Whirlpool AVM542 User manual

WHIRLPOOL ELECTRICAL APPLIANCES CO. LTD. SERVICE MANUAL
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WHIRLPOOL ELECTRICAL APPLIANCES
COMPANY LIMITED
SERVICE INFO MANUAL
MODEL: AVM542
SKU No.: 853854258291
DATE: October 7, 2005
REVISION: b

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CONTENTS
1. SPECIFICATIONS
2. SAFETY PRECAUTIONS
3. INSTALLATION REQUIREMENTS
3.1 GENERAL
3.2 GROUNDING INSTRUCTIONS
4. SCHEMATIC DIAGRAM
5. MICROWAVE AND MICROWAVE LEAKAGE TEST
5.1 MICROWAVE TEST
5.2 MICROWAVE LEAKAGE TEST
6. TROUBLE SHOOTING GUIDE
6.1 CAUTION AND IMPORTANCE
6.2 MICROWAVE LEAKAGE
6.3 QUICK REFERENCE
7. MAJOR COMPONENT TESTS
7.1 HV TRANSFORMER
7.2 HV CAPACITOR
7.3 HV DIODE
7.4 MAGNETRON
7.5 INTERLOCK SWITCH SYSTEM
8. PART LIST & EXPLODED DIAGRAM

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1. SPECIFICATION
Model
AVM542
Outer dimension(H x W x D)
285x456x392mm
Volume of cavity
17.8Liter
Basic function
Microwave only cooking
Control
Electronic touch foil control
99-minute cook time
10-level microwave power level
Programmable
Power supply
220V, 60 Hz, single phase
Output power
Microwave: 800W
Power consumption
Max 1250W
Current consumption
8 A
Microwave frequency
2450 MHz

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2. SAFETY PRECAUTIONS
This manual is intended for use by personnel with adequate background in
electrical, electronic and mechanical engineering. Any improper attempt to repair
this oven may result in personal injury and property damage. The manufacturer or
seller cannot be hold responsible for the interpretation of this manual nor can they
assume any liability in connection with its use.
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 when the door is opened.
b. Make the following safety checks on all ovens to be serviced before
activating the magnetron or other microwave sources, and make repairs
when 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 the 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 connection.
d. Any defective or misadjusted components in the interlock, monitor, door
seal, and microwave generation and transmission system 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.
TO PREVENT ELECTRICAL SHOCK, PAY EXTREME CAUTION
WHEN DIAGNOSING OVEN WITH OUTER CASE REMOVED AND
POWER TURNED “ON”. THE HIGH VOLTAGE SECTION OF THE
POWER SUPPLY, INCLUDING FILAMENT LEADS, ARE AT A HIGH
TENSION OF -4000 VOLTS. ALSO, ENSURE THAT THE HIGH
VOLTAGE CAPACITOR IS DISCHARGED.

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3. INSTALLATION REQUIREMENTS
3.1 GENERAL
1. The oven should be placed on a flat and stable surface
2. Place the oven away from high temperature and steam sources.
3. Clearance of at least 5cm (2”) on each side must be provided to allow
adequate ventilation.
4. The microwave oven must be plugged directly to a 3-prong wall receptacle
which is properly grounded.
5. The power source must be 230V 50Hz 8A single phase.
3.2 GROUNDING INSTRUCTIONS
IMPORTANCE:
DISCONNECT POWER BEFORE SERVICING, RECONNECT ALL
GROUNDING DEVICES.
All mechanical parts of this appliance capable of conducting electricity are
grounded. In the event of an electrical short circuit, grounding reduces the risk of
electric shock. This appliance is equipped with a cord having a grounding wire
with a ground plug. The plug must be plugged into an outlet that is properly
installed and grounded.
WARNING:
IMPROPER USE OF THE GROUNDING PLUG MAY RESULT IN
ELECTRICAL SHOCK.
If grounding wires, screws, straps, clips, nuts or washers used to complete a path
to ground are removed for service, they must be returned to their original
positions and properly fastened.
GROUNDING SPECIFICATION:
Leakage current: 0.75mA max.
Ground path resistance: 0.1ohm max.

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4. SCHEMATIC DIAGRAM

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5. MICROWAVE AND MICROWAVE LEAKAGE TESTS
5.1 MICROWAVE TEST
The following is a simple test to check if the appliance is generating microwave
energy. This test is not intended to be an accurate test. An accurate measurement
of output power must be performed under strict control following the IEC
standard. In field service, accurate measurement of output power is usually not
required.
1. Prepare a beaker of water of quantity about 1000cc.
2. Measure the temperature of the water before putting into the oven.
3. Heat the water in the oven with full power (microwave only) for 60 seconds.
4. Again measure the temperature of the water.
5. If the temperature rise by about 10 degree Centigrade, then the microwave
generating system is working.
5.2 MICROWAVE LEAKAGE TEST
5.2.1 TESTING EQUIPMENT
600cc beaker
Microwave meter
5.2.2 TESTING PROCEDURE
1. Place 275cc of water into the beaker and place it in the center of the oven.
2. Turn on the microwave oven by setting the cook time and start at full power.
3. Hold the probe of the microwave meter perpendicular to the surface of the oven
and scan it at the rate of 1 inch/sec.
4. Test the following areas for microwave leakage:
Door and control panel
All ventilation openings
All lockseams
Weld at bottom
Bottom plate
Oven foot

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5. Pull the door to the position at which the oven is just about to turn off due to the
interlock switch action, scan the door perimeter for microwave leakage.
6. Maximum allowable leakage is 4 mW/cm2.
7. Record all data.
5.2.3 OVEN MICROWAVE LEAKAGE REPAIR
If leakage figure is found to be above 5 mW/cm2, owner should be told not to use
the oven until it has been serviced. Service personnel should notify the
manufacturer immediately.
5.2.4 OPEN DOOR TEST
With the oven in operation state, open the oven door and check if the oven is still
operating. If so, the service personnel should tell the owner not to operate the
oven again and should notify the manufacturer immediately.
6. TROUBLE SHOOTING GUIDE
6.1 CAUTION AND IMPORTANCE
1. Before disassembling the oven, the oven power must be turned off. Remove the
power plug of the oven from the outlet and wait for at least 3 minutes.
2. When disassembling, service personnel should remove their watches and metal chains
from their hands. Never touch the high voltage components and wire.
3. Before checking or replacing, discharge the high voltage capacitor to oven chassis
grounded with an insulated wire. Make sure that the wire is grounded to chassis side
before short circuiting the capacitor terminal.
4. Do not measure high voltage with a common voltmeter.
6.2 MICROWAVE LEAKAGE
1. Refer to section 5.2 regarding microwave leakage. If the leakage is greater than 4
mW/cm2, it is necessary to repair the oven.
2. If leakage is found worst at control panel, ventilation openings or oven bottom, check
if there is any damaged parts or loose screws in the respective areas. If so, replace the
damaged parts and fasten the screws.

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3. If leakage is found worst around the door perimeter, adjust the interlock support or
change the door.
6.3 QUICK SERVICE REFERENCES
PROBLEM
POINTS TO CHECK
Cavity lamp does not light, but other
electrical components (e.g. turntable) are
working.
1. Lamp burnt.
2. Bad contact between lamp and lamp
socket.
Cavity lamp does not light, all other
electrical components also do not work.
1. Power plug not in good connection with
the socket. No power supply.
2. Fuse blown.
3. Bad contact between fuse and fuse
holder/clip.
4. Loose door hinge, door poorly adjusted,
interlock poorly adjusted; causing fuse
to be blown.
5. Short circuit within electrical circuit.
Lamp filament short, HV transformer
short, all causing fuse blown.
6. Bad contact in contacts or terminals of
power relay, primary and secondary
interlock switch.
7. HV diode break down.
Oven seems working, food does not cook
1. Defective magnetron (filament broken,
filament short to ground etc.).
2. Ground wire of HV transformer broken.
3. Filament wire short to ground.
4. Filament wire broken.
5. Bad contact in magnetron terminals.
6. Defective control boards.
7. HV diode break down, giving a hum
noise.
Oven cooks for a short while and stop.
1. Cooling fan jammed.
2. Cooling fan motor open circuit.
Turntable does not turn.
1. Defective turntable motor.
2. Turntable shaft deformed.
User circuit breaker activates.
1. High leakage in electrical components
(mostly motor).

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7. MAJOR COMPONENT TESTS
7.1 HV TRANSFORMER
1. Remove lead wire.
2. Measure the resistance of the winding using an ohm meter
3. Primary winding 3 ohm (approx.)
4. Secondary winding 100 ohm (approx.)
5. Filament winding 0 ohm (approx.)
7.2 HV CAPACITOR
1. Remove lead wire
2. Measure the resistance using an ohm meter set to R*1000
3. Terminal to terminal should momentary indicates several ohms but gradually
increases to infinite.
4. Terminal to case should show infinite.
7.3 HV DIODE
1. Remove lead wire.
2. Measure forward resistance, normal diode show continuity.
3. Measure reverse resistance, normal diode show infinite resistance.
7.4 MAGNETRON
1. Remove lead wire.
2. Install the magnetron gasket in the correct position. Check that the gasket is in
good condition.
3. Measure the resistance of the filament terminals. Normal magnetron should be
less than 1 ohm.
4. Measure the resistance between the filament terminal to chassis. Normal
magnetron should be infinite.
7.5 INTERLOCK SWITCH SYSTEM
IMPORTANCE: The installation of the interlock and monitor switches are
required by Federal regulations.