Sharp R-2397 User Manual

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SER VICE MANU AL

S5708R2397H/X

COMMERCIAL

MICROWAVE OVEN

R-2397

MODEL

R-2397

In interests of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used.

TABLE OF CONTENTS

Page

CAUTION, MICROWAVE RADIATION ...................................................................................................... 1

WARNING................................................................................................................................................... 1

PRODUCT SPECIFICATIONS................................................................................................................... 2

GENERAL IMPORTANT INFORMATION ................................................................................................... 2

APPEARANCE VIEW................................................................................................................................. 3

OPERATION SEQUENCE ......................................................................................................................... 4

FUNCTION OF IMPORTANT COMPONENTS .......................................................................................... 5

SERVICING ............................................................................................................................................... 7

TEST PROCEDURE ................................................................................................................................ 10

TOUCH CONTROL PANEL ASSEMBLY .................................................................................................. 17

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE..................................................... 24

MICROWAVE MEASUREMENT .............................................................................................................. 29

WIRING DIAGRAM .................................................................................................................................. 30

PICTORIAL DIAGRAM............................................................................................................................. 31

CONTROL PANEL CIRCUIT .................................................................................................................... 32

PRINTED WIRING BOARD ...................................................................................................................... 33

PARTS LIST............................................................................................................................................. 34

SHARP CORPORATION

R-2397

SERVICE MANUAL

COMMERCIAL

R-2397

GENERAL IMPORTANT INFORMATION

R-2397

PRODUCT SPECIFICATIONS

GENERAL 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 service.

CAUTION

MICROWAVE RADIATION

DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.

Service engineers should not be exposed to the microwave energy which may radiate from the magnetron or other microwave generating devices if it is improperly used or connected. All input and output microwave connections, waveguides, flanges and gaskets must be secured. Never operate the device without a microwave energy absorbing load attached. Never look into an open waveguide or antenna while the device is energized.

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 not any other visible damage with the oven.

APPEARANCE VIEW

OPERATING SEQUENCE

FUNCTION OF IMPORTANT COMPONENTS

SERVICING AND TROUBLESHOOTING CHART

TEST PROCEDURE

TOUCH CONTROL PANEL ASSEMBLY

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

MICROWAVE MEASUREMENT

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

All the parts marked "*" on parts list are used at voltages more than 250V.

Removal of the outer wrap gives access to potentials 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 CORPORATION

OSAKA, JAPAN

WIRING DIAGRAM

PARTS LIST

R-2397

PRODUCT DESCRIPTION

SPECIFICATION

ITEM DESCRIPTION

Power Requirements 230 Volts

50 Hertz

Single phase, 3 wire grounded Power Consumption 2.7 kW Approx. 13A Power Output 1700 watts nominal of RF microwave energy (Method of IEC 705)

Operating frequency of 2450MHz Outside Dimensions Width 510mm

Height 335 mm

Depth 470 mm Cooking Cavity Dimensions Width 330 mm

Height 180 mm

Depth 330 mm Control Complement Touch Control System

The combination of cooking time and microwave power

The oven can be programmed a series of up to 3 cookling stages.

The combination of microwave power and cooking time that can be input as

folllows.

Cooking Micrwave power level Sequence that can be used. Cooking time that can be iused.

1 Stage only 0-100% Max. 30 minutes

2 or 3 Stage

NOTE:If the oven used with the power level above 40% on any stage, the

maximum cooking time is 30 minutes in total.

Microwave Power level

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

MANUAL / REPEAT key, NUMBER keys

MICROWAVE POWER SETTING key

STOP / CLEAR key, START Key

DOUBLE QUANTITY key, DEFROST key

SET key, CHECK key, VOLUME key Set Weight Approx. 33kg

0-40% all stages Max. 30 minutes any stages

Max. 60 minutes for 2 stages Max. 90 minutes for 3 stages

50-100% Max. 30 minutes for 3 stages

GENERAL INFORMATION

WARNING

THIS APPLIANCE MUST BE EARTHED

IMPORTANT

THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:

GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE

OVEN

2345

1011

1. Control panel

2. Hole for safety door latches

3. Ceramic floor

4. Splash cover

5. Oven light

6. Air intake filter

7. Air intake openings

8. Oven cavity

9. Door seals and sealing surfaces

10. Door hinges

11. Oven door with see-through window

12. Door safety latches

13. Door handle.

14. Outer cabinet

15. Removable cover over oven light bulb

16. Air vent openings

17. Power supply cord 18 Mounting plate 19 Screw for mounting plate

APPEARANCE VIEW

AUTO TOUCH CONTROL PANEL

DEF

DOUBLE

FILTER

CHECK

POWER

1 2 3 4 5 6 7 8 9 0

15 17

NUMBER

1 2 3

5 7 8 9

16 18

R-2397

DISPLAY AND INDICATORS

Check indicators after the oven starts to confirm the oven is operating as desired.

1. Heating indicator This indicator shows cooking in progress.

2. Memory number indicator

3. Defrost indicator

4. Check mode indicator

5. Power level display

6. Time display

7. Filter indicator

8. Double quantity mode indicator

9. 3rd. stage indicator

10. 2nd. stage indicator

11. 1st. stage indicator

OPERATING KEYS

12. DOUBLE QUANTITY key

13. DEFROST key

14. NUMBER keys

15. MANUAL/ REPEAT key

16. STOP/CLEAR key

17. MICROWAVE POWER SETTING key

18. START key

19. SET key

20. VOLUME key

21. CHECK key

INSTALLATION INFORMATION

When this commercial microwave oven is installed near other commercial electrical appliances, connect a lead wire to each equivalent potential terminal with equipotential marking between them (insert a lead wire between a washer and an earth angle, and screw them), as shown in Fig. A-1, to make sure that they are at equivalent potential. If any lead wire is not connected between them, when person touch them he/she will get a electric shock.

COMMERCIAL MICROWAVE OVEN OTHER COMMERCIAL 

Equipotential marking

Lead wire

Screw

Washer

Earth angle (Equivalent potential terminal)

Lead wire

Figure A-1

ELECTRICAL APPLIANCE

Equivalent  potential terminal

R-2397

OPERATION SEQUENCE

OFF CONDITION

Closing the door activates all door interlock switches (1st latch switch, 2nd latch switch, 3rd latch switch and stop switch)

IMPORTANT

When the oven door is closed, the monitor switch contacts COM-NC must be open. When the microwave oven is plugged in a wall outlet (230 volts, 50Hz), the line voltage is supplied to the point

A5+A7 in the control panel.

Figure O-1 on page 30

1. The digital display shows . NOTE: When the door is opened or after cooking, oven

lamp, blower motor and stirrer motors work for 1 minute.

MICROWAVE COOKING CONDITION

Touch MANUAL/ REPEAT key and enter a desired cooking time with the touching NUMBER key. And then touch START key.

Function sequence Figure O-2 on page 30

CONNECTED COMPONENTS RELAY Oven lamp/ Blower motor/ Stirrer motors RY1 Power transformer (rear) RY3 Power transformer (front) RY4

1. The line voltage is supplied to the primary winding of the high voltage transformer. The voltage is converted to about 3.3 volts A.C. output on the filament winding and high voltage of approximately 2000 volts A.C. on the secondary winding.

2. The filament winding voltage (3.3 volts) heats the magnetron filament and the high voltage (2000 volts) is sent to the voltage doubling circuit, where it is doubled to negative voltage of approximately 4000 volts D.C..

3. The 2450 MHz microwave energy produced in the magnetron generates a wave length of 12.24 cm. This energy is channelled through the waveguide (transport channel) into the oven cavity, where the food is placed to be cooked.

4. When the cooking time is up, a signal tone is heard and the relays circuits to the high voltage transformers. The relay remains and oven lamp, blower motor and stirrer motors work for 1 minute.

5. When the door is opened during a cook cycle, the switches come to the following condition.

SWITCH CONTACT COOKING 1st latch switch COM-NO Closed Open Monitor switch COM-NC Open Closed 2nd latch switch COM-NO Closed Open Stop switch COM-NO Closed Open 3rd latch switch COM-NO Closed Open

The circuits to the high voltage transformers are cut off when the 1st latch, 2nd latch, 3rd latch and stop switches are made open. The blower motor, stirrer motors and oven lamp remains on even if the oven door is opened after the cooking cycle has been interrupted, because

RY3+RY4 go back to their home position. The

RY1

CONDITION DURING DOOR OPEN

(NO COOKING)

the relay RY1 stays closed. Shown in the display is the remaining time, but the program is cancelled if the oven is not started within 3 minutes.

6. MONITOR SWITCH CIRCUIT The monitor switch is mechanically controlled by oven door, and monitors the operation of the 1st latch switch.

6-1. When the oven door is opened during or after the cycle

of a cooking program, the 1st, 2nd, 3rd latch and stop switches must open their contacts first. After that the contacts

(COM-NC) of the monitor switch can be

closed.

6-2. When the oven door is closed, the contacts

(COM-NC) of the monitor switch must be opened first. After that the contacts

(COM-NO) of the 1st, 2nd, 3rd latch and

stop switches must be closed.

6-3. When the oven door is opened and the contacts of the

1st latch switch remain closed, remains closed, the fuse F6.3A will blow, because the monitor switch is closed and a short circuit is caused.

MICROWAVE VARIABLE COOKING

When the microwave oven is preset for variable cooking power, the line voltage is supplied to the high voltage transformers intermittently within a 48 second time base through the contacts of the relays RY3+RY4. The following levels of microwaves power are given.

48 sec. ON

Number key

44sec. ON

Number key 9

40 sec. ON

Number key 8

36 sec. ON

Number key 7

32 sec. ON

Number key 6

26 sec. ON

Number key 5

22 sec. ON

Number key 4

16 sec. ON

Number key 3

12 sec. ON

Number key 2

8 sec. ON

Number key 1

0 sec. ON

Number key 0

NOTE: The ON/OFF time ratio does not exactly corre-

spond to the percentage of microwave power, because approx. 3 seconds are needed for heating up the magnetron filament.

TWO MAGNETRON OPERATION SYSTEM

Two magnetrons MG1+MG2 are equipped in order to get higher microwave power output. The primary windings of the high voltage transformers magnetron can be oscillated alternatively according to the frequency of the power supply. Refer to the Figure 1 and 2.

T1+T2 are connected so that each

R-2397

COMMERCIAL FREQUENCY (50HZ)

POWER OUTPUT BY MAGNETRON 1

POWER OUTPUT BY MAGNETRON 2

OPERATION OF MAGNETRON

T1: HIGH VOLTAGE TRANSFORMER

(REAR)

C1: H.V. CAPACITOR

ASYMMETRIC

RECTIFIER

H. V. RECTIFIER

MG2: MAGNETRON (LOWER)

T2: HIGH VOLTAGE TRANSFORMER

(FRONT)

C2: H.V. CAPACITOR

ASYMMETRIC

RECTIFIER

H. V. RECTIFIER

MG1: MAGNETRON (UPPER)

Figure B-1. High Voltage Circuit

FUNCTION OF IMPORTANT COMPONENTS

DOOR OPEN MECHANISM

1. The door release lever is pulled.

2. The upper latch head is lifted up by the linked door release lever.

3. The latch lever is lifted up by the door release lever.

4. The joint lever is lifted up by the latch lever.

5. The lower latch head is lifted up by the joint lever.

6. Now both latch heads are lifted up, so they can be released from the latch hook.

7. Now the door can be opened.

Door release lever

Joint lever

Latch head

Figure D-1. Door Open Mechanism

Latch head

Monitor switch

Latch hook

2nd. latch switch 1st. latch switch

Stop switch

3rd. latch switch

Figure B-2. Operation of Magnetron

MONITOR SWITCH

The monitor switch is activated (the contacts opened) the upper latch head and switch lever A while the door is closed. The switch is intended to render the oven inoperative by means of blowing the fuse F6.3A when the contacts of the 1st latch switch fail to open when the door is opened.

Function

1. When the door is opened, the monitor switch contacts close (to the ON condition) due to their being normally closed. At this time the 1st latch switch is in the OFF condition (contacts open) due to their being normally open contact switches.

2. As the door goes to a closed position, the monitor switch contacts are opened and 1st latch switch contacts are closed (On opening the door, each of these switches operate inversely.)

3. If the door is opened and the 1st latch switch contacts fail to open, the fuse F6.3A blows simultaneously with closing of the monitor switch contacts.

CAUTION:BEFORE REPLACING A BLOWN FUSE

F6.3A TEST THE 1ST LATCH SWITCH, MONITOR SWITCH AND MONITOR RESISTOR FOR PROPER OPERATION. (REFER TO CHAPTER “TEST PROCEDURE”).

MONITOR RESISTOR

The monitor resistor prevents the fuse F6.3A 250V bursting when the fuse F6.3A 250V blows due to the operation of the monitor switch.

1ST LATCH SWITCH, 2ND LATCH SWITCH, 3RD LATCH SWITCH AND STOP SWITCH

1. When the oven door is closed, the contacts COM-NO must be closed.

2. When the oven door is opened, the contacts COM-NO must be opened.

NOISE FILTER

The noise filter assembly prevents radio frequency interference that might flow back in the power circuit.

WEAK POINT

If the wire harness or electrical components make a shortcircuit, this weak point blows to prevent an electric shock or fire hazard.

R-2397

FUSE F6.3A 250V

1. If the wire harness or electrical components are shortcircuited, this fuse blows to prevent an electric shock or fire hazard.

2. The fuse also blows when 1st latch switch remains closed with the oven door open and when the monitor switch closes.

ASYMMETRIC RECTIFIER

The asymmetric rectifier is solid state device that prevents current flow is both directions. And it prevents the temperature rise of the high voltage transformer by blowing the weak point when the high voltage rectifier is shorted.

D2 D1

ASYMMETRIC RECTIFIER

HIGH VOLTAGE RECTIFIER

The rated peak reverse voltage of D1 of the asymmetric rectifier is 6 KV The rated peak reverse voltage of D2 of the asymmetric rectifier is 1.7 KV. D1 and D2 of the asymmetric rectifier or high voltage rectifier are shorted when the each peak reverse voltage goes beyond the each rated peak reverse voltage.

1. The high voltage rectifier is shorted by some fault when microwave cooking.

2. The peak reverse voltage of D2 of the rectifier goes beyond the rated peak reverse voltage 1.7 KV in the voltage doubler circuit.

3. D2 of the rectifier is shorted.

4. The large electric currents flow through the high voltage winding of the high voltage transformer.

5. The large electric currents flow through the primary winding of the high voltage transformer.

6. The weak point blows by the large electric currents.

7. The power supplying to the high voltage transformer is cut off.

EXHAUST THERMISTOR

The thermistor is a negative temperature coefficient type. The temperature in the exhaust duct is detected through the resistance of the thermistor. If the temperature is high, the control panel will display “EE7” and the oven will stop to avoid overheating and catching fire. If the thermistor is open, the control panel will display "EE6" and the oven will stop.

MAGNETRON THERMISTOR

The air temperature around the lower magnetron is detected through the resistance of the thermistor. If the temperature is high, the control panel will display "EE17" and the oven will stop to protect the lower magnetron against overheat. If the thermistor is open, the control panel will display "EE16" and the oven will stop.

MAGNETRON THERMAL CUT-OUTS 145˚

These thermal cut-outs protect the magnetrons against overheat. If their temperature go up higher than 145˚C because the blower motor is interrupted, the ventilation openings are blocked, the thermal cut-outs will open and the line voltage to the high voltage transformer will be cut off and the operations of the magnetrons will be stopped. The defective thermal cut-out must be replaced with new rated one.

BLOWER MOTOR THERMAL CUT-OUT 115˚C

This thermal cut-out protect the blower motor against overheat. If its temperature goes up higher than 115˚C because the blower motor is locked or the ventilation openings are blocked, the contacts of the thermal cut-out will open and the line voltage to the control unit will be cut off and the operation of the oven will be stopped. The defective thermal cut-out must be replaced with new rated one.

OVEN THERMAL CUT-OUT 115˚C

This thermal cut-out protects the oven against overheat. If the temperature goes up higher than 115˚C because the food catches fire, the contacts of and the line voltage to the control unit will be cut off and the operation of the oven will be stopped. The defective

thermal cut-out will open

thermal

cut-out must be replaced with a new rated one.

BLOWER MOTOR

The blower motor drives a blade which draws external cool air. This cool air is directed through the air vanes surrounding the magnetrons and cools the magnetrons. This air is channelled through the oven cavity to remove steam and vapours given off from the heating foods. It is then exhausted through the exhausting air vents at the oven cavity.

STIRRER MOTOR

The stirrer motor drives a stirrer antenna to stir the microwave radiation from the waveguide.

INTAKE THERMISTOR

This thermistor detects ambient air temperature.

R-2397

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts will result in electrocution. High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier assembly, High voltage harness.

REMEMBER TO CHECK 3D

1) Disconnect the supply.

2) Door opened, and wedged open.

3) Discharge high voltage capacitor. WARNING AGAINST THE CHARGE OF THE

HIGH-VOLTAGE CAPACITOR

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

Sharp recommend that wherever possible fault-finding is carried out with the supply disconnected. It may in, some cases, be necessary to connect the supply after the outer case has been removed, in this event carry out 3D checks and then disconnect the leads to the primary of the high voltage transformer. Ensure that these leads remain isolated from other components and the oven chassis. (Use insulation tape if necessary.) When the testing is completed carry out 3D checks and reconnect the leads to the primary of the high voltage transformer.

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

REMEMBER TO CHECK 4R

1) Reconnect all leads removed from components during testing.

2) Replace the outer case (cabinet).

3) Reconnect the supply.

4) Run the oven. Check all functions.

Microwave ovens should not be run empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the oven tray, close the door and press Manual / Repeat key and set the microwave time for one (1) minute. Set the power level to 100% and push the START button. When the one minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out 3D checks and reexamine the connections to the component being tested.

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.

IMPORTANT: If the oven becomes inoperative because

of a blown fuse F2 F6.3A in the 1st latch switch - monitor switch - monitor resisitor circuit, check the 1st latch switch, monitor switch and monitor resistor before replacing the fuse F6.3A.

R-2397

CONDITION

OFF CONDITION

ON CONDITION

TEST PROCEDURE

POSSIBLE CAUSE

AND

DEFECTIVE PARTS

PPROBLEM

“ . “ does not appear on display when power cord is plugged into wall outlet.

Control panel can not accept key in. Fuse F6.3A blows when the door is opened. Home fuse blowns when power cord is plugged

into wall outlet. Weak point A017 blowns when power cord is

plugged into wall outlet. Oven lamp, fan motor and stirrer motors do not

work for 1 minute whenever the door is opened or after cooking.

Fuse F2 F6.3A blowns when power cord is plugged into wall outlet.

Oven lamp does not light when door is opened. (Blower and stirrer motors work)

Blower motor does not work when door is opened. (Oven lamp lights and stirrer motors work)

“EE 1” appear in display. “EE 2” appear in display. “EE 3” appear in display . “EE 6” appear in display. “EE 7” appear in display. “EE 9” appear in display. Oven lamp, blower motor and stirrer motors do

not work. Oven lamp does not work. Blower motor does not work. Oven does not stop after end of cooking cycle or

when STOP/CLEAR key is touched. (Oven lamp, blower motor and stirrer motors stop.)

Home fuse blows when starting the oven. Oven goes into cook cycle but shuts down

before end of cooking cycle. Oven seems to be operating but no heat is

produced in oven load. It passed more than 1 minute after cooking but

oven lamp, blower motor and stirrer motors do not stop.

“EE 0” appear in display . “EE 16” appear in display. “EE 17” appear in display. “EE 8” appear in display . “EE 10” appear in display . Stirrer motors do not work.

AA BB CCCDDEEEEE F FGH

MAGNETRON MG1

MAGNETRON MG2

HIGH VOLTAGE TRANSFORMER T1

HIGH VOLTAGE TRANSFORMER T2

H.V. RECTIFIER ASSEMBLY FOR MG1

H.V. RECTIFIER ASSEMBLY FOR MG2

H.V. WIRE HARNESS

H.V. CAPACITOR C1

H.V. CAPACITOR C2

1ST. LATCH SWITCH

2ND. LATCH SWITCH

3RD. LATCH SWITCH

MONITOR SWITCH

STOP SWITCH

WEAK POINT A018 F3

WEAK POINT A018 F4

WEAK POINT A017 F1

FUSE 6.3A F2

R-2397

IIIIJLKKK LM NPQ

MAGNETRON THERMAL CUT-OUT 145˚C TC1

MAGNETRON THERMAL CUT-OUT 145˚C TC2

B. MOTOR THERMAL CUT-OUT 115˚C TC3

OVEN THERMAL CUT-OUTT 115˚C TC4

MONITOR RESISTOR R1

STIRRER MOTOR

MAGNETRON THERMISTOR

EXHAUST THERMISTOR

INTAKE THERMISTOR

OVEN LAMP OR SOCKET

BLOWER MOTOR

NOISE FILTER

POWER SUPPLY CORD

FUSE HOLDER

SHORTED WIRE HARNESS

OPENED WIRE HARNESS

TOUCH CONTROL PANEL

RELAY RY-1, RY-3, RY-4

FOIL PATTERN

BLOCKED VENTILATION OPENINGS

BLOCKED BLOWER MOTOR

MIS ADJUSTMENT OF SWITCHES

HOME FUSE OR BREAKER

NO POWER AT WALL OUTLET

OVER THE MAX. COOKING TIME

DUE TO PROGRAMME LOCK

TEMPERATURE OF EXHAUST THERMISTOR IS HIGH

TEMPERATURE OF INTAKE THERMISTOR IS HIGH

TEMPERATURE OF MAGNETRON THERMISTOR IS HIGH

BLOCKED STIRRER ANTENNA

KEY UNIT

R-2397

PROCEDURE

A MAGNETRON TEST

NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION.

CARRY OUT 3D CHECK. Isolate the magnetron from high voltage circuit by removing all leads connected to 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. To test for short filament to anode condition, connect ohmmeter between one of the filament terminals and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low or zero resistance reading is obtained then the magnetron should be replaced.

MICROWAVE OUTPUT POWER (IEC-705-1988)

The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted). Microwave output power from the magnetron can be measured by way of IEC 705, i.e. It is measured by how much power the water load can absorb. To measure the microwave output power in the microwave oven, the relation of calorie and watt is used. When P(W) heating works for t(second), approximately P x t/4.187 calorie is generated. On the other hand, if the temperature of the water with V(ml) rises ∆T (°C) during this microwave heating period, the calorie of the water is V x ∆T.

TEST PROCEDURES

LETTER

COMPONENT TEST

The formula is as follows;

P x t / 4.187 = V x ∆ T P (W) = 4.187 x V x ∆T / t

Our condition for water load is as follows:

Room temperature ......... around 20°C Power supply Voltage............... Rated voltage

Water load................ 1000 g Initial temperature..............10±2°C

Heating time ............ 25 sec. P=170x∆T

Measuring condition:

1. Container The water container must be a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190 mm.

2. Temperature of the oven and vessel The oven and the empty vessel are at ambient temperature prior to the start the test.

3. Temperature of the water The initial temperature of the water is (10±2)°C.

4. Select the initial and final water temperature so that the maximum difference between the final water temperature and the ambient temperature is 5K.

5. Select stirring devices and measuring instruments in order to minimize addition or removal of heat.

6. The graduation of the thermometer must be scaled by 0.1°C at minimum and can be accurate thermometer.

7. The water load must be (1000±5) g.

8. “t” is measured while the microwave generator is operating at full power. Magnetron filament heat-up time is not included.

NOTE: The operation time of the microwave oven is “t + 3” sec. (3 sec. is magnetron filament heat-

up time.) Therefore total reheating time = 28 seconds.

Measuring method:

1. Measure the initial temperature of the water before the water is added to the vessel. (Example: The initial temperature T1 = 11°C)

2. Add the 1 litre water to the vessel.

3. Place the load on the centre of the shelf.

4. Operate the microwave oven at HIGH for the temperature of the water rises by a value ∆ T of (10 ± 2) K.

5. Stir the water to equalize temperature throughout the vessel.

6. Measure the final water temperature. (Example: The final temperature T2 = 21°C)

7. Calculate the microwave power output P in watts from above formula.

PROCEDURE

1000g

T1˚C

T2˚C

D2 D1

ASYMMETRIC RECTIFIER

HIGH VOLTAGE RECTIFIER

R-2397

TEST PROCEDURES

LETTER

Initial temperature............................................................................................... T1 = 11°C

Temperature after (25 + 3) = 28 sec. ................................................................. T2 = 21°C

Temperature difference Cold-Warm ................................................................... ∆T = 10°C

Measured output power

The equation is “P = 170 x ∆T”.............................................. P = 170 x 10°C = 1700 Watts

JUDGMENT: The measured output power should be at least ± 15 % of the rated output power. CAUTION: 1°C CORRESPONDS TO 170 WATTS. REPEAT MEASUREMENT IF THE POWER IS

INSUFFICIENT.

COMPONENT TEST

Heat up for 28 sec.

B HIGH VOLTAGE TRANSFORMER TEST

WARNING: High voltages and large currents are present at the secondary winding and

filament winding of high voltage transformer. It is very dangerous to work near this part when the oven is on. NEVER make any voltage measurements of the high-voltage circuits, including the magnetron filament.

CARRY OUT 3D CHECKS.

Disconnect the leads to the primary winding of the high voltage transformer. Disconnect the filament and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a low range, it is possible to check the continuity of all three windings. The following readings should be obtained:

a. Primary winding approx. 1.06 Ω b. Secondary winding approx. 57.3 Ω c. Filament winding less than 1 Ω

If the reading obtained are not stated as above, then the high voltage transformer is probably faulty and should be replaced. CARRY OUT 4R CHECKS.

C HIGH VOLTAGE RECTIFIER ASSEMBLY TEST

HIGH VOLTAGE RECTIFIER TEST CARRY OUT 3D CHECKS.

Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.

The normal resistance is infinity in one direction and more than 100 kΩ in the other direction. CARRY OUT 4R CHECKS. ASYMMETRIC RECTIFIER TEST CARRY OUT 3D CHECKS.

R-2397

PROCEDURE

Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric rectifier can be tested using an ohmmeter set to its highest range. Contact the ohmmeter across the terminals A+B of the asymmetric rectifier and note the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is indicated in both directions then the asymmetric rectifier is good. If an asymmetric rectifier is shorted in either direction, then the asymmetric rectifier is probably faulty and must be replaced with high voltage rectifier. When the asymmetric rectifier is defective, check whether magnetron, high voltage rectifier, high voltage wire or filament winding of the high voltage transformer is shorted.

CARRY OUT 4R CHECKS. NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF

THE MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BECAUSE OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.

D HIGH VOLTAGE CAPACITOR TEST

CARRY OUT 3D CHECKS.

TEST PROCEDURES

LETTER

COMPONENT TEST

A. Isolate the high voltage capacitor from the circuit. B. Continuity check must be carried out with measuring instrument which is set to the highest

resistance range.

C. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ

after it has been charged. D. A short-circuited capacitor shows continuity all the time. E. An open capacitor constantly shows a resistance about 10 MΩ because of its internal 10MΩ

resistance. F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance. G. The resistance across all the terminals and the chassis must be infinite when the capacitor is

normal. If incorrect reading are obtained, the high voltage capacitor must be replaced.

CARRY OUT 4R CHECKS.

E SWITCH TEST

CARRY OUT 3D CHECK. Isolate the switch to be tested and using an ohmmeter check between the terminals as described

in the following table.

Plunger Operation COM to NO COM to NC NO; Normally open terminal

Released O.C. S.C. NC; Normally close terminal Depressed S.C. O.C. S.C.; Short circuit

If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.

Table: Terminal Connection of Switch COM;Common terminal

O.C.; Open circuit

CARRY OUT 4R CHECKS.

F WEAK POINT A018

CARRY OUT 3D CHECKS.

If the weak point A018 is blown, there could be a short in the asymmetric rectifier or there is a ground in wire harness. A short in the asymmetric rectifier may have occured due to short or ground in H.V. rectifier, magnetron, high voltage transformer or H.V. wire. Check them and replace the defective parts or repair the wire harness.

CARRY OUT 4R CHECKS.

CAUTION: Only replace weak point

A018 with the correct value replacement.

PROCEDURE

G WEAK POINT A017

CARRY OUT 3D CHECKS. If the weak point A017 is blown, there could be a shorts or grounds in electrical parts or wire harness.

Check them and replace the defective parts or repair the wire harness. CARRY OUT 4R CHECKS.

CAUTION: Only replace weak point A017 with the correct value replacement.

H FUSE F6.3A TEST

CARRY OUT 3D CHECKS. If the fuse F6.3A is blown when the door is opened, check the latch switch, monitor switch and

monitor resistor. If the fuse F6.3 is blown by incorrect door switching replace the defective switch(s) and the fuse F6.3A.

CARRY OUT 4R CHECKS.

TEST PROCEDURES

LETTER

COMPONENT TEST

R-2397

CAUTION: Only replace fuse with the correct value replacement.

I THERMAL CUT-OUT TEST

CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a

continuity test across the each two terminals as described in the table below. CARRY OUT 4R CHECKS.

Temperature of “ON” Temperature of “OFF” Indication of ohmmeter

Parts Name condition (closed circuit). condition (open circuit). (When room temperature

(˚C) (˚C) is approx. 20˚C.) Thermal cut-out 145˚C This is not resetable type. Above 145˚C Closed circuit. Thermal cut-out 115˚C This is not resetable type. Above 115˚C Closed circuit

If incorrect readings are obtained, replace the thermal cut-out. An open circuit oven thermal cut-out 115˚C indicates that the oven cavity has over heated, this may

be due to no load operation. An open circuit magnetron thermal cut-out 145˚C indicates that the magnetron has overheated, this

may be due to resistricted ventilation, cooling fan failure or a fault condition within the magnetron or HV circuit.

An open circuit blower motor thermal cut-out 115˚C indicates the blower motor winding has overheated, this may be due to resisted ventilation or locked cooling fan.

Table: Thermal Cut-out Test

J MONITOR RESISTOR TEST

CARRY OUT 3D CHECKS. Disconnect the leads from the monitor resistor. Using an ohmmeter and set on a low range. Check

between the terminals of the monitor resistor.

The resistance of monitor resistor should be read approx. 4.3Ω. If incorrect readings are obtained, replace the monitor resistor. CARRY OUT 4R CHECKS.

R-2397

PROCEDURE

K MAGNETRON THERMISTOR TEST

CARRY OUT 3D CHECKS. Disconnect connector-H from the CPU unit. Measure the resistance of the thermistor with an ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.

Room Temp. Resistance

If the meter does not indicate above resistance, replace the thermistor. CARRY OUT 4R CHECKS.

EXHAUST THERMISTOR TEST

CARRY OUT 3D CHECKS. Disconnect connector-B from the CPU unit. Measure the resistance of the thermistor with an

ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.

TEST PROCEDURES

LETTER

15˚C ........................Approx. 15.91 kΩ

20˚C ........................Approx. 13.04 kΩ

25˚C ........................Approx. 10.74 kΩ

COMPONENT TEST

Room Temp. Resistance

15˚C ........................Approx. 77.45 kΩ

20˚C ........................Approx. 61.47 kΩ

25˚C ........................Approx. 49.12 kΩ

If the meter does not indicate above resistance, replace the thermistor. CARRY OUT 4R CHECKS.

INTAKE THERMISTOR TEST

CARRY OUT 3D CHECKS. Disconnect connector-D from the CPU unit. Measure the resistance of the thermistor with an

ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.

Room Temp. Resistance

15˚C ........................Approx. 15.88 kΩ

20˚C ........................Approx. 13.03 kΩ

25˚C ........................Approx. 10.74 kΩ

If the meter does not indicate above resistance, replace the thermistor. CARRY OUT 4R CHECKS.

L MOTOR WINDING TEST

CARRY OUT 3D CHECKS. Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two terminals.

Resistance of Blower motor should be approximately 52Ω.

Resistance of Stirrer motor should be approximately 8.8 kΩ. If incorrect readings are obtained, replace the motor. CARRY OUT 4R CHECKS.

M NOISE FILTER TEST

CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of noise filter. Using an ohmmeter, check between the

terminals as described in the following table.

PROCEDURE

3 4

5 6

7 8 9

G 1

G 2G 3G 4

G 5

G 6

G 7

G 8

G 9

G 10

G 11

G 12

TEST PROCEDURES

LETTER

COMPONENT TEST

R-2397

WHT

BLK

MEASURING POINT INDICATION OF OHMMETER

Between N and L Open circuit Between terminal N and WHITW Short circuit Between terminal L and BLK Short circuit

If incorrect readings are absorbed, replace the noise filter.

CARRY OUT 4R CHECKS.

N TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, IC, 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 Switch Unit, troubleshooting by unit replacement is described

according to the symptoms indicated.

1. Key Unit The following symptoms indicate a defective key unit. Replace the key unit. a) When touching the pads, a certain pad produces no signal at all. b) When touching the pads, sometimes a pad produces no signal.

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

2-1 Programming problems.

a) When touching the pads, a certain group of pads do not produce a signal.

2-2 Display problems.

a) For a certain digit, all or some segments do not light up. b) For 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) Cooking is not possible.

Note: When defective components, (the Control Unit or Key Unit) are replaed, the defective part

or parts must be properly packed for return in the shipping carton. with its cushion material, in which the new replacement part was shipped to you.

L (min) Cx ± 20% Cy ± 20%

0.5mH 0.22 µF 4700 pF

O KEY UNIT TEST

f the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon is making good contact, verify that the door sensing switch (stop switch ) operates properly; that is the contacts are closed when the door is closed and open when the door is open. If the door sensing switch (stop switch ) is good, disconnect the flat ribbon cable that connects the key unit to the control unit and make sure the door sensing switch is closed (either close the door or short the stop switch connector ). Use the key unit matrix indicated on the control panel schematic and place a jumper wire between the pins that correspond to the STOP/CLEAR pad making momentary contact. If the control unit responds by clearing with a beep, the key unit is faulty and must be replaced. If the control unit does not respond, it is faulty and must be replaced.

R-2397

PROCEDURE

LETTER

P RELAY TEST

TEST PROCEDURES (CONT'D)

COMPONENT TEST

If a specific pad does not respond, the above method may be used (after clearing the control unit) to determine if the control unit or key pad is at fault.

CARRY OUT 3D CHECKS. Remove the outer case and check voltage between Pin Nos. 5 and 7 of the connector (A) on the

control unit with an A.C. voltmeter. The meter should indicate 230 volts, if not check control unit circuity.

RY1, RY3 and RY4 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. 19.0V D.C. Oven lamp, Blower motor and Stirrer motor RY3 APPROX. 16.0V D.C. Power transformer 1 RY4 APPROX. 18.0V D.C. Power transformer 2

CARRY OUT 4R CHECKS.

Q 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. If the foil pattern is open, follow the troubleshooting guide given below for repair.

Problem: POWER ON, indicator does not light up. CARRY OUT 3D CHECKS.

STEPS OCCURANCE CAUSE OR CORRECTION

1 The rated AC voltage is not present at Check supply voltage and oven power cord.

POWER terminal of CPU connector (CN-A).

2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.

side of low voltage transformer. Check and repair.

3 Only pattern at "a" is broken. *Insert jumper wire J24 and solder.

(CARRY OUT 3D CHECKS BEFORE REPAIR)

4 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".

(CARRY OUT 3D CHECKS BEFORE REPAIR)

NOTE: *At the time of these repairs, make a

visual inspection of the varistor for

D81

(J29)

burning damage and examine the transformer with tester for the presence of layer short-circuit (check primary coil resistance). If any abnormal condition is detected, replace the defective parts.

RY1

(J23)

(J24)

VRS1

(VRS2)

(9)9(7)5(3)3(1)

CARRY OUT 4R CHECKS.

TOUCH CONTROL PANEL ASSEMBLY

HIGH VOLTAGE TRANSFORMER

HIGH VOLTAGE CIRCUIT MAIN BODY SIDE

T/C SIDE

CT1 or CT2

RY3 or RY4

R61 or R62

R65 or R66

D61 or D62

R63 or R64

C61 or C62

IC1 IN3 or IN5 PORT

D63 or D64

OUTLINE OF TOUCH CONTROL PANEL

R-2397

The touch control section consists of the following units as shown in the touch control panel circuit.

(1) Control Unit (2) Key Unit

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

1. Control Unit

Signal of key touch and oven function control are all processed by one microcomputer.

1) Power Supply Circuit

This circuit changes output voltage at the secondary side of the low voltage (T1) transformer to volatges required at each part by full wave rectifying circuit, constant voltage circuit, etc..

2) ACL Circuit

This is an Auto-clear Circuit, i.e., a reset circuit, which enables IC1 to be activated from initial state.

3) Power SYNC Signal Generating Circuit

This is a circuit for generating power SYNC signal by virtue of the secondary side output of transformer T1. This signal is used for a basic frequency to time processing and so on.

4) Clock Circuit

This is a circuit for controlling clock frequency required for operating IC1.

5) IC1 (Main Processor)

This is a one-chip microcomputer, responsible for controlling the entire control unit.

6) IC2 (Memory Processor)

This is a memory IC, responsible for memory function.

7) Display Circuit

This is a circuit for driving display tubes by IC1 output.

8) Key Input Circuit

This is a circuit for transmitting key input information to IC1.

9) Sound-body Driving Circuit

This is a circuit for driving sound body by IC1 output.

10) Relay Driving Circuit

This is a circuit for driving output relay by IC1 output.

11) Stop Switch Circuit

This is a circuit for driving IC1 to detect door opening/ closing.

12) Exhaust Air Temperature Detecting Circuit

This is a circuit for transmitting output change of thermistor (Exhaust Air Temperature Sensor) to IC1.

13) High Voltage Monitoring Circuit.

This circuit detects problems in the magnetron / high voltage circuit by sensing a variation in the current flowing through the primary winding of the high voltage transformer. During heating, the primary current of the high voltage transformers also flows through the primary winding of the current transformers CT1 and CT2. This causes a current to be induced in the secondary windings of CT1/ CT2 and results in an AC voltage which is determined by R61/R62.

This AC voltage is then half wave rectified by D61/D62 and smoothed (filtered) by C61/C62. This AC voltage is the input to the IN3 and IN5 ports of IC1, which determines if there is a magnetron / high voltage problem.

Figure T-1. High Voltage Monitoring Circuit

14) Magnetron Temperature Circuit. (Detect Noload or Fan Lock)

This is a circuit for transmitting output change of thermistor (Magnetron Temperature Sensor) to IC1.

15) Intake Air Temperature Detecting Circuit.

This is a circuit for transmitting output change of thermistor (Intake Air Sensor) to IC1.

2. Key Unit

The key unit is composed of a matrix circuit in which when a key it touched, one of signals P11, P12, P15, P16 and P17 generated by the LSI, is passed through the key and returned to the LSI as one of signals R0--R3. This model has 20 Memory pads. When the oven is shipped, Memory pad 1 to 10 are set as follows: fig.1.

Memory No. Cook Time Output Power

1 5sec. 100% 2 10sec. 100% 3 20sec. 100% 4 30sec. 100% 5 40sec. 100% 6 50sec. 100% 7 1min. 100% 8 1min.15sec. 100% 9 1min.30sec. 100% 10 2min. 100%

(fig. 1)

This model has a double quantity pad. When the oven is shipped, Magnification "1.8" is preset in the double quantity pad. This model has an defrost pad. When the oven is shipped, defrost is set as follows: fig.2.

1 STAGE POWER 10% OVEN ON/OFF ON

(fig. 2)

R-2397

DESCRIPTION OF LSI

LSI(IZA646DR)

The I/O signal of the LSI(IZA646DR) is detailed in the following table.

Pin No. Signal I/O Description

1 VREF IN Reference voltage input terminal.

A reference voltage applied to the A/D converter in the LSI. Connected to GND.(0V)

2 IN7 IN

Temperature measurement input: MAGNETRON THERMISTOR.

By inputting DC voltage corresponding to the temperature detected by the thermistor, this input is converted into temperature by the A/D converter built into the LSI.

3 IN6 IN

Temperature measurement input: EXHAUST THERMISTOR.

By inputting DC voltage corresponding to the temperature detected by the thermistor, this

input is converted into temperature by the A/D converter built into the LSI. 4 IN5 IN A/D input for troubleshooting Magnetron 1. 5 IN4 IN

Terminal to change functions according to the model.

Signal in accordance with the model in operation is applied to set up its function. 6 IN3 IN A/D input for troubleshooting Magnetron 2. 7 IN2 IN Connected to GND.(0V) 8 IN1 IN Terminal not used. 9 IN0 IN

Temperature measurement input: INTAKE THERMISTOR.

By inputting DC voltage corresponding to the temperature detected by the thermistor, this

input is converted into temperature by the A/D converter built into the LSI.

10 P47 OUT Terminal not used. 11 P46 OUT Memory (EEPROM) clock output. 12 P45 IN/OUT Memory (EEPROM) data input/output.

13-14 P44-P43 OUT Magnetron high-voltage circuit driving signal.

To turn on and off the cook relay. In 100% power level operation, "L" level during cooking;

"H" level otherwise. In other power level operation (90,80,70,60,50,40,30,20,10 or 0%),

"H" and "L" level is repeated according to power level.

Power level ON OFF Power level ON OFF

100% 48sec. 0sec. 40% 22sec. 26sec.

90% 44sec. 4sec. 30% 16sec. 32sec. 80% 40sec. 8sec. 20% 12sec. 36sec. 70% 36sec. 12sec. 10% 8sec. 40sec. 60% 32sec. 16sec. 0% 0sec. 48sec. 50% 26sec. 22sec.

OFF

48 sec.

GND

-5V

15 P42 OUT Power supply output at thermistor detecting circuit.

(Output -5V in cooking only, but apply high impedance to others to prevent thermistor from

electrolytic corrosion ocurrence.)

16 P41 OUT Terminal not used. 17 P40 OUT

Oven lamp, Blower motor and Stirrer motor driving signal. (Square Waveform :

50Hz)

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

Square waveform voltage is delivered to the

RY1 relay driving circuit and

relays(RY3,RY4,COOK RELAY) control circuit.

18-22 P37-P33 OUT Terminal not used.

23 P32 OUT

Signal to sound buzzer.

This signal is to control the 2.5kHz continuous

signal.

A: key touch sound.

0.12 sec

1.2 sec B

20 msec

1.2 sec

B: Guydance sound. C: Completion sound.

200µsec.

24 P31 IN Signal synchronized with commercial power source frequency.

This is basic timing for all time processing of LSI.

25 P30 OUT Terminal not used. 26 CNVSS IN Connected to Vc.(-5V)

During cooking

20 msec

GND

-5V

200µsec.

2.4 sec

H : GND

L (-5V)

Pin No. Signal I/O Description

27 RESET IN Auto clear terminal.

Signal is input to reset the LSI to the initial state when power is supplied. Temporarily set to "L" level the moment power is supplied, at this time the LSI is reset. Thereafter set at "H" level.

28 XIN IN

Internal clock oscillation frequency setting input.

The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to XOUT terminal.

29 XOUT OUT

Internal clock oscillation frequency control output.

Output to control oscillation input of XIN.

30/31 XCIN/XCOUTIN/OUT Terminal not used.

32 VSS IN

Power source voltage: -5V.

VC voltage of power source circuit input. 33 ø OUT Terminal not used. 34 R3 IN

Signal coming from touch key.

When either one of G-12 line keys on key matrix is touched, a corresponding signal out

of P11, P12, P14-P17 will be input into R3. When no key is touched, the signal is held at

"L" level. 35 R2 IN

Signal similar to R3.

When either one of G-11 line keys on key matrix is touched, a corresponding signal will

be input into R2. 36 R1 IN

Signal similar to R3.

When either one of G-10 line keys on key matrix is touched, a corresponding signal will

be input into R1. 37 R0 IN

Signal similar to R3.

When either one of G-9 line keys on key matrix is touched, a corresponding signal will

be input into R0. 38 VP IN

Anode (segment) of Fluorescent Display light-up voltage: -31V

Vp voltage of power source circuit input.

R-2397

39 P17 OUT

40 P16 OUT

41 P15 OUT

42-43 P14-P13 OUT

44 P12 OUT

45 P11 OUT

Segment data signal.

The relation between signals and indicators are as follows:

Signal Segment Signal Segment

P24 .................. i P13 ..................... f

P23 ................j,k P12 ....................e

P17 ...............LB P11 .................... d

P16 .............. UB P10 .................... c

P15 ................. h P07 ....................b

ß(50Hz)

GND

-31(V)

P14 ................. g P06 ....................a

Key strobe signal.