SHARP R390AW, R-390AK Service Manual

R-390AW R-390AK

SUPPLEMENTAL SERVICE MANUAL

SX712R390APW/

MICROWAVE OVEN

Miltiple Choice

POPCORN

MINUTE PLUS STOP 

CLEAR

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INDEX

START

MODELS

R-390AW R-390AK

R-390AW

In the interest of user-safety the oven should be restored to its original

condition and only parts identical to those specified should be used.

This is a supplemental Service Manual for Models R-390AW and R-390AK. The R-390AW is quite similar to model R-

390AK, with color changing.

And also this supplemental service manual contains update information for the R-390AK. Use this supplemental manual together with the Base Model Service Manual (Refer No. is S5708R390APK/) for complete operation, service information, etc..

TABLE OF CONTENTS

Page PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICE TO

AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ...................INSIDE FRONT COVER

BEFORE SERVICING ......................................................................................................INSIDE FRONT COVER

FOREWORD.....................................................................................................................INSIDE FRONT COVER

MICROWAVE MEASUREMENT PROCEDURE ...................................................................................................1

SCHEMATIC DIAGRAM ........................................................................................................................................ 2

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ..................................................................3

CPU UNIT CIRCUIT ..............................................................................................................................................6

PRINTED WIRING BOARD OF DISPLAY UNIT ...................................................................................................7

PARTS LIST FOR R-390AW .................................................................................................................................8

INFORMATION OF PARTS CHANGING FOR R-390AK ....................................................................................10

SHARP CORPORATION

This document has been published to be used for after sales service only. The contents are subject to change without notice.

R-390AW R-390AK

SERVICE MANUAL

MICROWAVE OVEN

R-390AW, R-390AK

FOREWORD

This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVENS, R-390AW, R-390AK.

It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory customer service.

Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and microwave radiation hazard.

This supplemental service manual contains update information only. Please refer to base model service manual (Refer No. is S5708R390APK/) for complete service information.

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY

(a) Do not operate or allow the oven to be operated with the door open. (b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other

microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse.

compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections.

(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and

transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner.

(e) A microwave leakage check to verify compliance with the Federal Performance Standard should be performed

on each oven prior to release to the owner.

BEFORE SERVICING

Before servicing an operative unit, perform a microwave emission check as per the Microwave Measurement Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS CORPORATION immediately @1-800-237-4277.

If the unit operates with the door open, service person should 1) tell the user not to operate the oven and

2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administration's Center for Devices and Radiological Health immediately.

Service personnel should inform SHARP ELECTRONICS CORPORATION of any certified unit found with emissions in excess of 4mW/cm2. The owner of the unit should be instructed not to use the unit until the oven has been brought into compliance.

R-390Aw R-390AK

MICROWAVE MEASUREMENT PROCEDURE

A. Requirements:

1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

2) Safety interlock switches Primary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

B. Preparation for testing: Before beginning the actual measurement of leakage, proceed as follows:

1) Make sure that the actual instrument is operating normally as specified in its instruction booklet. Important:

Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.

2) Place the oven tray in the oven cavity.

3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (68˚F) in the center of the oven cavity.

The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically nonconductive material such as glass or plastic. The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is measured accurately.

4) Set the cooking control on Full Power Cooking Mode

5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed,

replace it with 275 ml of cool water.

C. Leakage test:

Closed-door leakage test (microwave measurement)

1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.

2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on the meter.

3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal has been breached (eg., around the switches, indicator, and vents). While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed latch assembly.

4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2, and that the secondary interlock switch does turn the oven OFF before any door movement.

NOTE: After servicing, record data on service invoice and microwave leakage report.

R-390Aw R-390AK

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED.

2. HOME PAGE APPEARS ON DISPLAY.

THERMAL  CUT-OUT (OVEN)

CONTROL UNIT

120V AC 60 Hz

OUTER CASE SWITCH

MONITOR  FUSE

OL FM

OUTER CASE SWITCH

Figure O-1. Oven Schematic-Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED.

2. COOKING TIME PROGRAMMED.

3. VARIABLE COOKING CONTROL "100%".

4. "START" PAD TOUCHED.

OVEN LAMP

SECONDARY INTERLOCK SWITCH

THERMAL  CUT-OUT (MG.)

(RY-1)

TTM

TURN- TABLE MOTOR

COM.

(RY-2)

FAN  MOTOR

BAA1

PRIMARY INTERLOCK RELAY

DOOR SENSING SWITCH

AH SENSOR

POWER  TRANSFORMER

CAPACITOR

0.94µF

RECTIFIER

MAGNETRON

N.O.

MONITOR  SWITCH

120V AC 60 Hz

OUTER CASE SWITCH

THERMAL  CUT-OUT (OVEN)

CONTROL UNIT

MONITOR  FUSE

OL FM

OVEN LAMP

SECONDARY INTERLOCK SWITCH

THERMAL  CUT-OUT (MG.)

(RY-1)

TTM

TURN- TABLE MOTOR

COM.

(RY-2)

FAN  MOTOR

PRIMARY INTERLOCK RELAY

DOOR SENSING SWITCH

N.O.

MONITOR  SWITCH

Figure O-2. Oven Schematic-Cooking Condition

AH SENSOR

POWER  TRANSFORMER

CAPACITOR

0.94µF

RECTIFIER

MAGNETRON

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

CAUTION: DISCONNECT OVEN FROM POWER SUPPLY BEFORE REMOVING OUTER CASE.

DISCHARGE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING AFTER REMOVING OUTER CASE.

WARNING FOR WIRING

R-390Aw R-390AK

To prevent an electric shock, take the following manners.

1. Before wiring,

1) Disconnect the power supply.

2) Open the door and wedge the door open.

3) Discharge the high voltage capacitor and wait for 60 seconds.

2. Don’t let the wire leads touch to the following parts;

1) High voltage parts: Magnetron, High voltage transformer, High voltage capacitor and High voltage rectifier assembly.

2) Hot parts: Oven lamp, Magnetron, High voltage transformer and Oven cavity.

COOLING FAN MOTOR REMOVAL

REMOVAL

1. Disconnect oven from power supply and remove outer case.

2. Discharge high voltage capacitor.

3. Disconnect the wire leads from the fan motor.

4. Remove the magnetron from the waveguide flange, referring to "MAGNETRON REMOVAL".

5. Release the snap of the main wire harness from the fan duct.

6. Remove one (1) screw holding the fan duct assembly to oven cavity.

7. Release the main wire harness from the hole of the fan duct.

8. Release the fan duct from the waveguide flange.

9. Release the fan duct assembly from the oven cavity.

10.Remove the fan blade from the fan motor shaft according the following procedure.

1) Hold the edge of the rotor of the fan motor by using a pair of groove joint pliers.

CAUTION: * Make sure that any pieces do not enter the gap

between the rotor and the stator of the fan motor because the rotor is easily shaven by pliers and metal pieces may be produced.

* Do not touch the pliers to the coil of the fan motor

because the coil may be cut or injured.

* Do not disfigure the bracket by touching with the

pliers.

2) Remove the fan blade from the shaft of the fan motor by pulling and rotating the fan blade with your hand.

3) Now, the fan blade will be free.

CAUTION: * Do not reuse the removed fan blade because the

hole (for shaft) may be larger than normal.

3) Sharp edge: Bottom plate, Oven cavity, Waveguide flange, Chassis support and other metallic plate.

4) Movable parts (to prevent a fault) Fan blade, Fan motor, Switch, Switch lever, Open button.

3. Do not catch the wire leads in the outer case cabinet.

4. Insert the positive lock connector certainly until its pin is locked. And make sure that the wire leads should not come off even if the wire leads is pulled.

5. To prevent an error function, connect the wire leads correctly, referring to the Pictorial Diagram.

11.Remove the two (2) screws holding the fan motor to the fan duct.

12.Now, the fan motor is free.

INSTALLATION

1. Install the fan motor to the fan duct with the two (2) screws.

2. Install the fan blade to the fan motor shaft according the following procedure.

1) Hold the center of the bracket which supports the shaft of the fan motor on the flat table.

2) Apply the screw lock tight into the hole (for shaft) of the fan blade.

3) Install the fan blade to the shaft of fan motor by pushing the fan blade with a small, light weight, ball peen hammer or rubber mallet.

CAUTION: * Do not hit the fan blade strongly when installed

because the bracket may be disfigured.

* Make sure that the fan blade rotates smooth after

installation.

* Make sure that the axis of the shaft is not slanted.

3. Catch three holes of fan duct on three tabs of the waveguide flange.

4. Install the fan duct assembly to the oven cavity with the one (1) screw.

5. Insert the snap of the main wire harness to the hole of the fan duct and insert the main wire harness into the hole of the fan duct.

6. Install the magnetron and the chassis support to the oven cavity, referring to "Re-install of MAGNETRON REMOVAL".

7. Connect the wire leads to the fan motor, referring to the pictorial diagram.

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