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Sharp R-8470 Service Manual
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Sharp R-8470 Service Manual

Sharp R-8470 Service Manual

Counter top convection microwave oven
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SHARP
SERVICE MANUAL
S9610R8470Jll
COUNTER
TOP
CONVECTION
MICROWAVE
OVEN
Photo
R-8470
In the interests of user-safety
the set should
be restored to its original
condition
and only parts identical
to those specified
should
be used.
TABLE
OF CONTENTS
Page
FOREWORD
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...............................
1
CAUTION,
MICROWAVE
RADIATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PRODUCT
DESCRIPTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... 2
OPERATION
INSTRUCTIONS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
OPERATION
....................................................................................
.I.. ...............................................................
4
SERVICING
.....................................................................................................................................................
10
TOUCH
CONTORL
PANEL ASSEMBLY
.....................................................................................................
20
COMPORNENT
REPLACEMENT
AND ADJUSTMENT
PROCEDURE
...................................................
29
MICROWAVE
MEASUREMENT
PROCEDURE
..........................................................................................
34
PACKING
AND ACCESSORIES
...................................................................................................................
35
PICTORIAL
DIAGRAM
..................................................................................................................................
36
CONTROL
PANEL CIRCUIT
(R-8470)
.......................................................................................................
37
CONTROL
PANEL CIRCUIT
(R-8570)
.......................................................................................................
39
PRINTED WIRING
BOARD
..........................................................................................................................
41
PARTS LIST ....................................................................................................................................................
42
SERVICE INFORMATION
FOR CONTROL
UNIT ......................................................................................
47
SHARPCORPORATION

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Summary of Contents for Sharp R-8470

  • Page 2 R-8470 R-8570...
  • Page 3 R-8470 R-8570 Personnel with complete Operation and Service Information for the SHARP CONVECTION MICROWAVE ovens, R-8470/ entire text of this manual so they will be qualified to render satisfactory customer service. Check interlock switches and door seal carefully. Special at- tention should be given to avoid electrical shock and microwave radiation hazard.
  • Page 6 OPERATION DESCRIPTION OF OPERATING SEQUENCE feed-box, and then into the cavity where the food is placed to be cooked. during oven operation. Upon completion of the cooking time, the power transformer, oven lamp, etc. are turned off, and the OFF CONDITION generation of microwave energy is stopped.
  • Page 7 The coil of shut-off relays (RY2, RY3 and RY5) are AUTOMATIC MIX COOKING CONDITION energized, the oven lamp, cooking fan motor, Program desired cooking time and temperature by turntable motor and convection motor are turned touching the number pads and the LOW MIX/BAKE o n .
  • Page 8 The coil of shut-off relay (RY-1) is energized, the SENSOR COOKING CONDITION (R-8570 oven light and cooling fan motor are turned on, but the power transformer is not turned on. Using the SENSOR COOK function, the foods are 4. After about 16 seconds, the cook relay (RY-2) is cooked without figuring time, power level or quantity.
  • Page 9 R-8470 R-8570 0 .-...
  • Page 10 R-8470 DESCRIPTION AND FUNCTION OF COMPONENTS normally closed. At this time the upper latch switch are in the OFF condition (contacts open) due to The upper and lower latch switches are activated by their being normally open contacts switches. the latch heads on the door. When the door is opened, 2.
  • Page 11 R-8570 2. When oven is microwave cooking: Damper is in the open position. Usually, the damper is open position except during the convection cooking. 3. When oven is convection cooking: Damper position is set automatically by damper motor, 3 - l . Damper motor is energized by touching the damper switch, motor cam and damper shaft.
  • Page 12 R-8470 R-8570 SERVICING IMPORTANT: If then oven becomes inoperative be- When troubleshooting the microwave oven, it is cause of a blown monitor fuse in the monitor switch and upper latch switch forming the checks. Many of the passible causes of circuit, check the monitor switch and trouble will require that a specific test be performed.
  • Page 13 R-8470 R-8570 COOKING CONDITION Defective shut-off relay (RYZ) on relay Procedure J. Oven lamp does not light in cook unit. (Does light when door is opened) Procedure K Defective control unit Replace Burned out bulb. Check and repair wiring Open wiring of oven lamp.
  • Page 14 CONVECTION CONV indicator light but oven Defective key unit. Porcedure N does not go into a cook cycle Defective thermistor. when START pad is touched. Open wiring in circuit to above compo- Check and repair wiring. nents. Procedure I CONV indicator lights, but heating Defective heating element.
  • Page 15 R-8470 R-8570 DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO- NENTS OR WIRING. 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.
  • Page 16 3. Water container should be one (1) litre beaker made of Pyrex glass and its diameter approxi- mately 12 cm. 4. Room temperature should be around 20 “C. 5. Power supply voltage should be specification voltage. DISCHARGE THE HIGH VOLTAGE CAPACITAOR BEFORE TOUCHING ANY OVEN COMPO- NENTS OR WIRING.
  • Page 17 R-8470 LATCH MONITOR SWITCH LEVER If the monitor fuse in the primary-secondary-monitor switch circuit is blown when the door is opened, check the primary and secondary interlock switches and monitor switch according to the Test Procedure of those switches, before replacing the blown monitor fuse.
  • Page 18 R-8470 The relay unit consists of circuits including the shut-off relays, buzzer, transformer, etc. Plug power cord into wall receptacle “88888” will be flashing in the display. Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 12-pin connector (A) on the relay unit with an A.C.
  • Page 19 R-8470 R-8570 If the indicator does not respond to touching a key Pad use the following matrix and place a jumper wire between the proper pin connections with the cable connector disconnected from the control unit. If the indicator responds and oven goes into operation, the key unit was faulty.
  • Page 20 R-8470 R-8570 (6) After approximately 16 seconds, microwave energy is produced,oven should turn off when water is boiling (bubling). If the oven dose not turn off, replace the AH sensor or check the control unit, refer to expla- nation below: To determine if the sensor is defective, the simplest method is to replace it with a new re- placement sensor.
  • Page 21 R-8470 R-8570 type temperature meter must be used. A low priced bi-metal type thermometer is not reliable or accurate. The temperature should be checked approximately 5 minutes after the preheat temperature is reached (audible signal sounds four times). The temperature experienced may be approximately 20 “C more or less than indicated on the display, however, in most cases the food cooking results...

  • Page 22: Touch Control Panel Assembly

    R-8470 R-8570 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following This circuit generates voltage necessary in the units as shown in the block diagram. control unit. (1) Control Unit (2) Key Unit...
  • Page 24 R-8470 DESCRIPTION OF LSI The I/O signa I of the LSl(lX2429) is detailed in the following table. PIN NO. Refer to the touch control panel circuit about the relation between signals and digits. Normally, one pulse is output in every synchronized signal period, and input to the grid of the fluorescent display.
  • Page 25 R-8470 R-8570 PIN NO. / 15 Signal similar to E6. PIN NO. / 16 Signal similar to E6. Signal applied to touch-key section. A pulse signal is input to AN4-AN7 terminal while one of G-7 line keys on key matrix is touched.
  • Page 26 R-8470: Terminal not used. R-8570: Used for initial balancing of the bridge circuit(absolute himidity sensor). A: Key touch sound.(0.12 sec.) B: Completion sound. (2.4 sec.) C: When the temperature of the oven cavity reaches the preset temperature in the preheating mode, or when the preheating hold time (15 minutes) is elapsed.
  • Page 27 R-8470 R-8570 I I / O S I G N A L / R 5 PIN NO. To turn on and off the damper motor relay. S I G N A L j R 6 PIN NO. / 39 Signal similar to EO.
  • Page 28 R-8570 PIN NO. / 51 R-8470: Terminal not used. No connection. R-8570: Used for initial balancing of the bridge circuit (absolute humidity sensor). This input is an analog input terminal from the AH sensor circuitand connected to the A/D converter built into the I I/O PIN NO.
  • Page 29 R-8570 ABSOLUTE HUMIDITY SENSOR CIRCUIT (R-8570 16 seconds after the unit is put in the Sensor Cooking mode. The absolute humidity sensor includes two As the sensor cooking proceeds, the food is heated thermistors as shown in the illustration. One to generate moisture by which the resistance bal- thermister is housed in the closed vessel filled with ance of the bridge circuit is deviated to increase the...
  • Page 30 A -8470 SERVICING B. On some models, on the other hand, the power supply cord between the touch control panel Components and the oven proper is so long that they may This unit uses PMOS LSI in the integral part of the be separated from each other.
  • Page 32 R-8470 R-8570 MAGNETRON ASSEMBLY REMOVAL 6. Lower the magnetron assembly until the tube is clear of the waveguide. outer case. 7. Remove single (1) screw holding the cooling duct 2. Discharge the high voltage capacitor. (B) to the magnetron assembly.
  • Page 34 UPPER/LOWER LATCH SWITCHES AND MONITOR SWITCH ADJUSTMENT the upper latch hook to the oven cavity front flange If the upper and lower latch switches and monitor and adjust the upper latch hook position. switch operate properly mis-adjustment, the following adjustment should be made.

  • Page 36: Microwave Measurement

    R-8470 R-8570 MICROWAVE MEASUREMENT Recommended instruments are: After the adjustment of the door latch switches, moni- NARDA 8100 tor switch and door are completed individually or col- NARDA 8200 lectively, the following leakage test must be performed HOLDADYA HI 1500...
  • Page 37 R-8470 R-8570 TRAY PACKING FOAM N o t...
  • Page 38 a -. _ _ _ _ ~__ _ _ ___~~~---.
  • Page 39 R -8470 R-8470 R-8570 R-8570 Q30 DTA143 A TURNTABLE MOTOR OVEN LAMP FAN MOTOR A-9 A - 7 DAMPER MOTOR DTA143 A x5 130 F STOP SWITCH DAMPER SWITCH (DOOR SWITCH) Figure S-2. Contorol Panel Circuit (Mot...
  • Page 40 R-8470 R-8470 R-8570 R-8570 C C . 7 +R96 130 F OVEN I Panel Circuit (Model R-8470)
  • Page 41 R-8470 R-8570 AC240 TURNTABLE MOTOR OVEN LAMP POWER TRANSFORMER HEATING ELEMENT FAN MOT01 DAMPER MOTOF DTA143 A x! F NOT SPECIFIED, US1060 R 5 2 i.BkF STOP OVEN THERMISTOR...
  • Page 42 R-8470 R -8570 12 ' H I G H MEDHIGH START HOLD DEFROST (KEY UNIT...
  • Page 43 R-8470 R -8570...

  • Page 44: Parts List

    C P W B F 2 1 4 S W R K 0 Control unit: R-8570 3-pin connector (F),(H): R-8570 Q C N C M A 0 4 7 D R E O 2-pin connector (H): R-8470 R V - KXA002DREO Fluorescent display tube R C - EZA059DREO...
  • Page 45 R H - DZA002DREO Diode (US1 060): R-8570 D52, Diode (11 ES1 ): R-8470 R H - D Z A O l 1 D R E O R H - D Z A O l 1 D R E O...

  • Page 46: Oven Parts

    Lower latch hook 4-l 8 Stop switch lever 4-l 9 P D U C - 0466WRWO Steam duct (left): R-8470 P D U C - 0508WRWO Steam duct (left): R-8570 4 - 2 0 P D U C - AO93WRWO...
  • Page 47 4 - 5 3 Heating element insulator 4 - 5 4 Turntable roller assembly 4 - 5 5 Door assembly, complete: R-8470 Door assembly, complete: R-8570 Latch plate Joint lever Upper latch head L S T P P A O l 8WRFO...
  • Page 48 R-8470 R-8570 Note : The voltage supplied to the parts marked “*” is greater than 250V. : Refer to “REPLACEMENT PARTS LIST” described at after page. Screw ; outer case cabinet mtg L X - EZOO46WREO Screw ; fuse holder mtg Screw ;...
  • Page 49 R-8570 USED PART NO. REF. NO. LISTED PART NO. USED PART NO. L I S T E D P A R T N O . REF. NO. R C - EZTIOGAFI R C - EZA059DREO R C - EZT475AFl R DZl 5 1 P D R E O ‘, S D - ST2HAl 5 1 R C - EZAO61 D R E O C5 etc...
  • Page 50 R-8470 R-8570...
  • Page 51 R-8470 R-8570...
  • Page 52 R-8470 R-8570...
  • Page 53 R-8470 R-8570 DOOR ASSEMBLY MISCELLANEOUS Trans.
  • Page 54 If you fix them s shown in Figure 2, the mains supply cord will not be secured firmly. Therefore, make sure to fix them as shown in figure 1. SUPPLY Figure 1. Correct Fixing ‘86 0 SHARP CORP. (9N0.75E) Printed in Japan...

This manual is also suitable for:

R-8570