Sharp r-8580 manual Description and Function of Components

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R -8580

DESCRIPTION AND FUNCTION OF COMPONENTS

THERMISTOR

The thermistor is a negative temperature coefficient type. The temperature in the oven cavity is detected through the resistance of the thermistor, and then the CPU unit causes the heater relay to operate, thus the current to the convection heater is turned ON/OFF.

OVEN THERMAL CUT-OUT

The oven thermal cut-out located on the bottom side of the thermal protection plate is designed to prevent damage to the convection heater unit if an overheated condition develops in the tube due to cooling fan fail- ure, obstructed air ducts, dirty or blocked air intake, etc. Under normal operation, the oven thermal cut-out re- mains closed. However, when abnormally high tem- peratures are reached within the heater unit, the oven thermal cut-out will open, causing the oven to shut down.

When the oven has cooled temperature, the oven thermal cut-out closes.

MONITOR SWITCH

The monitor switch is mounted on the upper latch hook. It is activated (the contacts opened) by the up- per latch head when the door is closed. The switch is intended to render the oven inoperative by means of blowning the fuse when the contacts of the common and normal open contacts of upper latch switch fail to open when the door is opened.

Functions:

1.When the door is opened, the monitor switch con- tacts close (to the ON condition) due to their being normally closed. At this time the the common and normal open contacts of upper latch switch are in

the OFF condition (contacts open) due to their being normally open contacts switch.

2.As the door goes to a closed position, the monitor switch contacts are first opened and then the common and normal open contacts of upper latch switch close. (On opening the door, each of these switches operate inversely.)

3.If the door is opened during cooking, and the common and normal open contacts of upper latch switch fail to open, the monitor fuse blows simul- taneously with closing of the monitor switch con- tacts.

CAUTION:BEFORE REPLACING A BLOWN FUSE TEST THE UPPER LATCH SWITCH AND

MONITOR SWITCH FOR PROPER

OPERATION.(REFER TO CHAPTER “TEST PROCEDURE”).

AFTER REPLACING FUSE ALSO REPLACE MONITOR SWITCH.

STOP SWITCH

The stop switch is activated by the lower latch head. When the door is opened while the oven is in cook cycle, the stop switch contacts open to de-energize the relay(RY-l,RY-2,RY-3,RY-4,RY-5).

Then the cook cycle is stopped.

UPPER AND LOWER LATCH SWITCHES

The lower latch switch is mounted in the lower latch hook and the upper latch switch is mounted in the upper latch hook. They are activated by the latch heads on the door. When the door is opened, the switches interrupt the’crrcuit to all components except CPU unit and relay unit and oven lamp. A cook cycle cannot take place until the door is firmly closed thereby activating both interlock switches.

P

’UPPER

A LATCH HOOK

Figure D-l. Upper Latch Switch, Lower Latch

Switch, Monitor Switch and Stop Switch

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Contents Sharp Convection Microwave Oven Microwave RadiationSharpcorporatkn OSAKA, Japan 8580Specification Product DescriptionAuto-TouchTM Control Panel OFF Condition OperationDescription of Operating Sequence Cooking ConditionPreheating Condition Convection Cooking ConditionAutomatic MIX Cooking Condition Convection Cooking ConditionEasy Defrost Cooking Sensor Cooking ConditionCompu Cook Cooking SequenceFigure O-l. Oven Schematic-OFF Condition 240V-50Hz G-4Figure O-3. Oven Schematic-Convection Cooking Condition Description and Function of Components Convection Cooking System Convection HeaterDamper OPEN-CLOSE Mechanism Servicing Problem Possible Cause Test Procedure CorrectionOFF Condjtion Problem Possible Cause Test Procedure or Correction Nents Defective Convection Heater Procedure RelayRY4 Unit Test Procedures Letter Component Magnetron Assembly Test Microwave Output PowerSwitch Test Procedure Letter Test Procedures CONT’D Component TestPower Transformer Test High Voltage Rectifier and Rectifier TestTEMP. Fuse Test Test Procedures CONT’D Letter Component Monitor Switch TestBlown Fuse Thermal CUT-OUTThermistor Test Procedure LetterDamper Switch Test Damper Motor TestTest Procedures CONT’O Letter Component Relay Unit Relay Symbol Operational Connected Components VoltageKEY Unit Test Checking the initial sensor cooking condition Testing Method for AH Sensor AND/OR Control UnitWater load cooking test Sensor Dummy Resistor Circuit Steps Occurance Cause or CorrectionOutline of Touch Control Panel Touch Control Panel AssemblyLSI Description of LSJ LSI IZA096DRKev strobe siqnal Seqment Data signalSeqment Data Siqnal Internal clock oscillation frequency input settinqPower source voltage Signal to SoundSignal svnchronized with commercial source frequencv50Hz Magnetron High-voltaae Circuit driving SignalSignal cominq from touch kev Damper motor relav driving signalInput signal which communicates the door open/close Signal coming from touch keyRI4 Temperature measurement input Oven ThermistorSensor Inuut Terminal For Manufacture TestAbsolute Humidity Sensor CircuitShapes of Electronic Components Other PrecautionsServicing Servicing of Touch Control PanelHigh Voltage Capacitor Removal Component Replacement and Adjustment ProcedurePower Transformer Removal Turntable Motor AND/OR Coupling RemovalConvection Motor Removal Magnetron RemovalCooling FAN Motor Removal Damper Upper Latch Switch / Monitor Switch RemovalLower Latch Switch and Stop Switch Removal RemovalControl Panel Assembly and CPU Unit Removal CPU Unit and KEY UnitDoor Replacement Door Replacement and AdjustmentDoor Adjustment Microwave Measurement Preparation for TestingRequirement 11II II II II OIL 8580 Figure S-3. Printed Wiring Board II IParts List AY AK AF AHQ8L RR-DZ561PDREOAT AH FOVN-A090WRYO AG AD 11 AA 13 AA Ii AA Replacement Parts List 8580 Control Panel Parts Door Assembly Miscellaneous ‘Y \‘\Packing and Accessories 8580 8580 Sharp
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