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R-509BK
TEST PROCEDURES
Procedure Letter
Component Test
E.
Continued
Open Monitor Fuse
1. Disconnect the power supply cord, and then remove outer case cabinet.
2. Open the door and block it open.
3. Discharge the high voltage capacitor.
4 If the monitor fuse is open, perform the tests for the primary interlock system, secondary interlock
switch and the monitor switch according to the procedure outlined in this section. Adjust or replace
the secondary interlock and door sensing switches.
5. Reconnect all leads removed from components during testing.
6. Re-install the outer case cabinet.
7. Reconnect the power supply cord after installing the outer case cabinet.
8. Run the oven and check all functions.
F
.
Temperature Fuses
1. Disconnect the power supply cord, and then remove outer case cabinet.
2. Open the door and block it open.
3. Discharge the high voltage capacitor.
4. A continuity check across either of the temperature fuse terminals should indicate a closed circuit
unless the temperature of the magnetron temperature fuse reaches 1 50°C or the oven cavity fuse
reaches 15OOC. An open magnetron temperature fuse indicates overheating of the magnetron as-
sembly while an open oven fuse indicates overheating of the oven cavity. If a temperature fuse
indicates an open circuit, exchange that temperature fuse and check for a restricted air duct, re-
stricted air flow to the magnetron and oven cavity through the vent holes of the oven cavity, espe-
cially the air duct and cooling fan assembly.
5. Reconnect all leads removed from components during testing.
6. Re-install the outercase cabinet.
7. Reconnect the power supply cord after installing the outer case cabinet.
8. Run the oven and check all functions.
G.
Touch Control Panel Assembly Test
The touch control panel consists of circuits including semiconductors
such as LSI, ICs, etc. There-
fore, unlike conventional
microwave ovens, proper maintenance can not be performed with only a
voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided into two
control units, Control Unit and Key Unit. Troubleshooting
by unit replacement is described according
to the symptoms indicated.
Before testing
1. Disconnect the power supply cord, and then remove outer case cabinet.
2. Open the door and block it open.
3. Discharge the 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 insu-
lated tape.
6. After that procedure, reconnect
the power supply cord.
13
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