Sharp R-210A Servicing, Troubleshooting Guide, Warning To Service Personnel, REMEMBER TO CHECK 3D

R-210A

Note: The ON/OFF time ratio does not exactly corre- spond to the percentage of microwave power,

because approx. 2 seconds are needed for heat- ing up the magnetron filament.

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts will result in electrocution.

High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage Fuse, High voltage harness.

REMEMBER TO CHECK 3D

1)Disconnect the supply.

2)Door opened, and wedged open.

3)Discharge 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-voltage capaci- tor (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.

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 power level to HIGH. 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.

TROUBLESHOOTING GUIDE

When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the "Test Procedure "section.

IMPORTANT: If the oven becomes inoperative because of a blown fuse 13A in the 1st. latch switch - 2nd. latch switch

-monitor switch circuit, check the 1st. latch switch, 2nd. latch switch and monitor switch before replacing the fuse 13A.

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