SHARP R414HS Service Manual

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SUPPLEMENTAL SER VICE MANUAL

S23M204R414HE

MICROWAVE OVEN

R-414HS

MODELS

R-414HS

This is a supplemental Service Manual for Microwave Oven model R-414HS. This model is quite similar to the base models R426HS/R-426HK/R-426HW; (S13M203R426HE).

This supplemental manual must be used in conjunction with the base model service manual for complete operation, service, safety and replacement parts information.

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.

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 Rectifier Assembly, High Voltage Harness etc..)

TABLE OF CONTENTS

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO

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

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

WARNING TO SERVICE PERSONNEL .............................................................................................................. 1

MICROWAVE MEASUREMENT PROCEDURE .................................................................................................. 2

FOREWORD AND WARNING............................................................................................................................. 3

PRODUCT SPECIFICATIONS............................................................................................................................. 4

GENERAL INFORMATION ................................................................................................................................. 4

TEST PROCEDURE ..............................................................................................................................................6

TOUCH CONTROL PANEL....................................................................................................................................8

PICTORIAL DIAGRAM ........................................................................................................................................12

CPU UNIT CIRCUIT.............................................................................................................................................13

PRINTED WIRING BOARD .................................................................................................................................14

PARTS LIST........................................................................................................................................................15

PACKING AND ACCESSORIES .........................................................................................................................19

R-414HS

Page

SHARP ELECTRONCS CORPORATION

Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135

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

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R-414HS

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.

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W ARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts 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 instructions.

may result in a severe, possibly

R-414HS

Don't Touch ! Danger High Voltage

Before Servicing

1. Disconnect the power supply cord , and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

WARNING:RISK OF ELECTRIC SHOCK.

DISCHARGE THE HIGH-VOLTAGE CAPACITOR BEFORE SERVICING.

The high-voltage capacitor remains charged about 60 seconds after the oven has been switched off. Wait for 60 seconds and then short-circuit the connection of the highvoltage capacitor (that is the connecting lead of the highvoltage rectifier) against the chassis with the use of an insulated screwdriver.

Whenever troubleshooting is performed the power supply must be disconnected. It may, in some cases, be necessary to connect the power supply 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.

After repairing

1. Reconnect all leads removed from components during testing.

2. Reinstall the outer case (cabinet).

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

4. Run the oven and check all functions.

Microwave ovens should not be operated empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the oven turntable, close the door and set the power to HIGH and set the microwave timer for two (2) minutes. When the two minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out Before Servicing procedure and re- examine the connections to the component being tested.

When all service work is completed and the oven is fully assembled, the microwave power output should be checked and a microwave leakage test should be carried out.

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R-414HS

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 switch shall prevent microwave radiation emission in excess of the requirement as above mentioned. Secondary interlock relay and door sensing 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 (68OF) 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 primary interlock switch/secondary interlock relay does turn the oven OFF before any door movement.

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

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SUPPLEMENTAL SERVICE MANUAL

R-414HS

MICROWAVE OVEN

R-414HS

FOREWORD

This supplemental Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVEN; R-414HS.

The model R-414HS is quite similar to base models R-426HS/R-426HK/ R-426HW (Ref.# S13M203R426HE).

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

WARNING

Never operate the oven until the following points are ensured: (A) The door is tightly closed. (B) The door brackets and hinges are not defective. (C) The door packing is not damaged. (D) The door is not deformed or warped. (E) There is no other visible damage with the oven.

PRODUCT DESCRIPTION

GENERAL INFORMATION

TOUCH CONTROL PANEL

WIRING DIAGRAM

PARTS LIST

Servicing and repair work must be carried out only by trained service personnel.

DANGER

Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing. Service personnel - Do not contact the following parts while the appliance is energized; High Voltage Capacitor, Power Transformer, Magnetron, High 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 250V.

Removal of the outer wrap gives access to voltage above 250V. All the parts marked “∆” on parts list may cause undue microwave

exposure, by themselves, or when they are damaged, loosened or removed.

SHARP ELECTRONICS CORPORATION

SHARP PLAZA, MAHWAH,

NEW JERSEY 07430-2135

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R-414HS

SPECIFICATION

ITEM DESCRIPTION

Power Requirements 120 Volts

13.3 Amperes, 1550 watts 60 Hertz Single phase, 3 wire grounded

Power Output 1100 watts (IEC TEST METHOD)

Operating frequency of 2450MHz

Case Dimensions Width 21-11/16"

Height 12-3/8" Depth 17-3/8"

Cooking Cavity Dimensions Width 15"

Height 9-7/16"

1.4 Cubic Feet Depth 16-3/4" Control Complement Touch Control System

Clock ( 1:00 - 12:59 ) 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 .................................................................... approx. 60% of Full Power

P-50 .................................................................... approx. 50% of Full Power

P-40 .................................................................... approx. 40% of Full Power

P-30 .................................................................... approx. 30% of Full Power

P-20 .................................................................... approx. 20% of Full Power

P-10 .................................................................... approx. 10% of Full Power

P-0......................................................No power throughout the cooking time

Keep warm pad, Popcorn pads, Reheat pads, Number selection pads, Power Level pad, Timer/Clock pad, Hot Water, Cook center pads and Defrost center.

Oven Cavity Light Yes Safety Standard UL Listed FCC Authorized

DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J

GENERAL INFORMATION

GROUNDING INSTRUCTIONS

This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed and grounded in accordance with the National Electrical Code and local codes and ordinances. In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the electric current.

WARNING: Improper use of the grounding plug can result in a risk of electric shock.

Electrical Requirements The electrical requirements are a 120 volt 60 Hz, AC only, 15 or 20 amp. fused electrical supply. It is recommended that a separate circuit serving only this appliance be provided. When installing this appliance, observe all applicable codes and ordinances. A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord. Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to contact

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a qualified electrician and have it replaced with a properly grounded

3-Pronged Plug

Grounded Receptacle Box

Grounding Pin

3-Pronged Receptacle

three-pronged wall receptacle or have a grounding adapter properly grounded and polarized. If the extension cord must be used, it should be a 3-wire, 15 amp. or higher rated cord. Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentally.

CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR RE-

MOVE THE ROUND GROUNDING PRONG FROM THIS PLUG.

OVEN DIAGRAM

1. One touch door open button. Push to open door.

2. Door latches. The oven will not operate unless the door is securely closed.

3. Removable turntable support.

4. Removable turntable. The turntable will rotate clockwise or counterclockwise.

5. Oven lamp. It will light when oven is operating or door is opened.

6. Oven door with see-through window.

7. Ventilation openings. (Rear)

8. Auto-Touch control panel.

9. Time display: Digital display, 99 minutes 99 seconds.

10.Wave guide cover.

11.Power supply cord

TOUCH CONTROL PANEL

R-414HS

NOTE: The directed features are disabled after one minute when the oven is not in use. These features are automatically enabled when the door is opened and closed or the STOP/ CLEAR pad is pressed.

R-414HS

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R-414HS

TEST PROCEDURES

PROCEDURE

LETTER

I TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key Unit, and also the Control Unit is divided into two units, LSI Unit and Power Unit, and troubleshooting by unit replacement is described according to the symptoms indicated.

Before testing,

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

1. Key Unit. NOTE ;

1) Re-install the outer case (cabinet).

2) Reconnect the power supply cord after the outer case is installed.

3) Run the oven and check all functions.

The following symptoms indicate a defective key unit. a) When touching the pads, a certain pad produces no signal at all. b) When touching a number pad, two figures or more are displayed. c) When touching the pads, sometimes a pad produces no signal.

2. Control Unit The following symptoms indicate a defective control unit.

2- 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.

2- 2 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.

2- 3 Other possible problems caused by defective control unit.

a) Buzzer does not sound or continues to sound. b) Clock does not operate properly. c) Cooking is not possible.

3. If the Key unit or the Control unit is defective.

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) Replace the Control unit assembly.

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.

4. When 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 all leads removed from components during testing.

5) Re-install the outer case (cabinet).

COMPONENT TEST

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TEST PROCEDURES

R-414HS

PROCEDURE

LETTER

J KEY UNIT TEST

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. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check the

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.

COMPONENT TEST

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

7) Run the oven and check all functions.

circuit between the pins of the key unit that correspond to the STOP/CLEAR pad. When the pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the ohmmeter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and must be replaced. About the other pads, the above method may be used.

G8 G7 G6 G5 G4 G3 G2 G1

Pin NO. G1

Pin NO. G13

G10G11G12G13

POPCORN

POTATOES

RICE

ENTREES

GROUND MEAT

BAKED

BONELESS POULTRY

REHEAT

WHEN DOOR IS CLOSE

FROZEN

(DEFROST

CENTER)

STEAKS

/CHOPS

GROUND

MEAT

(COOK CENTER)

BONE-IN

POULTRY

FRESH

VEGETABLES

FROZEN

VEGETABLES

STEAKS /CHOPS

MINUTE PLUS

START

CLEAR

TIMER

CLOCK

POWER

LEVEL

STOP

CLEAR

HOT

WATER

KEEP

WARM

K RELAY TEST

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 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 the normal open terminal of the relay RY1 and the normal open terminal of the relay RY2 on the control unit with an A.C. voltmeter. The meter should indicate 120 volts, if not check oven circuit.

RY1 and RY2 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,

Key unit ribbon cable

Key unit (Membrane Switch) front view

control unit is defective.

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R-414HS

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY1 Approx. 12.0V D.C. Oven lamp / Turntable motor / Cooling fan motor RY2 Approx. 12.0V D.C. Power transformer

8. Disconnect the power supply cord, and then remove outer case.

9. Open the door and block it open.

10. Discharge high voltage capacitor.

11. Reconnect all leads removed from components during testing.

12. Re-install the outer case (cabinet).

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

14. Run the oven and check all functions.

TOUCH CONTROL P ANEL ASSEMBL Y

OUTLINE OF TOUCH CONTROL PANEL

The touch control section consists of the following units. (1) Key Unit

(2) Control Unit (The Control Unit consists of Power Unit and

LSI Unit).

The principal functions of these units and the signals communicated among them are explained below.

Key Unit

The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P20-P27. When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through P70, P71, P41, P45, P47 and AN3 to perform the function that was requested.

Control Unit

Control unit consists of LSI, reset circuit, indicator circuit, power source circuit, relay circuit, buzzer circuit, synchronizing signal circuit and back light circuit.

1) Reset Circuit

This circuit generates a signal which resets the LSI to the initial state when power is supplied.

3) Power Source Circuit

This circuit generates voltages necessary in the control unit from the AC line voltage. In addition, the synchronizing signal is available in order to compose a basic standard time in the clock circuit.

Symbol Voltage Application

VSS -5V LSI(IC1)

4) Relay Circuit

A circuit to drive the magnetron, fan motor, turntable motor and light the oven lamp.

5) Buzzer Circuit

The buzzer is responsive to signals from the LSI to emit audible sounds (key touch sound and completion sound).

6) Synchronizing Signal Circuit

The power source synchronizing signal is available in order to compose a basic standard time in the clock circuit. It accompanies a very small error because it works on commercial frequency.

7) Door Sensing Switch

A switch to “tell” the LSI if the door is open or closed.

2) Indicator Circuit

This circuit consists of 22 segments and 3 common electrodes using a Liquid Crystal Display.

8) Back Light Circuit

A circuit to drive the back light (Light emitting diodes LD1LD4).

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DESCRIPTION OF LSI

LSI

The I/O signal of the LSI is detailed in the following table.

Pin No. Signal I/O Description

R-414HS

1-2

VL2-VL1

IN Power source voltage input terminal.

Standard voltage for LCD.

3-6 AN7-AN4 IN

Terminal to change cooking input according to the Model.

By using the A/D converter contained in the LSI, DC voltage in accordance with the Model in operation is applied to set up its cooking constant.

7 AN3 IN Signal coming from touch key.

When either G13 line on key matrix is touched, a corresponding signal out of P20 - P27 will be input into AN3. When no key is touched, the signal is held at “H” level.

8 AN2 IN

To input signal which communicates the door open/close information to LSI.

Door close "H" level signal (0V). Door Open "L" level (-5V).

9 AN1 IN Terminal not used.

1 0 AN 0 I N Terminal not used.

11-13 P57-P55 OUT Terminal not used.

14 CNTR0 OUT

Signal to sound buzzer (2.0 kHz).

A: key touch sound.

0.1 sec.

B: Completion sound.

1 5 P53 OU T Terminal not used. 16 P52 OUT Oven lamp, fan motor and turntable motor driving signal

To turn on and off shut off relay (RY1). The

16.7 msec.

square waveform voltage is delivered to the RY1 driving circuit and RY2 control circuit.

2.0 sec.

During cooking

H : GN

L : -5V H : GN

L : -5V

H : GND

L : -5V

1 7 P51 OU T Terminal not used. 18 P50 OUT Magnetron high-voltage circuit driving signal.

To turn on and off the cook relay (RY2). The signals holds “L” level during microwave cook-

Maximum output

ing and “H” level while not cooking. In other cooking modes (variable cooking) the signal turns to “H” level and “L” level in repetition

70% of maximum output

according to the power level.

OFF

OFF OFF

19 P47 IN Signal similar to AN3.

When either G13 line on key matrix is touched, a corresponding signal will be input into

P46. 2 0 P46 OU T Terminal not used. 21 P45 IN Signal similar to AN3.

When either G12 line on key matrix is touched, a corresponding signal will be input into

P45.

22-23 P44-P43 OUT Terminal not used.

24 INT0 IN Signal synchronized with commercial power source frequency.

This is the basic timing for time processing of LSI.

16.7 msec.

24 sec.

8 sec.

H : GND

L : -5V H : GND

L : -5V

H : GN

L : -5V

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R-414HS

Pin No. Signal I/O Description

25 P41 IN Signal similar to AN3.

When either G11 line on key matrix is touched, a corresponding signal will be input into

P41. 2 6 P40 IN Connected to GND through the pull-down resistor. 27 RESET IN Auto clear terminal.

Signal is input to reset the LSI to the initial state when power is applied. 28 P71 IN

Signal similar to AN3.

When either G10 line on key matrix is touched, a corresponding signal will be input into

P71. 29 P70 IN

Signal similar to ANI3.

When either G9 line on key matrix is touched, a corresponding signal will be input into P70. 30 XIN IN

Internal clock oscillation frequency control input setting.

The internal clock frequency is set by inserting the ceramic filter oscillation circuit with

respect to XOUT terminal. 31 XOUT O U T Internal clock oscillation output.

Output to control oscillation input to XIN. 32 VSS IN

Power source voltage : -5.0V.

The power source voltage to the drive LSI is input to VSS terminal. 33 P27 OUT Key strobe signal.