CHAPTER 12. CIRCUIT DIAGRAMS CHAPTER 6. FUNCTION OF IMPORTANT COMPO- NENTS Parts List CHAPTER 7. TROUBLESHOOTING GUIDE This document has been published to be used SHARP CORPORATION for after sales service only. The contents are subject to change without notice.
CONTENTS CHAPTER 1. BEFORE SERVICING Procedure G: TEMPERATURE FUSE GENERAL IMPORTANT INFORMATION ..1-1 AND TERMAL CUT-OUT TEST ....8-3 CAUTION MICROWAVE RADIATION ..1-1 Procedure H: CONVECTION HEATER WARNING ..........1-1 TEST............8-3 Procedure I: THERMISTOR TEST ..... 8-3 CHAPTER 2.
 GENERAL IMPORTANT INFORMATION This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information. It is recommended that service engineers carefully study the entire text of this manual, so they will be qualified to render satisfactory customer ser- vice.
When the two minutes has elapsed (timer at zero) carefully check that Sharp recommend that wherever possible fault-finding is carried out the water is now hot. If the water remains cold carry out 3D checks and with the supply disconnected. It may, in some cases, be necessary to reexamine the connections to the component being tested.
R990K(W) CHAPTER 3. R990K(W) PRODUCT SPECIFICATIONS Service Manual DESCRIPTION 230 - 240 Volts Power Requirements 50 Hertz Single phase, 3 wire earthed 1600 W (Microwave) Power Consumption 1600 W (Convection) 900 watts (IE60705C) Power Output Operating frequency 2450 MHz Width 627 mm Case Dimensions Height 378 mm Depth 487 mm...
R990K(W) CHAPTER 4. R990K(W) APPEARANCE VIEW Service Manual  OVEN 1. Ventilation opening 2. Oven lamp 3. Door hinges 4. Door safety latches 5. See through door 6. Door seal and sealing surfaces 7. Door open button 8. Touch control panel 9.
Figure O-1 on page 12-1 1. The display flashes “SHARP”, “MICRO-”, “WAVE”,'OVEN”. 2. MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW COOKING To set any programmes or set the clock, you must first touch the STOP/CLEAR pad.
R990K(W) 2) The oven will continue to function for 30 minutes, turning the convection heater on and off, as needed to maintain the 8 S E C . 40 S E C . selected preheat temperature. The oven will shut-down com- pletely after 30 minutes.
R990K(W)  FIRE SENSING FEATURE (MICROWAVE MODE) AH S E NS OR This model incorporates a sensing feature which will stop the oven's operation if there is a fire in the oven cavity during microwave cooking. This accomplished by the LSI repeatedly measures the voltage across the temperature measurement circuit (thermistor) during it's 32-sec- onds time base comparing the obtained voltage measurements.
R990K(W) CHAPTER 6. R990K(W) FUNCTION OF IMPORTANT COMPONENTS Service Manual  DOOR OPEN MECHANISM  THERMAL CUT-OUT 150C (CONV.) The door is opened by pushing the open button on the control panel, The oven thermal cut-out located on the left side of the thermal protec- refer to the Figure D-1.When the open button is pushed, the open tion plate is designed to prevent damage to the convection heater unit lever pushes up the switch lever, and then the switch lever pushes up...
R990K(W)  CONVECTION COOKING SYSTEM 1) Damper motor is energized by touching the convection, temper- ature and START pads. This oven is designed with a hot air heating system where food is not 2) When damper is in the closed position (dampers witch is OFF), directly heated by the convection heater, but is heated by forced circu- its signal is sensed by the control unit, and shut-off relay (RY4) lation of the hot air produced by the convection heater.
R990K(W) CHAPTER 7. R990K(W) TROUBLESHOOTING GUIDE Service Manual  FOREWORD When troubleshooting the microwave oven, it is helpful to follow the IMPORTANT: Sequence of Operation in performing the checks. Many of the possible If the oven becomes inoperative because of a blown fuse F10A in the causes of trouble will require that a specific test be performed.
R990K(W) CHAPTER 8. R990K(W) TEST PROCEDURES Service Manual  Procedure A: MAGNETRON (MG) TEST NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION. CARRY OUT 3D CHECKS. Isolate the magnetron from the high voltage circuit by removing all leads connected to the filament terminal. To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron filament terminals, the meter should show a reading of less than 1 ohm.
R990K(W) 1000g 1000g 1000g T1 C T2 C Heat up for 50 sec.  Procedure B: POWER TRANSFORMER TEST WARNING: High voltages and large currents are present at the secondary winding and filament winding of the power transformer. It is very dangerous to work near this part when the oven is on.
R990K(W)  Procedure E: SWITCH TEST CARRY OUT 3D CHECKS. Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the following table. Table: Terminal Connection of Switch Plunger Operation Common terminal to Normally open terminal Common terminal to Normally close terminal Released Open circuit...
R990K(W) Room Temp....20°C - 30°C Resistance.....Approx. 350kΩ - 155kΩ If the meter does not indicate above resistance, replace the thermistor. CARRY OUT 4R CHECKS.  Procedure J: MOTOR WINDING TEST CARRY OUT 3D CHECKS. Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two terminals as described in the table below. Table: Resistance of Motor Motors Resistance...
R990K(W) c) Only one indicator does not light up. 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.
R990K(W) Power transformer or secondary circuit defective. The rated voltage is applied to primary side of power transformer. Check and repair. Only pattern at “a” is broken. *Insert jumper wire J1 and solder. Pattern at “a” and “b” are broken. *Insert the coil RCILF2003YAZZ between “c”...
R990K(W) f) The display will start to count down the remaining cooking time, and the oven will turn off automatically after the water is boiling (babbling). If new sensor dose not operate properly, the problem is with the control unit. 2.
R990K(W) CHAPTER 9. R990K(W) TOUCH CONTROL PANEL ASSEMBLY Service Manual  OUTLINE OF TOUCH CONTROL PANEL 4) ACL Circuit A circuit to generate a signals which resetting the LSI to the initial The touch control section consists of the following units as shown in state when power is applied.
R990K(W) Pin No. Signal Description Digit selection signal. The relationship between digit signal and digit are as fol- ß(50Hz) lows; Digit signal Digit G ND P02......2nd. P03......1st. P 03 P01......3rd. P 02 P00......4th. P37......5th. P 01 P36......6th. P 00 P35......
R990K(W) Pin No. Signal Description Signal to synchronize LSI with commercial power source freqency. This is the basic timing for all real time processing of LSI. H : GND INT1 L (-5V) 20 msec. Connected to GND. Auto clear terminal. Signal is input to reset the LSI to the initial state when power is applied.
R990K(W) Pin No. Signal Description Segment data signal. Signal similar to P23. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to P24-P27 terminal while one of G-6 line keys on key matrix is touched. Segment data signal. Signal similar to P23.
R990K(W)  SERVICING FOR TOUCH CONTROL PANEL 1. Precautions for Handling Electronic Components 2. Servicing the touch control panel with power supply from an exter- nal power source: This unit uses CMOS LSI in the integral part of the circuits. When han- Disconnect the touch control panel completely from the oven dling these parts, the following precautions should be strictly followed.
R990K(W)  PRECAUTIONS FOR USING LEAD-FREE SOLDER 1. Employing lead-free solder The “Main PWB” of this model employs lead-free solder. This is indicated by the “LF” symbol printed on the PWB and in the service manual. The suffix letter indicates the alloy type of the solder. Example: Indicates lead-free solder of tin, silver and copper 2.
Please refer to ”OVEN PARTS, CABINET PARTS, DOOR PARTS”, when carrying out any of the following removal procedures: WARNING FOR WIRING To prevent an electric shock, take the following precautions. 3) Sharp edge: 1. Before wiring, Bottom plate, Oven cavity, Weveguide flange, Chassis support and other metallic plate.
R990K(W)  POWER TRANSFORMER REMOVAL 1. REMOVAL 2. Insert the two edges of the transformer into two metal tabs of the base cabinet. 1. CARRY OUT 3D CHECKS. 3. Make sure the transformer is mounted correctly to the corners 2. Disconnect the wire leads from power transformer. underneath those tabs.
R990K(W) 2. HEATING ELEMENT AND THERMISTOR 3. Heating element is free. 4. Remove two (2) screws holding thermistor to heater duct. 1. Remove two (2) screws holding heating element to heater duct. 5. Thermistor is free. 2. Loosen two (2) screws holding holders to heater duct and take heating element out of heating element holders.
R990K(W) CAUTION: 2) Apply the screw lock tight into the hole (for shaft) of the fan blade. • Do not use this removed fan blade again. Because the hole (for shaft) of it may become bigger than a standard 3) Install the fan blade assembly to the shaft of fan motor by push- one.
R990K(W)  STOP SWITCH, UPPER LATCH SWITCH, LOWER LATCH SWITCH AND MONITOR SWITCH REMOVAL 1. REMOVAL 2. REINSTALL 1. CARRY OUT 3D CHECKS. 1. Re-install latch lever and each switch in its place, refer to Figure C- 2. Remove control panel assembly, refer to “Control Panel Removal”. 2.
R990K(W) 1. Door latch heads smoothly catch the latch hook through the latch holes, and the latch head goes through the center of the latch hole. 2. Deviation of the door alignment from horizontal line of cavity face UP P E R OV E N HING E plate is to be less than 1.0mm.
R990K(W) CHAPTER 11. R990K(W) MICROWAVE MEASUREMENT Service Manual After adjustment of door latch switches, monitor switch and door are completed individually or collectively, the following leakage test must be per- formed with a survey instrument and it must be confirmed that the result meets the requirements of the performance standard for microwave oven. REQUIREMENT The safety switch must prevent microwave radiation emission in excess of 5mW/cm at any point 5cm or more from external surface of the oven.
BOTTOM PAD ASSEMBLY FPADBA363WRK0 TRAY PACKING FOAM PACKING CASE SPADPA198WRE0 SPAKCE322WREZ [R-990K(S)] SPAKCE323WREZ [R-990K(W)] Not replaceable items. This document has been published to be used SHARP CORPORATION for after sales service only. The contents are subject to change without notice.
R990K(W) PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK  OVEN PARTS ELECTRICAL PARTS FH-DZA053WRK0 High voltage rectifier assembly FH-HZA041WRE0 Thermistor assembly QACC-A141WRZZ Power supply cord QACC-A155WRZZ Power supply cord (Interchnageable) (for production use) QFS-CA026WRZZ Fuse F10A QFS-TA013WRE0 Temperature fuse 150C (Magnetron) RTHM-A080WRE0 Thermal cut-out 145C (Magnetron) (Interchangeable) RTHM-A112WRE0...
R990K(W) PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK  OVEN PARTS 4-14 PCUSUA167WRP0 Cushion 4-15 PCUSUA424WRP0 Cushion 4-16 FDUC-A322WRW0 Steam duct assembly 4-17 MCAMPA030WRF0 Damper cam 4-18 NSFTTA114WRE0 Damper shaft 4-19 FFTA-A034WRK0 Damper door assly 4-20 PDUC-A269WRW0 Damper duct 4-21 PCUSGA410WRP0 Cushion...
R990K(W)  DOOR AND CONTROL PANEL PARTS 3-1E 6-10 3-1F 7-18 3-2-4 7-18 3-2-6 3-2-1 3-2-5 3-2-3 3-2-2 5-15 3-2-7 5-12 5-13 5-11 5-12 5-11 5-11 5-10 5-11 5-14 Actual wire harness may be different than illustration.
R990K(W) PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK  DOOR AND CONTROL PANEL PARTS CONTROL PANEL PARTS DPWBFB724WRU0 Control unit (New Zealand only) 3-1E RV-KXA077DRE0 Fluorescent display tube 3-1F PCUSGA381WRP0 Cushion DPNLCB960WRKZ Control panel frame with key unit [R-990K(W)] DPNLCB958WRKZ Control panel frame with key unit [R-990K(S)] 3-2-1...
R990K(W) PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK  OTHER VCEAB31VW106M Capacitor 10uF 35V VCEAB31HW104M Capacitor 0.1uF 50V RC-KZA087DRE0 Capacitor 0.1uF 50V VCKYD11CY103N Capacitor 0.01uF 16V VCKYD11CY103N Capacitor 0.01uF 16V VCKYD11CY103N Capacitor 0.01uF 16V RMPTEA009DRE0 Capacitor array 330pF x 4 RCRS-A035DRE0 Ceramic resonator (CST4.19MGW) D1-4...
R990K(W) INDEX PRICE PART PRICE PART PARTS CODE PARTS CODE RANK MARK RANK RANK MARK RANK 1-4-22 NCPL-A021WRF0 [ C ] 1-4-32 CDORFB034WRKZ NFANJA020WRE0 NFANMA019WRW0 1-4-9 CDORFB035WRKZ NPLYBA025WRF0 1-4-10 [ D ] 2-3-5 NSFTTA042WRE0 2-5-1 DDORFA820WRY0 1-4-18 NSFTTA114WRE0 DPNLCB958WRKZ 2-3-2 1-4-3 NTNT-A019WRH0 DPNLCB960WRKZ...
R990K(W) PRICE PART PRICE PART PARTS CODE PARTS CODE RANK MARK RANK RANK MARK RANK 1-1-19 RTHM-A099WRE0 [ X ] 1-1-20 RTHM-A111WRE0 1-7-9 XBPS730P14K00 1-1-5 RTHM-A112WRE0 XBPS740P06KS0 1-7-14 RTHM-A117WRE0 1-1-20 XBPS740P25000 1-7-10 RTHM-A120WRE0 1-1-5 1-7-11 XBTWW40P06000 1-1-19 RTHM-A121WRE0 1-7-21 XCBWW30P06000 1-1-21 RTRN-A545WRE0 1-7-17...