Sharp R-1500AT, Service Manual

Page: 18 / 56

R1500AT
6 – 4
[8] H: WEAK POINT F1, F2 TEST
1. CARRY OUT 3D CHECKS.
2. If the weak point F1 or F2 is blown when the door is opened, check the primary interlock relay RY1, secondary interlock switches SW1, SW2 and
monitor switches SW3, SW4 according to the “TEST PROCEDURE” for those switches before replacing the blown weak point F1 or F2.
CAUTION: CAUTION: BEFORE REPLACING A BLOWN WEAK POINT F1 OR F2, TEST THE PRIMARY INTERLOCK RELAY RY-1, SECONDARY
INTERLOCK SWITCHES SW1, SW2, DOOR SENSING SWITCH SW5 AND MONITOR SWITCHES SW3, SW4 FOR PROPER OPERA-
TION.
3. If the weak point is blown, check the magnetron, high voltage capacitor, high voltage rectifier assembly, according to the “TEST PROCEDURE”
before replacing the blown weak point. Then replace the weak point.
4. CARRY OUT 4R CHECKS.
[9] I: WEAK POINT (FOR FAN MOTOR ) TEST
CARRY OUT 3D CHECKS.
If the weak point is blown, the fan motor or exhaust fan could be locked or there could be a shorts in the fan motor or exhaust fan. Check them and
replace the defective parts.
CARRY OUT 4R CHECKS.
CAUTION: Only replace weak point with the correct value replacement.
[10] J: WEAK POINT (IN NOISE FILTER) TEST
CARRY OUT 3D CHECKS.
If the weak point is blown, there could be a shorts or grounds in electrical parts or wire harness. Check them and replace the defective parts or repair
the wire harness.
CARRY OUT 4R CHECKS.
CAUTION: Only replace weak point with the correct value replacement.
[11] K: TEMPERATURE FUSE TEST
1. CARRY OUT 3D CHECKS.
2. A continuity check across the temperature fuse terminals should indicate a closed circuit unless the temperature of the temperature fuse reaches
specified temperature as shown below.
3. CARRY OUT 4R CHECKS.
CAUTION: IF THE TEMPERATURE FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE TEMPERATURE FUSE.
[12] L: MAGNETRON THERMISTOR TEST
1. CARRY OUT 3D CHECKS.
2. Disconnect the connector of the magnetron thermistor from the harness. Measure the resistance of each thermistor with an ohmmeter. Connect
the ohmmeter leads to the connector of each thermistor.
If the meter does not indicate above resistance, replace the thermistor.
3. CARRY OUT 4R CHECKS.
[13] M: EXHAUST THERMISTOR TEST
The exhaust thermistor can be checked by using the Special function (SF-6). Check the exhaust thermistor, referring to the pages of the Exhaust ther-
mistor check (SF-6).
If the display shows “OH”, the exhaust thermistor is normal. If the display shows “no”, the exhaust thermistor is abnormal and it should be replaced.
Open temperature Close temperature Display or
Condition
Check point
Magnetron temperature
fuse (1)
150 ° C Non resetable type
EE1
Magnetron (MG1) Failure:
Test magnetron (MG1) and fan motor.
Magnetron temperature
fuse (2)
EE2
Magnetron (MG2) Failure:
Test magnetron (MG2) and fan motor.
Magnetron temperature
fuse (1), (2)
EE3
Magnetron (MG1), (MG2) Failure: Test magnetron
(MG1), (MG2).
Check fan motor and ventilation opening.
Oven temperature fuse 120
°
C Non resetable type Oven shut off
Food has been burned in oven.
Temperature of oven inside is very high.
Room temperature Resistance
20
°
C Approx. 750K
Ω