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Sharp R-1880LS Service Manual

Over the range microwave oven.
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In the interest of user-safety, the oven should be restored to its original condition and only parts identical to those specifi ed should be
used.
WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and current,
contact with following parts may result in a severe, possibly fatal, electrical shock. (High Voltage Capacitor, High Voltage Power
Transformer, Magnetron, High Voltage Rectifi er Assembly, High Voltage Harness etc..)
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY . ......................................................................
WARNING TO SERVICE PERSONNEL .................................................................................................................................6
FOREWORD AND WARNING ................................................................................................................................................7
PRODUCT SPECIFICATIONS .................................................................................................................................................8
GENERAL INFORMATION . ...................................................................................................................................................8
OPERATION . ...........................................................................................................................................................................11
TROUBLESHOOTING GUIDE . .............................................................................................................................................19
TEST PROCEDURE . ...............................................................................................................................................................
TOUCH CONTROL PANEL ASSEMBLY .............................................................................................................................33
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ..............................................................................40
PICTORIAL DIAGRAM .........................................................................................................................................................49
LSI UNIT CIRCUIT ................................................................................................................................................................50
PRINTED WIRING BOARD ..................................................................................................................................................51
PARTS LIST . ...........................................................................................................................................................................5
PACKING AND ACCESSORIES . ...........................................................................................................................................57
This document has been published to be used for after sales service only. The contents are subject to change without notice
(IN USA):
Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135
(IN CANADA):
Head Offi ce: 335 Britannia Road East, Mississauga, Ontario L4Z 1W9
SERVICE MANUAL
CONVECTION
MICROWAVE
Sensor
Minute
Convec
Preheat
Popcorn
Plus
Low Mix
High Mix
Keep
Power
Bake
Roast
Warm
Level
Slow
Sensor
Broil
Defrost
Cook
Reheat
1 Cake
Sensor
Bake
2 Brownies
3 Muffins
Cook
4 Pizza
1 Baked Potatoes
1 Poultry
2 Frozen Veg.
Roast
2 Chicken Pieces
3 Fresh Veg. - soft
3 Turkey Breast
4 Fresh Veg. - hard
4 Pork Loin
5 Frozen Entrees
6 Hot Dogs
1 Hamburgers
7 Bacon
2 Chicken Breast
8 Fish, Seafood
Broil
3 Steaks
4 Pork Chops
100°F
150°F
275°F
300°F
325°F
1
2
3
4
5
350°F
375°F
400°F
425°F
450°F
6
7
8
9
0
Turntable
Custom
Clock
On/Off
Help
Kitchen
Stop
START
Timer
Clear
Touch On
Fan
Light
Hi/Lo
Hi/Lo
C O N V E C T I O N M i c r o w a v e

TABLE OF CONTENTS

SHARP ELECTRONICS CORPORATION
SHARP CORPORATION
SHARP ELECTRONICS OF CANADA LTD.
(905) 890-2100
OVER THE RANGE
MICROWAVE OVEN
R-1880LS/LST
MODEL
Note: R-1880LST is the same as the R-1880LS, only the packing is different.
It is shipped on pallets for Recreational Vehicle distributors.
1
R-1880LS/LST
S66M263R1880L
Page
.

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   Summary of Contents for Sharp R-1880LS

  • Page 1: Table Of Contents

    PARTS LIST ....................................5 PACKING AND ACCESSORIES ............................57 This document has been published to be used for after sales service only. The contents are subject to change without notice SHARP ELECTRONICS CORPORATION (IN USA): Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135 SHARP CORPORATION (IN CANADA): SHARP ELECTRONICS OF CANADA LTD. Head Offi ce: 335 Britannia Road East, Mississauga, Ontario L4Z 1W9...
  • Page 2: Precautions To Be Observed Before And During Servicing To Avoid Possible Exposure To Excessive Microwave Energy

    R-1880LS/LST PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPO- SURE 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 () 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. (c) Before turning on microwave power for any service test or inspection within the microwave generating compart- ments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and con- nections. (d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and trans- mission 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.
  • Page 3 R-1880LS/LST NOTES:...
  • Page 4 R-1880LS/LST MICROWAVE MEASUREMENT PROCEDURE (USA) A. Requirements: 1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm 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/cm at any point 5cm or more from the external surface of the oven. ) 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/cm 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 micro- wave ovens, 1 CFR 1030.10(c)(3)(i), must be used for testing. ) Place the oven tray in the oven cavity. 3) Place the load of 75±15 ml (9.8 oz) of tap water initially at 0±5½C (68½F) in the center of the oven cavity.
  • Page 5 R-1880LS/LST MICROWAVE MEASUREMENT PROCEDURE (CANADA) After adjustment of the door switches are completed individually or collectively, switch test and microwave leakage test must be per- formed with survey instrument and test result must be confirmed to meet the requirement of the performance standard for microwave ovens as undermentioned. A. Requirements: Every microwave oven shall function in such a manner that when the oven is fully assembled and operating with it's service controls and user controls adjusted to yield the maximum output, the leakage radiation, at all points at least 5 cm. from the external surface of the oven, does not exceed: 1) 1.0mW/cm with the test load of 75 ± 15 ml of water at an initial temperature 0 ±5 ) 5.0mW/cm when the outer enclosure is removed with a test load of 75 ± 15 ml of water at an initial temperature 0±5 3) 5.0mW/cm without a test load. 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 CSA and NHW performance standard for microwave ovens must be used for testing recommended instruments are , NARDA 8100 and NARDA 800. ) Place the oven tray in the oven cavity.
  • Page 6: Warning To Service Personnel

    R-1880LS/LST WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Trans- former, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. Read the Service Manual carefully and follow all in- structions. Don't Touch ! Danger High Voltage Before Servicing 3. Discharge high voltage capacitor. 4. Reconnect the leads to the primary of the power transformer.
  • Page 7 Voltage Rectifier Assembly, High Voltage Harness; If provided, Vent Hood, Fan assembly, Cooling Fan Motor. All the parts marked “*” on parts list are used at voltages more than 50V. Removal of the outer wrap gives access to voltage above 50V. SHARP ELECTRONICS CORPORATION SHARP PLAZA, MAHWAH, NEW JERSEY 07430-2135...
  • Page 8: General Information

    R-1880LS/LST SPECIFICATION ITEM DESCRIPTION Power Requirements 10 Volts / 13. Amperes (Microwave), 13. Amperes (Convection) - [UL Rating] 116 Volts / 13. Amperes (Microwave), 13. Amperes (Convection) - [CSA Rating] 60 Hertz Single phase, 3 wire grounded Power Output 850 watts (IEC-705 TEST PROCEDURE) Operating frequency of 450MHz Convection Power Output 1400 watts Case Dimensions Width 9-15/16" Height 16-11/3" Depth 15- 9/3" Cooking Cavity Dimensions Width 17-1/8" Height 8-1/16" 1.1 Cubic Feet Depth 13-13/16" Hood lamp  bulbs, 0W x , Incandescent light bulbs Hood fan Horizontal discharge 30 C.F.M. , Vertical discharge 40 C.F.M. , Control Complement Touch Control System Clock ( 1:00 - 1:59 ) Timer (0 - 99 min. 99 seconds) Microwave Power for Variable Cooking Repetition Rate; P-HI ............. Full power throughout the cooking time P-90................. approx. 90% of Full Power P-80................. approx. 80% of Full Power P-70................. approx. 70% of Full Power P-60.................
  • Page 9: Oven Diagram

    R-1880LS/LST Electrical Requirements The oven is equipped with a 3-prong grounding plug. DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE GROUNDING PIN FROM THE PLUG. The power supply cord and plug must be connected to a separate 10 Volt AC, 60 Hz, 15 Amp. or more branch circuit, using a grounded receptacle. The receptacle should be located inside the cabinet directly above the Microwave Oven/Hood system mounting location. 1. Oven door with see-through window. Grounded 3-Pronged Plug Receptacle Box Grounding Pin 3-Pronged Receptacle OVEN DIAGRAM . Door hinges. 3. Sirrer cover. 4. Turntable motor shaft.
  • Page 10: Control Panel

    R-1880LS/LST CONTROL PANEL CONVECTION MICROWAVE Sensor Minute Convec Preheat Popcorn Plus Low Mix High Mix Keep Power Bake Roast Warm Level Slow Sensor Broil Defrost Cook Reheat 1 Cake Sensor 2 Brownies Bake Cook 3 Muffins 4 Pizza 1 Baked Potatoes 1 Poultry 2 Frozen Veg.
  • Page 11: Operation

    R-1880LS/LST OPERATION DESCRIPTION OF OPERATING SEQUENCE monitor switch contacts first open, and then the contacts The following is a description of component functions during of the secondary and third door switch close. oven operation. If the primaryswitch, secondary switch and secondary interlock OFF CONDITION relay fail with their contacts closed when the door is opened, the closing of the monitor switch contacts will form a short circuit Closing the door activates the door sensing switch and secondary through the monitor fuse, secondary switch ,third door switch and interlock switch. (In this condition, the monitor switch contacts primary interlock relay, causing the monitor fuse to blow. are opened.) When oven is plugged in, 10 volts A.C. is supplied to the control POWER LEVEL P-0 TO P-90 COOKING unit. (Figure O-1). When Variable Cooking Power is programmed, the 10 volts 1. The display will show "Welcome".
  • Page 12: Sensor Cooking Condition

    R-1880LS/LST 5. Now, the oven is in the convection cooking condition. sends a signal to the LSI on the control unit de-energizing the 6. When the oven temperature reaches the selected temperature, relay (RY6) and opening the circuit to the damper motor. the following operations occur: 3. The coil of heater relay (RY3) is energized by the control 6-1. The power supply voltage is alternated to the heating unit and the main supply voltage is applied to the heating element and power transformer. element. 6-. The heating element operates through the heater relay 4. When the oven temperature reaches the selected preheat...
  • Page 13 R-1880LS/LST The time of supplementary cooking is determined by experiment weight by touching the Number pads. When the START pad is with each food category and inputted into the LSI. touched, the following operations occur: An example of how sensor works: 1. The COOK indicator will light and the CONV or MIX indicator will light. . The cooking time will appear on the display and start counting down to zero. The cooking time is adjusted automatically according to the weight of the food. 3. The shut-off relays (RY1, RY4, RY5 and RY7) are energized, 1. Potatoes at room temperature. Vapor is emitted very slowly. turning on the oven lamp, turntable motor, cooling fan motor and convection motor. The power supply voltage is applied to the heating element. 4. Now, the oven is in the convection cooking mode or A utomatic Mix Cooking condition. 5. When the oven temperature has reached the programmed convection temperature, the oven goes into the programmed cooking mode.
  • Page 14 R-1880LS/LST detected vapors and initiated a sensor cooking cycle. 3. RE-CIRCULATION (INSIDE VENTING) This is because the operation of the convection fan The air handing is same as VERTICAL VENTING except would interfere with the AH sensor's vapor detection. that the final air discharge is directed horizontally through the upper front of the oven into the kitchen. IN this case, the...
  • Page 15 R-1880LS/LST SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. . CLOCK APPEARS ON DISPLAY. SCHEMATIC DIAGRAM (DOOR CLOSED COOK OFF CONDITION) MAGNETRON SECONDARY MONITOR TEMPERATURE INTERLOCK FUSE FUSE (20A) SWITCH BLK,BRN CONTROL UNIT THIRD DOOR SWITCH MONITOR SWITCH BRN,PNK DOOR HOOD FAN SENSING DAMPER THERMAL THERMISTOR SWITCH SWITCH CUTOUTS 120VAC (CONV.
  • Page 16 R-1880LS/LST SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. . CONVECTION PAD TOUCHED. 3. DESIRED TEMP. TOUCHED. 4. START PAD TOUCHED. MAGNETRON SECONDARY TEMPERATURE MONITOR INTERLOCK FUSE FUSE (20A) SWITCH BLK,BRN CONTROL UNIT THIRD DOOR SWITCH MONITOR SWITCH BRN,PNK DOOR HOOD FAN DAMPER SENSING THERMAL THERMISTOR SWITCH SWITCH CUTOUTS 120VAC (CONV. SIDE) POWER NOISE...
  • Page 17: Description And Function Of Components

    R-1880LS/LST DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM switch and secondary switch contacts fail to open, the monitor fuse blows simultaneously with closing of the monitor switch The door is opened by pushing the open button on the control contacts. panel, refer to the Figure D-1. CAUTION: BEFORE REPLACING A BLOWN MONITOR When the open button is pushed, the open button pushes up the FUSE, TEST THE SECONDARY INTERLOCK open lever, and then the open lever pushes up the latch head. The RELAY, S ECONDARY S WITCH, D OOR S ENSING latch heads are moved upward and released from latch hook. Now SWITCH, MONITOR SWITCH AND PRIMARY the door will open. SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").
  • Page 18: Convection Cooking System

    R-1880LS/LST The hood lamps are mounted at the hood lamp angle on the base unit and shut-off relay (RY6) is turned off. cover. When the hood lamp button is pushed, the hood lamp relay 1-5. The 10 volts A.C. to the damper motor is removed and (RY8) contacts close turning both hood lamps on. the motor turns off. . When oven is microwave cooking: HEATING ELEMENT Damper is in the open position. 3. When oven is convection cooking: The heating element is located at the left side of the oven cavity. 3-1. Damper motor is energized by touching the convection, It is intended to heat air driven by the convection fan. The heated temperature, number and START pads. air is kept in the oven and force-circulated and reheated by the 3-. When damper is in the closed position (damper switch is heating element. OFF), its signal is sensed by the control unit, and shut-off relay (RY6) is de-energized. CONVECTION COOKING SYSTEM 3-3. The damper is held in the closed position during the This oven is designed with a hot air heating system where food is convection cooking operation.
  • Page 19: Troubleshooting Guide

    R-1880LS/LST TROUBLESHOOTING GUIDE Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is con- nected. 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 secondary switch, door sensing switch, secondary interlock relay(RY), primary switch and monitor switch, before replacing the monitor fuse. If the moni- tor fuse is replaced, the monitor switch and primary switch must also be replaced. Use part FFS-BA018/KIT 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. . Open the door and block it open. 3. Discharge high voltage capacitor.
  • Page 20 R-1880LS/LST TROUBLESHOOTING GUIDE 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. CK = Check / RE = Replace A B C D E F G H I J K L TEST PROCEDURE POSSIBLE CAUSE AND DEFECTIVE PARTS CONDITION PROBLEM Home fuse blows when power cord is plugged into wall receptacle. Monitor fuse blows when power cord is plugged into wall receptacle. Display does not illuminate when power cord is first plugged into wall receptacle. Display does not operate properly when STOP/CLEAR key is touched. (The time of day should appear on the display with beep sound during normal condition.) OFF CONDITION Oven lamp does not light with door is opened. Hood fan motor operates when power cord is first plugged into wall receptacle. ο ο Temperature of oven base seems more than 140 F (60 C) because of operation of the range below. But hood fan motor does not turn on automatically. (Normally, food fan motor should be operating at low speed.)
  • Page 21 R-1880LS/LST IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, primary interlock relay, 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-BA018/KIT as an assembly. M N O P Q R S S S S S S S S S S U V RE RE RE RE CK CK RE CK RE RE CK C K W...
  • Page 22 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER MAGNETRON ASSEMBLY TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should indicate less than 1 ohm. 5. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground. This test should indicate an infinite resistance. If there is little or no resistance the magnetron is grounded and must be replaced. 6. Reconnect all leads removed from components during testing.
  • Page 23 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER HIGH VOLTAGE RECTIFIER TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals and observe, reverse the leads to the rectifier terminals and observe meter reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions, the rectifier is probably defective and should be replaced. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. NOTE: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 HIGH VOLTAGE CAPACITOR TEST 1. Disconnect the power supply cord, and then remove outer case.
  • Page 24 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER PRIMARY INTERLOCK RELAY (RY) 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect two () wire leads from the male tab terminals of the Primary Interlock Relay. Check the state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay contacts are closed, replace the circuit board entirely or the relay itself. 5. Reconnect all leads removed from components during testing. 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. MONITOR SWITCH TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Before performing this test, make sure that the primary interlock switch and the secondary interlock relay are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (NC) terminal. Check the monitor switch operation by using the ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When the monitor switch actuator is pushed by a screw driver through the lower latch hole on the front plate of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed in), the meter should indicate an open circuit. If improper operation...
  • Page 25 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER BLOWN MONITOR FUSE 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary interlock switch and monitor switch according to the "TEST PROCEDURE" for those switches before replacing the blown monitor fuse. CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK RELAY, SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must be replaced with "monitor fuse and monitor switch assembly" part number FFS-BA018/KiT, even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised of a 0 ampere fuse and switch. 5. Reconnect all leads removed from components during testing. 6. Re-install the outer case (cabinet).
  • Page 26 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER HOOD FAN MOTOR TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. If the motor does not turn, touch the Vent button once (set hood fan motor power "HIGH") and check voltage between pins "1" and "" (Blue and Black wires) of the 6 pin connector. If 10 Volts appear and the hood capacitor is good, replace the hood fan assembly. If 10 Volts does not appear, check the motor circuit. The resistance values of motor terminals are as follows: Resistance between; BLU (1) YLW (4) = 0 ohm (Shorted) BLK (2) YLW (4) = 32 ohm HOOD...
  • Page 27 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER CHECKING TEMPERATURE IN THE CONVECTION MODE 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. It is difficult to measure the exact temperature in the convection oven. A n accurate thermocouple type temperature tester must be used. A low priced bi-metal type thermometer is not reliable or accurate. The temperature should be checked with outer case cabinet installed, approx. 5 minutes after preheat temperature is reached (audible signal sounds four times). The temperature experienced may be approx. 30 F more or less than indicated on the display, however, in most cases the food cooking results will be satisfactory. Difference in power supply voltage will also affect the oven temperature. 5. Reconnect all leads removed from components during testing. 6. Re-install the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike...
  • Page 28 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER TOUCH CONTROL PANEL ASSEMBLY TEST . Control Unit. The following symptoms indicate a defective control unit. Before replacing the control unit, perform the Key unit test (Procedure R) to determine if control unit is faulty. -1 In connection with pads. a) When touching the pads, a certain group of pads do not produce a signal. b) When touching the pads, no pads produce a signal. - In connection with indicators a) At a certain digit, all or some segments do not light up. b) At a certain digit, brightness is low. c) Only one indicator does not light. d) The corresponding segments of all digits do not light up; or they continue to light up. e) Wrong figure appears. f) A certain group of indicators do not light up. g) The figure of all digits flicker. -3 Other possible problems caused by defective control unit.
  • Page 29 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER RELAY TEST 1. Disconnect the power supply cord, and then remove outer case. . 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 these leads remain isolated from other components and oven chassis by using insulation tape. 6. After that procedure, re-connect the power supply cord. 7. Remove the outer case and check voltage between Pin No. 5 of the 3-pin connector (A) and the common terminal of the relay RY1 on the control unit with an A.C. voltmeter. The meter should indicate 10 volts, if not check oven circuit. Relay Test These relays are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation. DC. voltage indicated....Defective relay. DC. voltage not indicated..Check diode which is connected to the relay coil. If diode is good, control unit is defective. RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS RY1 Approx. 4.0V D.C. Oven lamp RY(COOK) Approx. 4.0V D.C.
  • Page 30 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD PWB IS OPEN To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB, this foil pattern acts as a fuse. 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. If the foil pattern is open, follow the troubleshooting guide given below for repair. Problem: POWER ON, indicator does not light up. STEPS OCCURRENCE CAUSE OR CORRECTION The rated voltage is not applied between Pin Check supply voltage and oven main unit. No. 5 of the 3-Pin connector (A) and the terminal of the relay RY1.
  • Page 31 R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER should be installed and screws tightened. (1) Fill approximately 00 milliliters (7. oz) of tap water in a 1000 milliliter measuring cup. () Place the container on the center of tray in the oven cavity. (3) Close the door. (4) Touch SENSOR COOK pad. And touch the number pad 1. And touch the start pad. The oven will operate for the first 3 seconds, without generating microwave energy. NOTE: ERROR will appear if the door is opend or STOP/CLEAR pad is touched during first stage of sensor cooking. (5) After approximately 3 seconds, microwave energy is produced, oven should turn off after water is boiling (bubling). If the oven does not turn off, replace the AH sensor or check the control unit, refer to explanation below. TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor. (1) Disconnect oven from power supply and remove outer case. () Open the door and block it open. (3) Discharge the high voltage capacitor. (4) Remove the AH sensor. (5) Install the new AH sensor. (6) Reconnect all leads removed from the components during replacing. (7) Re-install the outer case. (8) Reconnect the oven to the power supply and check the sensor cook operation proceed as follows: 9-1. Fill approximately 00 milliliters (7. oz) of tap water in a 1000 milliliter measuring cup. 9-. Place the container on the center of tray in the oven cavity. 9-3. Close the door. 9-4. Touch SENSOR COOK pad. And touch the number pad 1. And touch the start pad. 9-5. The oven will turn off automatically after the water is boiling (bubling).
  • Page 32: Test Procedures

    R-1880LS/LST TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER NOISE FILTER TEST 1. Disconnect the power supply cord, and then remove outer case. . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect the leads to the primary of the power transformer. 5. Using an ohm-meter, check between the terminals as described in the following table: NOISE FILTER UNIT MONITOR FUSE NOISE SUPPRESSION COIL LINE CROSS CAPACI- 0.22uF/ AC 250V LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR 0.0033uF/ AC...
  • Page 33: Touch Control Panel Assembly

    R-1880LS/LST TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL 3) Synchronizing Signal Circuit The touch control section consists of the following units as shown in the touch control panel circuit. The power source synchronizing signal is available in order to compose a basic standard time in the clock circuit. It in- (1) Key Unit corporates a very small error because it works on commercial () Control Unit frequency. 4) ACL Circuit The principal functions of these units and the signals communicated among them are explained below. A circuit to generate a signals which resetting the LSI to the initial state when power is applied. Key Unit 5) Buzzer Circuit The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P00 - P06. The buzzer is responds to signals from the LSI to emit When a key pad is touched, a signal is completed through the key audible sounds (key touch sound and completion sound). unit and passed back to the LSI through AN1 and R4 - R7 to 6) Temperature Measurement Circuit : Oven perform the function that was requested.
  • Page 34: Description Of Lsi

    R-1880LS/LST DESCRIPTION OF LSI LSI(IZA719DR) The I/O signals of the LSI(IZA719DR) are detailed in the following table. Pin No. Signal Description VCC Connected to GND. Anode (segment) of Fluorescent Display illumination voltage: -31V. VEE Vp voltage of power source circuit input. Power source voltage:-5V. AVSS VC voltage of power source circuit input. Reference voltage input terminal. VREF A reference voltage applied to the A/D converter in the LSI. Connected to GND.(0V) AN7 Used for initial balancing of the bridge circuit (absolute humidity sensor). This input is an analog input terminal from the AH sensor circuit, and connected to the A/D converter built into the LSI. AH sensor input.
  • Page 35 R-1880LS/LST Pin No. Signal Description Convection motor driving signal. P50 OUT During cooking To turn on and off shut-off relay(RY7). "L" level during (Convection) CONVECTION; "H" level otherwise. H : GND Hood lamp driving signal. P47 OUT To turn on and off relay(RY8). "L" level: During Hood lamp ON. "H" level: During Hood lamp OFF. H : GND Hood motor driving signal. P46 OUT To turn on and off relay(RY9). "L" level: During Hood motor ON. "H" level: During Hood motor OFF. Hood motor high / low driving signal.
  • Page 36 R-1880LS/LST Pin No. Signal Description Output to control oscillation input of XIN. Power source voltage:-5V. VSS VC voltage of power source circuit input. Signal coming from touch key. P7 When any one of G1 line keys on key matrix is touched, a corresponding signal will be input into P7. When no key is touched, the signal is held at "L" level. Signal similar to AN1. P6 When any one of G11 line keys on key matrix is touched, a corresponding signal will be input into P6. Signal similar to P27. P5 When any one of G10 line keys on key matrix is touched, a corresponding signal will be input into P5. Signal similar to P27. P4 When any one of G9 line keys on key matrix is touched, a corresponding signal will be input into P4.
  • Page 37 R-1880LS/LST Pin No. Signal Description while one of G line keys on key matrix is touched. Segment data signal. P00 OUT Signal similar to P55. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to AN1 and P7 - P4 terminal while one of G1 line keys on key matrix is touched. Segment data signal. 57-59 P37-P35 OUT Signal similar to P55. 60-64 P34-P30 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor). ABSOLUTE HUMIDITY SENSOR CIRCUIT (1) Structure of Absolute Humidity Sensor are turned on in such a way as to change the resistance values The absolute humidity sensor includes two thermistors as in parallel with R50-1. Changing the resistance values results...
  • Page 38 R-1880LS/LST SERVICING of the touch control panel with a jumper, which brings about 1. Precautions for Handling Electronic Components an operational state that is equivalent to the oven door being This unit uses CMOS LSI in the integral part of the circuits. closed. As for the sensor-related controls of the touch control When handling these parts, the following precautions should be panel, checking them is possible if dummy resistor(s) with strictly followed. CMOS LSI have extremely high impedance resistance equal to that of the controls are used. at its input and output terminals. For this reason, it is easily (2) Servicing the touch control panel with power supply influenced by the surrounding high voltage power source, static from an external power source:...
  • Page 39 R-1880LS/LST SPECIAL SERVICING NOTE There is couple of non-replaceable parts attached to the Turn Table & Fan motor. They are called “Spark Quenchers” and are attached to prevent noise emitted by the Turn Table Motor and Fan Motor from interfer- ing with the Sensor operation. If not used on this design, it is possible (in some cases) the Sensor will “Error” immediately. (This is a non-replaceable part) There is a Spark Quencher attached to the Fan Motor as shown in (Fig. S1) (Fig. S1) There is a Spark Quencher attached to the Turn Table Motor as shown in (Fig. S2) (Fig. S2)
  • Page 40: Component Replacement And Adjustment Procedure

    R-1880LS/LST COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING AGAINST HIGH VOLTAGE: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal, electric shock. (Example) High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operat- ing the oven. 1. Disconnect the power supply cord. . Visually check the door and cavity face plate for damage (dents, cracks, signs of arcing etc.). Carry out any remedial work that is necessary before operating Do not operate the oven: the oven. 1. Without the RF gasket (Magnetron).
  • Page 41: Outer Case Removal

    R-1880LS/LST REMOVAL OF OVEN FROM WALL (Two persons recommended to remove the oven) 1. Disconnect the power supply cord, and uncoil the power supply cord. . Remove the turntable tray and support from the oven cavity. 7. Lift the oven up off the hooks at the bottom of the mounting 3. Remove the two () screws holding the oven (outer case plate. cabinet) to the top cabinet. 8. The oven is now free and can be placed on the work surface 4. Remove the two () grease filters from the base cover. selected for servicing the oven. 5. While supporting the front of the oven, unfasten the two () 9. Installation is the reverse of this procedure.
  • Page 42: Magnetron Removal

    R-1880LS/LST 10. Now, the hood fan motor is free. 18. Remove two () screws holding the AH sensor assembly to 11. Remove the hood exhaust duct from the oven cavity by the exhaust duct. lifting it up 19. Now, the AH sensor assembly and the exhaust duct are free. 1. Screw the oven lamp off from the lamp socket. 13. Remove the lamp socket from the lamp angle of the top duct Oven lamp by releasing the two () tabs of the oven lamp socket. socket 14. Pull the wire leads from the oven lamp socket by pushing the terminal hole of the oven lamp socket with the small flat type Terminal screw driver. 15. Now, the oven lamp socket is free. Wire lead 16. Release the one (1) snap band of the AH sensor assembly from the oven cavity. Terminal hole 17. Release the one (1) tab of the top duct from the AH sensor assembly. Flate type small screw driver MAGNETRON REMOVAL 1. Disconnect the power supply cord, remove the oven from wall, 6. Disconnect the filament lead of the transformer from the magnetron.
  • Page 43: Cooling Fan Motor Removal

    R-1880LS/LST COOLING FAN MOTOR REMOVAL 1. Disconnect the power supply cord, remove the oven from INSTALLATION 1. Install the fan motor to the fan duct with the two () screws. wall and remove outer case, remove the unit mounting screw . Install the fan blade to the fan motor shaft according the and hood intake duct R. (Refer to procedure of "Removal of following procedure. Oven from Wall", "Outer case Removal" and "Unit Mounting 1) Hold the center of the bracket which supports the shaft of the Screw and Hood Intake Duct R Removal".) fan motor on the flat table. . Open door and block it open.
  • Page 44: Oven Lamp Removal

    R-1880LS/LST TURNTABLE MOTOR AND COUPLING REMOVAL 1. Disconnect the power supply cord. 5. Disconnect the wire leads from the turntable motor. . Open the door and block it open. 6. Remove two () screws holding turntable motor to the oven 3. Remove the three (3) screws holding the base cover to the cavity. oven cavity 7. Now the turntable motor is free. 4. Remove the base cover from the oven cavity by pulling down 8. Pull the coupling out of the turntable motor packing which is and moving to the left slightly. installed on the oven cavity floor. 9. Now the coupling is free. STIRRER MOTOR REMOVAL 5. Disconnect the wire leads from the stirrer motor. 1. Disconnect the power supply cord and remove the oven from 6. Remove the two () screws holding the stirrer motor to the wall and remove outer case. (Refer to procedure of "Removal waveguide of the oven cavity. of Oven from Wall" and Outer case Removal") 7. Remove the stirrer motor from the waveguide.
  • Page 45 R-1880LS/LST CONTROL PANEL ASSEMBLY, CONTROL UNIT AND KEY UNIT REMOVAL 10. Remove the control panel assembly from the oven. 1. Disconnect the power supply cord. 11. Now, the control panel assembly is free. . Open the door and block it open. 1. Remove six (6) screws holding the control unit to the control 3. Remove one (1) screw holding the hood exhaust louver to panel. oven cavity front flange. 13. Now, the control unit is free. 4. Remove the hood exhaust louver from the oven by pushing 14. Remove the one (1) screw holding the key fixing plate to the the right and left tabs of the hood exhaust louver. (Refer to control panel. procedure of "HOOD EXHAUST LOUVER REMOVAL") 15. Release the four (4) tabs holding the key fixing plate to the 5. Open the oven door.
  • Page 46 R-1880LS/LST CONVECTION DUCT ASSEMBLY REMOVAL 1. Disconnect power supply cord, remove the oven from wall bent top of the heating element holder to inside using by long nose pliers as shown following and remove outer case. (Refer to procedure of "Removal of illustration. Oven from Wall" and Outer case Removal") . Open the door and block it open. 3. Discharge high voltage capacitor. Long nose plier 4. Lift the left mounting screw off the tab and slide it down from Heating the base plate left. element 5. Remove the one (1) screw holding the exhaust duct to the top duct.
  • Page 47: Door Replacement

    R-1880LS/LST DOOR SENSING SWITCH, SECONDARY, THIRD DOOR SWITCH AND MONITOR SWITCH ADJUSTMENT interrupt the circuit before the door can be opened. If the door sensing switch, secondary,primary switch and moni- 3. Monitor switch contacts close when door is opened. tor switch do not operate properly due to a misadjustment, the 4. Re-install outer case and check for microwave leakage around following adjustment should be made. door with an approved microwave survey meter. (Refer to 1. Disconnect the power supply cord and remove the oven from Microwave Measurement Procedure.) wall and remove outer case. (Refer to procedure of "Removal of Oven from Wall" and "Outer case Removal") . Open the door and block it open. 3. Discharge high voltage capacitor. 4. Loosen the two () screws holding latch hook to the oven LATCH HOOK cavity front flange.
  • Page 48: Door Disassembly

    R-1880LS/LST microwave energy from oven cavity during cook 6. Re-install the door stopper to the door assembly. cycle. This function does not require that door 7. Re-install the sash left to the oven cavity front face plate. be air-tight, moisture (condensation)-tight or 8. Re-install the hood exhaust louver to the oven cavity front face plate. light-tight. Therefore, occasional appearance of moisture, light or sensing of gentle warm air Note: After any service to the door;...
  • Page 49 R-1880LS/LST CN-D...
  • Page 50 R-1880LS/LST...
  • Page 51 R-1880LS/LST...
  • Page 52: Parts List

    R-1880LS/LST PARTS LIST REF. NO. PART NO. DESCRIPTION Q'TY CODE ELECTRIC PARTS 1- 1 FH-DZB017MRY0 High voltage rectifier assembly 1- 2 RC-QZA234WRE0 High voltage capacitor 1- 3 QFS-TA013WRE0 Temperature fuse 150 ° 1- 4 RHET-A174WRE0 Convection heater 1- 5 RMOTDA264WRZZ...
  • Page 53 R-1880LS/LST REF. NO. PART NO. DESCRIPTION Q'TY CODE OVEN PARTS 4- 1 FFTA-B004MRK0 Exhaust damper assembly 4- 2 FROLPB027MRK0 Turntable support assembly 4- 3 NTNT-A114WREZ Turntable tray 4- 4 LANGKB010MRP0 Capacitor holder 4- 5 FCOVPB002MRY0 Stirrer cover assembly 4- 6...
  • Page 54: Charcoal Filter

    R-1880LS/LST REF. NO. PART NO. DESCRIPTION Q'TY MISCELLANEOUS 6- 1 CFZK-B131MRK0 Installation material assembly 6-1-1 LBSHC0040MRE0 Grommet 6-1-2 LX-BZ0195WRE0 Toggle screw 6-1-3 XWHS750-16300 Washer 6-1-4 XBRS750P60000 Screw : 5mm x 60mm 6-1-5 XOTS740P12000 Screw : 4mm x 12mm 6-1-6 XTSS750P35000...
  • Page 55 R-1880LS/LST OVEN AND CABINET PARTS 4-52 4-52 4-50 1-17 7-25 4-50 4-51 7-24 4-16 7-24 4-33 2-10 4-39 4-22 7-11 4-36 4-25 7-24 4-37 1-21 4-24 7-11 4-40 4-46 1-13 7-17 4-38 7-11 7-20 4-44 4-20 4-54 7-21 1-16 7-14 7-15...
  • Page 56 R-1880LS/LST 4-35 MISCELLANEOUS 6-1-1 6-1-4 6-1-5 6-1-2 6-1-6 6-10 6-1-3...
  • Page 57: Packing And Accessories

    R-1880LS/LST PACKING AND ACCESSORIES DOOR PROTECTOR INSTALL MATERIAL ASSEMBLY 6-3 OPERATION MANUAL WALL TEMPLATE TOP PAD INSTALLATION INSTRUCTION WRAP COVER 6-4 TOP TEMPLATE 6-15 CHARCOAL FILTER GREASE FILTER (x 2) LOW RACK HIGH RACK BOTTOM PAD MILLER MAT 4-3 TURNTABLE TRAY...
  • Page 58 R-1880LS/LST NOTES...
  • Page 59 R-1880LS/LST NOTES...
  • Page 60 No part of this publication may be reproduced, stored in retrieval systems, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher. 2006 SHARP CORP. (5M2.00E) Printed in U.S.A...

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