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R-890SLM
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 fuse,
High voltage harness.
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.
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 power level to HIGH (100%). And set the microwave
timer for two (2) minutes. 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 re-examine 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.
2 - 1
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge the high voltage capacitor.
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 seconds after the oven has been
switched off. Wait for 60 seconds and then
short-circuit the connection of the high voltag
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 primary of the power
transformer. Ensure that these leads remain isolated 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.
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