R990K(W)
2 – 1
R990K(W)
Service Manual
CHAPTER 2.
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part of the high voltage circuit will result in
electrocution. High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage harness and High voltage fuse.
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge the high voltage capacitor.
WARNING: AGAINST THE CHARGE OF THE HIGH-VOLTAGE
CAPACITOR
The high-voltage capacitor remains charged about 60 sec-
onds after the oven has been switched off. Wait for 60 sec-
onds and then short-circuit the connection of the high-
voltage capacitor (that is, of the connecting lead of the
high-voltage rectifier) against the chassis with the use of
an insulated screwdriver.
Sharp recommend that wherever possible fault-finding is carried out
with the supply disconnected. It may, in some cases, be necessary to
connect the supply after the outer case has been removed, in this
event carry out 3D checks and then disconnect the leads to the pri-
mary of the power transformer. Ensure that these leads remain iso-
lated from other components and the oven chassis. (Use insulation
tape if necessary.) When the testing is completed, carry out 3D checks
and reconnect the leads to the primary of the power transformer.
REMEMBER TO CHECK 4R
1) Reconnect all leads removed from components during testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
Microwave ovens should not be run empty. To test for the presence of
microwave energy within a cavity, place a cup of cold water on the
oven turntable, close the door and set the microwave timer for two (2)
minutes. Set the power level to HIGH and push the START button.
When the two minutes has elapsed (timer at zero) carefully check that
the water is now hot. If the water remains cold carry out 3D checks and
reexamine the connections to the component being tested.
When all service work is completed and the oven is fully assembled, the microwave power output should be checked and microwave leakage test
should be carried out.
Summary of Contents for Carousel R-990K
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