 ΩOr infnity
No
Continuity
No
Continuity
0 V
Appro x
15 VDC
CAUSE
Defective
high voltag
transformer
Defective
high voltag
rectifier
Defective
magnetron
Defectiv e
magnetro n
Defective
high voltag
transformer
Defective
high voltage
transformer
Defective
touch control
circuit
Faulty
contacts of
RELAY
(RY1) or open
relay coil
REMEDY
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
No microwave
oscillation
Check continuity of high
voltage rectifier in
forward and backward
direction with DC
megger
Check continuity of high
voltage capacitor
terminals with wires
removed
Connect megger leads to
magnetron terminal and
magnetron body
Check resistance of
primary and secondary
coil of high voltage
transformer
Check continuity of
magnetron with wires
removed
Check continuity of
filament terminal of high
voltage transformer
Check D.C. voltage
being supplied to
RELAY (RY1) coil
Continuity
19