Sharp R-222t carousel User manual

CHAPTER 1. BEFORE SERVICING

CHAPTER 2. WARNING TO SERVICE PERSONNEL

CHAPTER 3. PRODUCT SPECIFICATIONS

CHAPTER 4. APPEARANCE VIEW

CHAPTER 5. OPERATION SEQUENCE

CHAPTER 6. FUNCTION OF IMPORTANT COMPO-

NENTS

CHAPTER 7. TROUBLESHOOTING GUIDE

CHAPTER 8. TEST PROCEDURES

CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY

CHAPTER 10. COMPONENT REPLACEMENT AND

ADJUSTMENT PROCEDURE

CHAPTER 11. MICROWAVE MEASUREMENT

CHAPTER 12. CIRCUIT DIAGRAMS

Parts List

SERVICE MANUAL

R-222T(W)

CONTENTS

SHARP CORPORATION This document has been published to be used

for after sales service only.

The contents are subject to change without notice.

S7019R222TPJW

MICROWAVE OVEN

R-222T(W)

MODELS

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.

R-222T(W)

CONTENTS

CHAPTER 1. BEFORE SERVICING

[1] GENERAL IMPORTANT INFORMATION.....1-1

[2] CAUTION MICROWAVE RADIATION ........1-1

[3] WARNING ..................................................1-1

CHAPTER 2. WARNING TO SERVICE PERSONNEL

CHAPTER 3. PRODUCT SPECIFICATIONS

CHAPTER 4. APPEARANCE VIEW

[1] OVEN .........................................................4-1

[2] TOUCH CONTROL PANEL........................4-1

CHAPTER 5. OPERATION SEQUENCE

[1] OFF CONDITION .......................................5-1

[2] MICROWAVE COOKING CONDITION ......5-1

[3] POWER OUTPUT REDUCTION ................5-1

CHAPTER 6. FUNCTION OF IMPORTANT COMPO-

NENTS

[1] DOOR OPEN MECHANISM.......................6-1

[2] 1ST. LATCH SWITCH AND 2ND. INTER-

LOCK RELAY CONTROL SWITCH............6-1

[3] MONITOR SWITCH ...................................6-1

[4] FUSE T6.3A ...............................................6-1

[5] HIGH VOLTAGE FUSE ..............................6-1

[6] TEMPERATURE FUSE 150C (OVEN).......6-1

[7] TURNTABLE MOTOR ................................6-1

[8] FAN MOTOR ..............................................6-1

[9] NOISE FILTER ...........................................6-1

CHAPTER 7. TROUBLESHOOTING GUIDE

[1] FOREWORD ..............................................7-1

[2] CHART .......................................................7-1

CHAPTER 8. TEST PROCEDURES

[1] Procedure A : MAGNETRON (MG) TEST.....8-1

[2] Procedure B: POWER TRANSFORMER

TEST ..........................................................8-2

[3] Procedure C: HIGH VOLTAGE RECTIFI-

ER TEST ....................................................8-2

[4] Procedure D: HIGH VOLTAGE CAPACI-

TOR TEST..................................................8-2

[5] Procedure E: SWITCH TEST .....................8-3

[6] Procedure F: TEMPERATURE FUSE

TEST ..........................................................8-3

[7] Procedure G: MOTOR WINDING TEST.....8-3

[8] Procedure H: FUSE T6.3A .........................8-3

[9] Procedure I: NOISE FILTER TEST.............8-3

[10] Procedure J: HIGH VOLTAGE FUSE

TEST ..........................................................8-4

[11] Procedure K: TOUCH CONTROL PANEL

ASSEMBLY TEST ......................................8-4

[12] Procedure L: KEY UNIT (MEMBRANE

SWITCH) TEST ..........................................8-4

[13] Procedure M: RELAY TEST........................ 8-5

[14] Procedure N: PROCEDURES TO BE TAK-

EN WHEN THE FOIL PATTERN ON THE

PRINTED WIRING BOARD (PWB) IS

OPEN.......................................................... 8-5

CHAPTER 9. TOUCH CONTROL PANEL ASSEM-

BLY

[1] OUTLINE OF TOUCH CONTROL PANEL..... 9-1

[2] DESCRIPTION OF LSI ............................... 9-1

[3] SERVICING FOR TOUCH CONTROL

PANEL ........................................................ 9-3

[4] PRECAUTIONS FOR USING LEAD-

FREE SOLDER .......................................... 9-4

CHAPTER 10. COMPONENT REPLACEMENT AND

ADJUSTMENT PROCEDURE

[1] BEFORE OPERATING ............................. 10-1

[2] OUTER CASE REMOVAL ........................ 10-1

[3] POWER TRANSFORMER REMOVAL ..... 10-2

[4] HIGH VOLTAGE RECTIFIER ASSEMBLY,

HIGH VOLTAGE FUSE AND HIGH VOLT-

AGE CAPACITOR REMOVAL .................. 10-2

[5] MAGNETRON REMOVAL ........................ 10-2

[6] POSITIVE LOCK CONNECTOR (NO-

CASE TYPE) REMOVAL .......................... 10-2

[7] TURNTABLE MOTOR REMOVAL ............ 10-3

[8] COOLING FAN MOTOR REMOVAL......... 10-3

[9] POWER SUPPLY CORD REPLACE-

MENT........................................................ 10-4

[10] CONTROL PANEL ASSEMBLY REMOV-

AL ............................................................. 10-4

[11] GRAPHIC SHEET AND MEMBRANE

SWITCH REPLACEMENT........................ 10-4

[12] 1ST. LATCH SWITCH, 2ND. INTERLOCK

RELAY CONTROL SWITCH AND MONI-

TOR SWITCH ADJUSTMENT .................. 10-5

[13] 1ST. LATCH SWITCH, 2ND. INTERLOCK

RELAY CONTROL SWITCH AND MONI-

TOR SWITCH ADJUSTMENT .................. 10-5

[14] DOOR REPLACEMENT ........................... 10-6

CHAPTER 11. MICROWAVE MEASUREMENT

CHAPTER 12. CIRCUIT DIAGRAMS

[1] Oven Schematic ....................................... 12-1

[2] Pictorial Diagram (Figure S-1) .................. 12-2

[3] Control Unit Circuit (Figure S-2) ............... 12-3

[4] Printed Wiring Board (Figure S-3) ............ 12-4

Parts List

R-222T(W)

1 – 1

R200K Service Manual

CHAPTER 1. BEFORE SERVICING

[1] GENERAL IMPORTANT INFORMATION

This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information.

It is recommended that service engineers carefully study the entire text of this manual, so they will be qualified to render satisfactory customer ser-

vice.

[2] CAUTION MICROWAVE RADIATION

DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CON-

DUCTING 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.

[3] 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.

(D) The door is not deformed or warped.

(E) There is not any other visible damage with the oven.

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.

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

R-222T(W)

2 – 1

R200K Service Manual

CHAPTER 2. WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part of the high voltage circuit will result in

electrocution. High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage fuse, High voltage harness.

REMEMBER TO CHECK 3D

1) Disconnect the supply.

2) Door opened, and wedged open.

3) Discharge the high voltage capacitor.

WARNING: AGAINST THE CHARGE OF THE HIGH-VOLTAGE

CAPACITOR

The high-voltage capacitor remains charged about 60 sec-

onds after the oven has been switched off. Wait for 60 sec-

onds and then short-circuit 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 pri-

mary of the power transformer. Ensure that these leads remain iso-

lated 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 power transformer.

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 turntable, close the door and set the power level to HIGH

(100%). 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 3D checks 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 microwave leakage test

should be carried out.

R-222T(W)

3 – 1

R200K Service Manual

CHAPTER 3. PRODUCT SPECIFICATIONS

NOITPIRCSEDMET

Power Requirements

230 - 240 Volts

50 Hertz

Single phase, 3 wire earthed

Power Consumption 1.22 kW

Power Output 800 watts nominal of RF microwave energy (measured by method of IEC)

Operating frequency 2450 MHz

Case Dimensions

Width 460 mm

Height 275 mm including foot

Depth 380 mm

Turntable diameter 272 mm

Control Complement

Touch Control System

Timer (0 - 99 minutes 99 seconds)

Clock (1:00 - 12:59)

Microwave Power for Variable Cooking

Repetition Rate;

100P ................................................................ Full power throughout the cooking time

70P ................................................................................. approx. 70% of FULL Power

50P ................................................................................ approx. 50% of FULL Power

30P ................................................................................ approx. 30% of FULL Power

10P ................................................................................. approx. 10% of FULL Power

INSTANT ACTION pads

EXPRESS DEFROST pad

EASY DEFROST pad

NUMBER pads

TIMER/ CLOCK pad

INSTANT COOK/ START pad

POWER LEVEL pad

STOP/CLEAR pad

Set Weight (Approx.) 12 kg

R-222T(W)

4 – 1

R200K Service Manual

CHAPTER 4. APPEARANCE VIEW

[1] OVEN

1. Door open button

2. See-through door

3. Safety door latches

4. Door hinges

5. Door seals sealing surfaces

6. Coupling

7. Roller stay

8. Turntable

9. Ventilation openings

10.Oven lamp

11.Waveguide cover

12.Touch control panel

13.Liquid crystal display

14.Power supply cord

[2] TOUCH CONTROL PANEL

1. INSTANT ACTION PADS

Press to cook or reheat 5 popular menus.

2. NUMBER PADS

Press to enter cooking time, clock time, weight of food.

3. POWER LEVEL PAD

Press to select microwave power setting.

If not pressed, 100% is automatically selected.

Press to alter the cooking result for automatic operations.

4. TIMER/CLOCK PAD

Press to set clock, timer, child lock or demonstration mode.

5. STOP/CLEAR PAD

Press to clear during programming.

Press once to stop operation of oven during cooking; press twice to

cancel cooking programme.

6. INSTANT COOK/START PAD

Press once to cook for 1 minute at 100% or increase by 1 minute

multiples each time this pad is pressed during cooking.

Press to start oven after setting programmes.

7. EXPRESS DEFROST PAD

Press to select the Express Defrost menu.

8. EASY DEFROST PAD

Press to select the Easy Defrost menu.

NOTE: Some one-touch cooking features such as “INSTANT

COOK” are disabled after three minutes 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.

3 2

11 310

R-222T(W)

5 – 1

R200K Service Manual

CHAPTER 5. OPERATION SEQUENCE

[1] OFF CONDITION

Closing the door activates all door interlock switches (1st. latch switch,

2nd. interlock relay control 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, rated voltage is

supplied to the noise filter and the control unit.

Figure O-1 on page 12-1

1. The display will show flashing “88:88”.

2. To set any programmes or set the clock, you must first touch the

STOP/CLEAR key.

3. “ : “ appears in the display.

[2] MICROWAVE COOKING CONDITION

1. HIGH COOKING

Enter a desired cooking time by touching the NUMBER pads and start

the oven by touching START pad.

Function sequence

Figure O-2 on page 12-1

1. Rated voltage is supplied to the primary winding of the power trans-

former. 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 fila-

ment and the high voltage (2000 volts) is sent to the voltage dou-

bling circuit, where it is doubled to negative voltage of

approximately 4000 volts D.C..

3. The 2450 MHz microwave energy produced in the magnetron gen-

erates 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

(RY1+RY2) go back to their home position. The circuits to the oven

lamp, power transformer, fan motor and turntable motor are cut off.

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

the following condition

The circuits to the power transformer, fan motor, turntable motor and

oven lamp are cut off when the 1st. latch switch and 2nd. interlock

relay control switch are made open.

6. MONITOR SWITCH CIRCUIT

The monitor switch is mechanically controlled by oven door, and

monitors the operation of the 1st. latch switch and the 2nd. interlock

relay (RY2).

1) When the oven door is opened during or after the cycle of a

cooking program, the 1st. latch switch and 2nd. interlock relay

control switch must open their contacts first. After that the con-

tacts (COM-NC) of the monitor switch can be closed.

2) When the oven door is closed, the contacts (COM-NC) of the

monitor switch must be opened. After that the contacts of the

1st. latch switch and 2nd. interlock relay control switch are

closed.

3) When the oven door is opened and the contacts of the 1st. latch

switch and the 2nd. interlock relay (RY2) remain closed. The

fuse (T6.3A) will blow, because the monitor switch is closed and

a short circuit is caused.

2. MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW

COOKING

When the microwave oven is preset for variable cooking power, rated

voltage is supplied to the power transformer intermittently within a 32-

second time base through the relay contact which is coupled with the

current-limiting relay. The following levels of microwave power are

given.

SETTING;

NOTE: The ON/OFF time ratio does not exactly correspond to the

percentage of microwave power, because approx. 3 seconds

are needed for heating up the magnetron filament.

[3] POWER OUTPUT REDUCTION

After 100% power cooking mode is carried out for more than 20 min-

utes, the power out-put is automatically reduced to 70%. Even if the

cooking time is shorter than for 20 minutes, the power output is

reduced to 70% after total cooking time over 20 minutes when the

oven is started in 100% power cooking mode again within 1 minute

and 35 seconds.

CONNECTED COMPONENTS RELAY

Oven lamp, Fan motor, Turntable motor RY1

2YRremrofsnartrewoP

CONDITION

SWITCH CONTACT DURING

COOKING

DOOR OPEN

(NO COOKING)

1st. latch switch COM-NO Closed Open

2nd. interlock relay

control switch COM-NO Closed Open

Monitor switch COM-NC Open Closed

100P (HIGH)

32 sec. ON

70P

(MEDIUM

HIGH)

Approx. 70%

100%

24 sec. ON 8 sec. OFF

14 sec. OFF

20 sec. OFF

26 sec. OFF

%05.xorppA)MUIDEM(P05

18 sec. ON

30P

(MEDIUM

LOW)

Approx. 30%

12 sec. ON

%01.xorppA)WOL(P01

6 sec. ON

R-222T(W)

6 – 1

R200K Service Manual

CHAPTER 6. FUNCTION OF IMPORTANT COMPONENTS

[1] DOOR OPEN MECHANISM

The door is opened by pulling the door, refer to the Figure D-1.

Figure D-1. Door Open Mechanism

[2] 1ST. LATCH SWITCH AND 2ND. INTER-

LOCK RELAY CONTROL 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.

[3] MONITOR SWITCH

1. When the oven door is closed, the contacts (COM-NC) must be

opened.

2. When the oven door is opened, the contacts (COM-NC) must be

closed.

3. If the oven door is opened and the contacts (COM-NO) of the 1st

latch switch and the 2nd. interlock relay (RY2) fail to open, the fuse

(T6.3A) blows simultaneously with closing the contacts (COM-NC)

of the monitor switch.

CAUTION: BEFORE REPLACING A FUSE (T6.3A) TEST THE 1ST.

LATCH SWITCH AND 2ND. INTERLOCK RELAY (RY2)

AND MONITOR SWITCH FOR PROPER OPERATION.

(REFER TO CHAPTER “TEST PROCEDURE”.)

[4] FUSE T6.3A

1. The fuse (T6.3A) blows when the contacts (COM-NO) of the 1 st.

latch switch and the 2nd. interlock relay (RY2) remain closed with

the oven door open and when the monitor switch closes.

2. If the wire harness or electrical components are short-circuited, the

fuse (T6.3A) blows to prevent an electric shock of fire hazard.

[5] HIGH VOLTAGE FUSE

The high voltage fuse blows when the high voltage rectifier or the mag-

netron is shorted.

[6] TEMPERATURE FUSE 150C (OVEN)

The temperature fuse located on the top of the oven cavity is designed

to prevent damage to the oven if the foods in the oven catch fire due to

over heating produced by improper setting of cook time or failure of

control unit. Under normal operation, the temperature fuse remains

closed. However, when abnormally high temperatures are reached

within the oven cavity, the temperature fuse will open at 150°C, caus-

ing the oven to shut down. The defective temperature fuse must be

replaced with a new one.

[7] TURNTABLE MOTOR

The turntable motor drives the turntable roller assembly to rotate the

turntable.

[8] FAN MOTOR

The fan motor drives a blade which draws external cool air. This cool

air is directed through the air vanes surrounding the magnetron and

cools the magnetron. 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.

[9] NOISE FILTER

The noise filter prevents the radio frequency interference that might

flow back in the power circuit.

Latch

Heads

Door

Switch Lever

Latch Hook

Monitor Switch

2nd. Interlock

Relay Control

Switch

1 st. Latch

Switch

R-222T(W)

7 – 1

R200K Service Manual

CHAPTER 7. TROUBLESHOOTING GUIDE

[1] FOREWORD

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 Pro-

cedure”section.

IMPORTANT:

If the oven becomes inoperative because of a blown fuse T6.3A in the

1st. latch switch - 2nd. interlock relay (RY2) - monitor switch circuit,

check the 1st. latch switch, 2nd. interlock relay (RY2) and monitor

switch before replacing the fuse T6.3A.

[2] CHART

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE WIRE

HIGH VOLTAGE CAPACITOR

1ST. LATCH SWITCH

2ND. INTERLOCK RELAY CONTROL

SWITCH

MONITOR SWITCH

TEMPERATURE FUSE 150ºC (OVEN)

FAN MOTOR

TURNTABLE MOTOR

FUSE T6.3A

TOUCH CONTROL PANEL

RELAY (RY-1)

RELAY (RY-2)

FOIL PATERN ON P.W.B.

POWER SUPPLY CORD

SHORTED WIRE HARNESS

OPENED WIRE HARNESS

OVEN LAMP

WALL OUTLET

MISADJUSTMENT SWITCH

HOME FUSE OR BREAKER

BLOCKED COOLING FAN

BLOCKED VENTILATION

NOISE FILTER

KEY UNIT (MEMBREANE SWITCH)

H.V. FUSE

OFF

CONDITION

PROBLEM

CONDITION

POSSIBLE CAUSE

AND

DEFECTIVE PARTS

TEST PROCEDURE

CONDITION

A B C

D E JLINMKHGGFEE M

RE CK CK RE CK CK CK CK CK

Home fuse blows when pow-

ersupply cord is plugged into

wall outlet.

FUSE T6.3A blows when

power supply cord is plug-

ged into wall outlet.

"88:88" does not appear in

display but power supply cord

is plugged into wall outlet.

Display does not operate

properly when STOP/CLEAR

pad is touched.

Oven does not start when

the START pad is touched.

(Display appears)

Oven lamp does not light

(Display appears.)

Fan motor does not operate.

(Display appears.)

Turntable motor does not

operate. (Display appears.)

Oven or any electrical parts

does not stop when cooking

time is 0 or STOP/CLEAR

pad is touched.

Oven seems to be operating

but little or no heat is pro-

duced in oven load. (Micro-

wave power level is set at

100%)

Oven does not seems to be

operating properly when

70%,50%, 30% or 10% is

set. (Oven operates properly

at 100%.)

Oven goes into cook cycle

bu tshuts down before end

of cooking cycle.

R-222T(W)

8 – 1

R200K Service Manual

CHAPTER 8. TEST PROCEDURES

[1] Procedure A : MAGNETRON (MG) TEST

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

CARRY OUT 3D CHECKS.

Isolate the magnetron from the high voltage circuit by removing all leads connected to the filament terminal.

To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron filament terminals, the meter should show a

reading of less than 1 ohm.

To test for a short circuit 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 (1 litre water load)

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 IEC test procedure, i.e. it can be measured by using water load how much it can be absorbed by the water

load. 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(sec-

ond), 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.

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 of the test.

3) Temperature of the water

The initial temperature of the water is (10±1)°C

4) Select the initial and final water temperature so that the maximum difference between the final water temperature and the ambient temperature is

5°C.

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 an 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.

Measuring method:

1) 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 100% for the temperature of the water rises by a value T of 10°C.

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.

JUDGEMENT: The measured output power should be at least ±15 % of the rated output power.

CAUTION: 1°C CORRESPONDS TO 80 WATTS. REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.

The formula is as follows;

P x t / 4.187 = V x T+ 0.55 x mc (T2-T0)/4.187 P (W) = 4.187 x V x T / t + 0.55 x mc (T2-T0)/t

Our condition for water load is as follows:

Room temperature (T0) ......................... around 20°C Power supply ........................... VoltageRated voltage

Water load .........................................................1000 g Initial temperature (T1) .................................... 10±1°C

Heating time ..................................................... 52 sec. Mass of container (mc) ...................................... 330 g

T2 .................................................... Final Temperature T = T2 - T1 P = 80 x T + 0.55 x mc (T2-T0)/52

Room temperature ................................................................... To = 21°C

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

Temperature after (52 + 3) = 55 sec ...................................... T2 = 21°C

Temperature difference Cold-Warm ( T = T2 - T1) .......... T = 10°C

Measured output power

The equation is "P = 80 x T" .................... P = 80 x 10°C = 800 Watts

R-222T(W)

8 – 2

[2] Procedure B: POWER TRANSFORMER TEST

1. CARRY OUT 3D CHECKS.

2. Disconnect the leads to the primary winding of the power 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 winding. The following readings should be

obtained:

a.Primary winding -------------------- 2.8 ohms approximately

b.Secondary winding --------------- 204 ohms approximately

c.Filament winding ------------------------------ less than 1 ohm

If the readings obtained are not stated as above, then the power transformer is probably faulty and should be replaced.

3. Also, the power transformer has the thermal cut-out in the primary coil. The thermal cut-out will open when the temperature of the thermal cut-out

in the primary coil reaches approximately 150°C. The thermal cut-out resets automatically at 130°C. If an ohmmeter indicates an open circuit

under normal condition, replace the power transformer because the primary coil (thermal cut-out) has opened. An open primary coil (thermal cut-

out) indicates overheating of the power transformer. Check for restricted air flow to the power transformer, especially the ventilation opening.

4. CARRY OUT 4R CHECKS.

[3] Procedure C: 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 of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this second

reading. The normal resistance is infinite in one direction and more than 100 kΩin the other direction.

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 DIRECTION.

[4] Procedure D: HIGH VOLTAGE CAPACITOR TEST

CARRY OUT 3D CHECKS.

1. Isolate the high voltage capacitor from the circuit.

2. Continuity check must be carried out with measuring instrument which is set to the highest resistance range.

3. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩafter it has been charged.

4. A short-circuited capacitor shows continuity all the time.

5. An open capacitor constantly shows a resistance about 10 MΩbecause of its internal 10MΩresistance.

6. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.

7. 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.

WARNING: High voltages and large currents are present at the secondary winding and filament winding of the power transformer. It is

very dangerous to work near this part when the oven is on. NEVER make any voltage measurements of the high-voltage cir-

cuits, including the magnetron filament.

1000g

T1 C T2 C

Heat up for 55 sec.

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8 – 3

[5] Procedure E: SWITCH TEST

CARRY OUT 3D CHECKS.

Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the following table.

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

CARRY OUT 4R CHECKS.

[6] Procedure F: TEMPERATURE FUSE TEST

CARRY OUT 3D CHECKS.

Disconnect the leads from the terminals of the temperature fuse. Then using an ohmmeter, make a continuity test across the two terminals as

described in the below.

If incorrect readings are obtained, replace the temperature fuse.

An open circuit temperature fuse (OVEN) indicates that the food in the oven cavity may catch fire, this may be due to overheating produced by

improper setting of the cooking time or failure of the control panel.

CARRY OUT 4R CHECKS.

[7] Procedure G: MOTOR WINDING TEST

CARRY OUT 3D CHECKS.

Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two terminals as described in the table below.

If incorrect readings are obtained, replace the motor.

CARRY OUT 4R CHECKS.

[8] Procedure H: FUSE T6.3A

CARRY OUT 3D CHECKS.

If the fuse T6.3A is blown when the door is opened, check the 1st. latch switch, 2nd. interlock relay (RY2) and monitor switch.

If the fuse T6.3A is blown by incorrect door switching replace the defective switch(es) and the fuse T6.3A.

If the fuse T6.3A is blown, there is 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 FUSE T6.3A WITH THE CORRECT VALUE REPLACEMENT.

[9] Procedure I: NOISE FILTER TEST

CARRY OUT 3D CHECKS.

Disconnect the leads from the terminals of the noise filter. Using an ohmmeter, check

between the terminals as described in the following table.

If incorrect readings are obtained, replace the noise filter unit.

CARRY OUT 4R CHECKS.

Table: Terminal Connection of Switch

Plunger Operation COM to NO COM to NC COM; Common terminal

Released Open circuit Short circuit NO; Normally open terminal

Depressed Short circuit Open circuit. NC; Normally close terminal

Table: Temperature Fuse Test

Parts Name Temperature of “ON” condition

(closed circuit).

Temperature of “OFF” condition

(open circuit).

Indication of ohmmeter (When room

temperature is approx. 20°C.)

Temperature fuse 150°C This is not resetable type. Above 150°tiucricdesolCC

Table: Resistance of Motor

Motors Resistance

Fan motor Approximately 250 Ω

Turntable motor Approximately 14.7 kΩ

MEASURING POINT INDICATION OF OHMMETER

Between N and L Open circuit

Between terminal N and WHITE Short circuit

Between terminal L and RED Short circuit

RED

WHT

FUSE

T6.3A

NOISE SUPPRESSION COIL

NOISE FILTER

R200K

8 – 4

[10] Procedure J: HIGH VOLTAGE FUSE TEST

CARRY OUT 3D CHECKS.

If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.

Check them and replace the defective parts and the high voltage fuse.

CARRY OUT 4R CHECKS.

CAUTION: ONLY REPLACE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE REPLACEMENT.

[11] Procedure K: 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, CPU Unit and Power Unit, and troubleshooting by unit replacement

is described according to the symptoms indicated.

1. Key Unit. Note: Check key unit ribbon connection before replacement.

The following symptoms indicate a defective key unit. Replace the key unit.

1) When touching the pads, a certain pad produces no signal at all.

2) When touching a number pad, two figures or more are displayed.

3) When touching the pads, sometimes a pad produces no signal.

2. Control Unit.

The following symptoms indicate a defective control unit. Before replacing the control unit, perform the Key unit test (Procedure L) to determine if

control unit is faulty.

1) In connection with pads.

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

b) When touching the pads, no pads produce a signal.

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 up.

d) The corresponding segments of all digits do not light up; or they continue to light up.

e) Wrong figure appears.

f) A certain group of indicators do not light up.

g) The figure of all digits flicker.

3) Other possible troubles 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.

[12] Procedure L: KEY UNIT (MEMBRANE SWITCH) TEST

1. CARRY OUT 3D CHECKS.

2. Isolate the key unit with the control panel frame to be tested.

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

ter 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.

4. CARRY OUT 4R CHECKS.

Pin NO. G1 Pin NO. G10

Key unit ribbon

cable

Key unit (Membrane Switch) front view

G4 G5 G6G1

G10

G2 G3

TIMER

CLOCK

INSTANT COOK

EASY

DEFROST

FROZEN

VEGETABLES

JACKET

POTATO BEVERAGE

DINNER

PLATE

POWER

LEVEL

EXPRESS

DEFROST

FRESH

VEGETABLES

STOP

CLEAR

START

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8 – 5

[13] Procedure M: RELAY TEST

CARRY OUT 3D CHECKS.

Remove the outer case and check voltage between the Pin No. 1 of 3 pin connector (A) and the normal open terminal of the relay RY2 on the control

unit with an A.C. voltmeter. The meter should indicate 230 - 240 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, control unit is defective.

CARRY OUT 4R CHECKS.

[14] Procedure N: 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.

NOTE: *At the time of making these repairs, make a visual inspection of the varistor.

Check for burned damage and examine the transformer with a tester for the

presence of layer short-circuit (check the primary coil resistance). If any

abnormal condition is detected, replace the defective parts.

CARRY OUT 4R CHECKS.

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY1 Approx. 13.9 D.C. Oven lamp / Turntable motor / Cooling fan motor

RY2 Approx. 12.7V D.C. Power transformer

NOITCERROCROESUACECNERRUCCOSPETS

1The rated AC voltage is not present Pin No. 1 of 3 pin connector (A) and the

normal open terminal of the relay RY2. Check supply voltage and oven power cord.

2 The rated AC voltage is present to primary side of low voltage transformer. Low voltage transformer or secondary circuit defective.

Check and repair.

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9 – 1

R200K Service Manual

CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY

[1] OUTLINE OF TOUCH CONTROL PANEL

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

the touch control panel circuit.

(1) Key Unit (2) Control Unit

The principal functions of these units and their related signals are

explained below.

1. Key Unit

The key unit is composed of a matrix, signals generated in the LSI are

sent to the key unit through P24, P25, P26, P31, P32 and P33. When

a key pad is touched, a signal is completed through the key unit and

passed back to the LSI through P50, P51, P52 and P53 to perform the

function that was requested.

2. Control Unit

Control unit consists of LSI, reset circuit, indicator circuit, power

source circuit, relay circuit, buzzer circuit and synchronizing signal cir-

cuit.

1) Reset Circuit

This circuit generates a signal which resets the LSI to the initial

state when power is supplied.

2) Indicator Circuit

This circuit consists of 4-digits, 12-segments and 3-common elec-

trodes using a Liquid Crystal Display.

3) Power Source Circuit

This circuit generates voltage 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.

4) Relay 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 com-

pose a basic standard time in the clock circuit. It accompanies a

very small error because it works on commercial frequency.

7) 2nd. Interlock Relay Control Switch

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

[2] DESCRIPTION OF LSI

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

Symbol Voltage Application

VSS -5V LSI(IC1)

noitpircseDO/IlangiS.oNniP

1 P50 IN Signal coming from touch key.

When either G7 line on key matrix is touched, a corresponding signal out of P24 - P26 and P31 - P33 will be

input into P50. When no key is touched, the signal is held at "H" level.

2 P51 IN Signal similar to P50.

When either G8 line on key matrix is touched, a corresponding signal will be input into P51.

3 P52 IN Signal similar to P50.

When either G9 line on key matrix is touched, a corresponding signal will be input into P52.

4 P53 IN Signal similar to P50.

When either G10 line on key matrix is touched, a corresponding signal will be input into P53.

5 IC IN Connected to VSS.

6 XT1 IN Connected to VSS.

7 XT2 Terminal not used.

8 VDD IN Power source voltage input terminal.

The power source voltage to drive the LSI. Connected to GND.

9 VSS IN Power source voltage input terminal.

The power source voltage to drive the LSI.

10 X1 IN Internal clock oscillation frequency input setting.

The internal clock frequency is set by inserting the resistor-capacitor oscillation circuit with respect to X2 termi-

nal.

11 X2 OUT Internal clock oscillation frequency control output.

Output to control oscillation input of X1.

12 RESET IN Auto clear terminal.

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

13-15 P00-P02 OUT Terminal not used.

16 P03 OUT Terminal not used.

17 CAPH - Terminal not used.

18 CAPL - Terminal not used.

19-21 VLC0-VLC2 IN Power source voltage input terminal.

Standard voltage for LCD.

22 COM0 OUT Common data signal.

Connected to LCD signal COM0.

23 COM1 OUT Common data signal.

Connected to LCD signal COM1.

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9 – 2

24 COM2 OUT Common data signal.

Connected to LCD signal COM2.

25 COM3 OUT Terminal not used.

26-37 SEG0-SEG11 OUT Segment data signal.

Connected to LCD.The relation between signals are as follows:

LSI signal (Pin No.) LCD (segment) LSI signal (Pin No.) LCD (segment)

SEG 0 (26) ----------------- SEG 1 SEG 6 (32) ----------------- SEG 7

SEG 1 (27) ----------------- SEG 2 SEG 7 (33) ----------------- SEG 8

SEG 2 (28) ----------------- SEG 3 SEG 8 (34) ----------------- SEG 9

SEG 3 (29) ----------------- SEG 4 SEG 9 (35) ----------------- SEG 10

SEG 4 (30) ----------------- SEG 5 SEG 10 (36) ----------------- SEG 11

SEG 5 (31) ----------------- SEG 6 SEG 11 (37) ----------------- SEG 12

38-40 SEG12-SEG14 OUT Terminal not used.

41 P70 OUT Oven lamp, fan motor and turntable motor driving signal

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

waveform voltage is delivered to the RY1 driving circuit

and RY2 control circuit.

42 P71 OUT Terminal not used.

43 P72 OUT Magnetron high-voltage circuit driving signal.

To turn on and off the cook relay (RY2). The signals

holds "L" level during microwave cooking and “H” level

while not cooking. In other cooking modes (variable

cooking) the signal turns to “H” level and “L” level in rep-

etition according to the power level.

44 AVDD IN A/D converter power source voltage.

The power source voltage to drive the A/D converter in the LSI. Connected to GND.

45-47 AIN5-AIN3 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.

48-50 AIN2-AIN0 IN This is the terminal to detect the voltage of the signal coming from the touch key.

51 AVSS IN A/D converter power source voltage.

The power source voltage to drive the A/D converter in the LSI.

52 P11 IN To input signal which communicates the door open/close information to LSI.

Door close “H” level signal (0V). Door open “L” level signal (-5V)

53 P10 OUT Terminal not used.

54 P33 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal while one of G1