Troubleshooting and Testing
3-15
Procedure
Letter
Y
Component Test
PROCEDURES TO BE TAKEN WHEN THE FUSE 1 ON THE PRINTED WIRING BOARD (PWB)
IS OPEN.
To protect the electronic circuits, this model is provided with a fuse added to the primary on the PWB.
1. Fuse 1 check and repairs.
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. If the Fuse 1 is blown, replace it.
5. Make a visual inspection of the varistor. Check for burned damage and examine transformer
with a tester for the presence of layer short-circuit (check the primary coil resistance which is
approximately 275 ± 10%). If any abnormal condition is detected, replace defective parts.
6. Reconnect all leads removed from components during testing.
7. Re-install the outer case (cabinet).
8. Reconnect the power supply cord after the outer case is installed.
9. Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if indicator does not light up after above check and
repairs are finished.
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
5. Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
6. After that procedure, re-connect the power supply cord.
7. Follow the troubleshooting guide given below for repair.
8. Disconnect the power supply cord, and then remove outer case.
9. Open the door and block it open.
10. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
11. Reconnect all leads removed from components during testing.
12. Re-install the outer case (cabinet).
13. Reconnect the power supply cord after the outer case is installed.
14. Run the oven and check all functions.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 The rated AC voltage is not present to power Check supply voltage and oven power cord.
terminal of CPU connecter (CN-D).
2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and repair.
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