14
- Disconnect the wires from the capacitor (8)
- Unscrew one screw (103) with the serrated washer (113) mounting the capacitor holder (4) with the HV diode
(7) and HV fuse (6) to the base plate (58)
- Remove the bracket with the capacitor and diode
- Remove the HV fuse holder (5)
Magnetron fan motor
- Make the steps outlined in the paragraph “Case”
- Disconnect the wires from the fan motor (13) and the noise filter (14)
- Unscrew the two screws (103) with the serrated washers (113) securing grounding wires (of the power cord and
noise filter) to the cavity (22), remove the power cord (51)
- Unscrew the two screws (104) mounting the noise filter (14) to the fan shroud (12) and remove the noise filter
(14)
- Unscrew the two screws (102), at the back of the oven, mounting the fan shroud (12) to the cavity (22) with the
power cord clip (52)
- Remove the magnetron fan blade (11) from the magnetron fan motor shaft (13)
- Unscrew the two screws (111) mounting the magnetron fan motor (13) to the fan shroud (12)
- Remove the fan motor
Door interlock
- Make the steps outlined in the paragraph “Control panel”
- Unscrew the two screws (103) with the serrated washers (113) mounting the microswitch mounting (42), re-
move the mounting
- Pull out the terminals of the microswitches (43) and the control microswitch (44)
- Remove the control microswitch (44) and microswitches (43) from the microswitches bracket (42)
4. TROUBLESHOOTING
Checking failure causes
Best practices consist in inspection.
Check the condition of the oven. Abnormalities include visible door deformation, broken door latch, door distor-
tion or excessive clearance between the door and the oven frame after closing.
Checking the microwave oven
•
Checking the insulation resistance of the oven
Measure the insulation resistance using a multimeter or megohm-meter, measured value shall not be lower than 2
mega-ohms. Otherwise, you shall immediately check parts for the presence of current leakage for the electric motor,
thermal circuit breaker, transformer, or capacitor.
•
Checking the microwave radiation leakage
Measure the microwave leakage value using a microwave leakage meter. Place a glass measuring cylinder with 275
ml of water in the centre of the glass turntable, inside the oven. Close the door; set the appliance at its maximum mi-
crowave power and adjust the cooking time to 3 minutes. Make measurements around the door gap, window holes,
and ventilation holes on the four sides of the oven using a measuring probe. During measurement, the speed of mov-
ing the probe shall be 25 mm per second, and the direction of measurement shall be consistent with the direction of
microwave leakage. The maximum value of the microwave leakage for each of the measurement locations must not
exceed 1 mW/cm
2
.
Methods of repairing major failures
Repair when a strong microwave leakage occurs. The main causes of microwave leakage are as follows:
••••
Deformed door, loosen or damaged hinge, resulting in inability to properly close the door.
••••
Dirt between the door and the oven.
••••
Large clearance between the door and the oven.
••••
Cracked mesh screen of the door cover.
••••
Visible damage of the oven case.
Before any repair, check if there occurs any of the reasons given above. If not, you can start the microwave oven.
Measure the microwave leakage as specified in the earlier paragraph. If the microwave leakage value exceeds the
limit, you have to adjust the door to remove the excessive play. If leakage still occurs, it should be measured close to
the magnetron. If in this place, the leakage value is higher, the oven shall be switched off and examined for proper
positioning of the copper mesh in the magnetron, and check if the magnetron screws are tightened firmly.
Steps to be performed after repairing a microwave oven.
After the repair, you shall perform a test operation of the oven. It can be operated only when it is shown that it is in
good condition with respect to safety, heating and defrosting functions. During this test operation, the oven must have
the following parameters:
