R-8000GK - Sharp Home Appliance Service Manual (repair manual). Page 13

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3. If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.

Check them and replace the defective parts and the high voltage fuse.

4. CARRY OUT 4R CHECKS.

CAUTION: ONLY REPLACE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE REPLACEMENT.

1. CARRY OUT 3D CHECKS.
2. Disconnect the leads from the terminals of noise filter.

Using an ohmmeter, check between the terminals as described in the
following table.

Between N and L

Approx. 680 k

Ω

Between terminal N and WHITE

Short circuit

Between terminal L and RED

Short circuit

If incorrect readings are obtained, replace the noise filter unit.

CARRY OUT 4R CHECKS.

1. CARRY OUT 3D CHECKS.
2. If the fuse 20A is blown, there is a shorts or grounds in electrical parts or wire harness Check then and replace

the defective parts or repaire the wire harness.

3. CARRY OUT 4R CHECKS.

1. CARRY OUT 3D CHECKS.
2. If the fuse F10A is blown when the door is opened, check the secondary interlock switch, relay RY1, relay

RY2 and monitor switch.

3. If the fuse F10A is blown by incorrect door switching, replace the defective switch(es) and the fuse F10A.
4. If the fuse F10A is blown, there is a shorts or grounds in electrical parts or wire harness.

Check them and replace the defective parts or repair the wire harness.

5. CARRY OUT 4R CHECKS.

CAUTION: ONLY REPLACE FUSE F10A WITH CORRECT VALUE REPLACEMENT.

FUSE

20A

N

L

LINE CROSS CAPACITOR   1.0

µ/AC275V 

NOISE SUPPRESSION COIL 

LINE BYPASS 
CAPACITOR
0.0047

µ/AC250V

LINE BYPASS
CAPACITOR
0.0047

µ/AC250V

RESISTOR   
10M    1/2W

RESISTOR   680K    1/2W

WHT

RED

NOISE FILTER

1. CARRY OUT 3D CHECKS.
2. A continuity check across the temperature fuse terminals should indicate a closed circuit unless the

temperature of the magnetron reaches approximately 150˚C. An open temperature fuse indicates overheating
of the magnetron. Check for restricted air flow to the magnetron, especially the cooling duct and cooling fan.

3. CARRY OUT 4R CHECKS.

CAUTION: IF THE TEMPERATURE FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE,

REPLACE TEMPERATURE FUSE.

1. CARRY OUT 3D CHECKS.
2. A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the

temperature of the thermal cut-out reaches approximately 170˚C. The thermal cut-out resets automatically
at approximately 155˚C. If thermal cut-out has opened under normal condition, replace the same item as in
the parts list.
An open thermal cut-out indicates overheating of the top heating element unit. Check for restricted air flow
to the top heat element  unit through the vent holes of the oven cavity, especially the heater duct upper and
convection fan.

3. CARRY OUT 4R CHECKS.

CAUTION: IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE,

REPLACE THERMAL CUT-OUT.