Sharp R-21JCA-F Troubleshooting Guide, Test Procedure Possible Case Defective Parts, Problem

Page 11

R-21JCA-F

TROUBLESHOOTING GUIDE

Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.

When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the "Test Procedure "section.

IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, primary interlock relay (RY1), door sensing switch and secondary interlock switch before replacing the monitor fuse. If monitor fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA015WRK0 as an assembly.

IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases, be necessary to connect the power supply cord after the outer case has been removed, in this event,

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 the leads remain isolated from other components and oven chassis by using insulation tape.

6.After that procedure, reconnect the power supply cord.

When the testing is completed

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.Reconnect the leads to the primary of the power transformer.

5.Reinstall the outer case (cabinet).

6.Reconnect the power supply cord after the outer case is installed.

7.Run the oven and check all functions.

TEST PROCEDURE

POSSIBLE CASE

AND

DEFECTIVE PARTS

CONDITION

PROBLEM

 

Home fuse or circuit breaker blows when

OFF

power cord is plugged into wall outlet.

 

CONDITION

Monitor fuse blows when power cord is

 

 

plugged into wall outlet.

 

Oven lamp does not light, and fan motor

 

and antenna motor do not operate.

 

Oven does not go into cook cycle when

 

Light Up Dial turned.

 

Oven seems to be operating but little or

COOKING

no heat is produced in oven load. (Food

CONDITION

incompletely cooked or not cooked at all

 

at end of cook cycle.)

 

Oven goes into a cook cycle but

 

extremely uneven heating is produced in

 

oven load (food).

 

 

A

B

C

D

E

F

F

G

H

I

J

K

L

RE

RE

RE

RE

RE

CK

CK

CK

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE CAPACITOR

THERMAL CUT-OUT

SECONDARY INTERLOCK SWITCH

PRIMARY INTERLOCK SYSTEM

MONITOR SWITCH

MONITOR FUSE

NOISE FILTER

CONTROL PANEL

RELAY (RY2)

FOIL PATTURN ON P.W.B.

OVEN LAMP OR SOCKET

COOLING FAN MOTOR

ANTENNA MOTOR

SHORTED IN POWER CORD

SHORT OR OPENED WIRING

WRONG OPERATION

LOW VOLTAGE

DIRTY OVEN CAVITY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9

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Contents Model R-21JCA-F Before Servicing Dont Touch Before Servicing When the testing is completedLeakage test Microwave Measurement ProcedureRequirements Sharp Electronics Corporation Light Duty Commercial Microwave Oven 21JCA-F ForewordActual capacity for holding food is less SpecificationGeneral Information Maximum width, depth and height10 6 Oven DiagramCooking Condition OperationDescription of Operating Sequence OFF ConditionFM AM Figure O-1 Oven Schematic-OFF ConditionDescription and Function of Components Problem Troubleshooting GuideTest Procedure Possible Case Defective Parts Power Transformer Test Microwave Output PowerThermal CUT-OUT Test 145˚C Magnetron High Voltage Capacitor TestThermal CUT-OUT Test 125˚C Oven Primary Interlock Relay RY1 Door Sensing SwitchMonitor Switch Test Primary Interlock System TestNoise Filter Test Control Panel Assembly TestBefore testing Relay Test Test Procedures Letter Component TestSteps Occurrence Cause or Correction Description of LSI Touch Control Panel AssemblyPower source voltage +5V Pin No Signal Description Auto clear terminalPower source voltage Internal clock oscillation frequency input settingServicing Tools Other PrecautionsTouch Control Panel Servicing Servicing of Touch Control PanelSoldering Precautions for Using LEAD-FREE SolderUsing lead-free wire solder Employing lead-free solderOuter Case Removal Component Replacement and Adjustment ProcedurePower Transformer Removal Oven Lamp and Lamp Socket Removal Control Panel Assembly RemovalMagnetron Removal Rear View Positive Lock Connector NO-CASE Type RemovalAntenna Motor Removal Cooling FAN Motor RemovalRemoval Power Supply Cord ReplacementRe-install Door Parts Removal Removal Antenna Motor Shaft ReplacementAfter any service, make sure of the following Figure C-10. Stirrer Antenna Assembly Installation Installation of Ceramic ShelfHighvoltagecomponents PictorialDiagramCN-A3 Pin5mm Pitch Figure S-3. Printed Wiring Board Control Panel Parts Parts ListElectric Parts Cabinet PartsSCREWS,NUTS and Washers HOW to Order Replacement PartsDoor Parts MiscellaneousOven and Cabinet Parts Control Panel Parts Copyright 2005 by Sharp Corporation ALL Rights Reserved Packing and Accessories
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