Sharp R-21JVF Service Manual - Page 16

R-21HT-F R-21JV-F PROCEDURE LETTER H TEST PROCEDURES COMPONENT TEST BLOWN MONITOR FUSE TEST 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. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary interlock switch and monitor switch according to the "TEST PROCEDURE" for those switches before replacing the blown monitor fuse. CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK RELAY, SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must be replaced with "monitor fuse and monitor switch assembly" part number FFS-BA015WRK0, even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised of a 20 ampere fuse and switch. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. NOISE FILTER I NOISE FILTER TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. N 4. Disconnect the lead wires from the terminal the noise filter. Using an ohmmeter, check between the terminals LINE CROSS CAPACITOR 0.22 F AC250V L FUSE 20A as described in the following table. If incorrect reading are obtained, replace the noise filter. NOISE SUPPRESSION COIL 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is LINE BYPASS CAPACITOR 0.003300 F / AC 125V LINE BYPASS CAPACITOR 0.003300 F / AC 125V installed. WHITE RED 8. Run the oven and check all functions. MEASURING POINT Between N and L Between terminal N and WHITE Between terminal L and RED INDICATION OF OHMMETER Open circuit Short circuit Short circuit J TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key Unit, and troubleshooting by unit replacement is described according to the symptoms indicated. Before testing, 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. 14