Sharp R-7a53 User manual

R-7A53

SHARP

SERVICE MANUAL

S8107R7A53J//

CONVECTION

MICRW-VE

0)&N

.

In

interests

of

user-safety

the

oven

should

be

restored

to

its

original

condition

and

only

manufacturer

original

spare

parts

m&t

be used.

This

is

a

supplemental

Service

Manual

for

Model

R-7A53.

This

model

is

quite

similar

to

Base

Model

R-7H52

(Refer

No. is

SX007R7A52PJZ).

Use

this

supplemental

manual

together

with

the

Base

Model

Service

Manual.

Refer

to

the

Base

Model

Service

Manual

for

complete

operation,

service

information,

etc.

TABLE

OF

CONTENTS

Page

CAUTION,

MICROWAVE

RADIATION

..........................................................................................................

1

GENERAL

IMPORTANT

INFORMATION

......................................................................................................

1

WARNING

..........................................................................................................................................................

1

PRODUCT SPECIFICATIONS .........................................................................................................................

2

APPEARANCE VIEW ........................................................................................................................................

3

GENERAL

INFORMATION

..............................................................................................................................

3

TEST

PROCEDURE ...........................................................................................................................................

4

WIRING DIAGRAM

..........................................................................................................................................

7

PICTORIAL DIAGRAM

.....................................................................................................................................

8

CONTROL

PANEL

CIRCUIT

............................................................................................................................

9

PRINTED

WIRING

BOARD .......................................................................................................................... 10

PARTS

LIST ....................................................................................................................................................

11

PACKING

AND

ACCESSORIES

....

...............................................................................................................

17

SHARP

CORPORATION

R-7A53

.

R-7A53

SERVICE

MANUAL

SHARP

CONVECTION MICROWAVE OVEN

R-7A53

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

and

base

model

manual,

so

they

will

be

qualified

to

render

satisfactory

customer

service.

r

CAUTION

MICROWAVE

RADIATION

Service

engineers

should

not

be

exposed

to

the

micro-

wave

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.

(9)

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.

Servicing

and

repair

work

must

be

carried

out

only

by

trained

service

engineers.

All

the

parts

marked

*ln

on

parts

list

are used

at

voltages

more

than

250V.

SHARP

CORPORATlON

OSAKA,

JAPAN

1

PRODUCT

SPECIFICATIONS

APPEARANCE

VIEW

TEST

PROCEDURE

WIRING

DIAGRAM

*.

PICTORIAL

DIAGRAM

PARTS

LIST

R-7A53

PRODUCT

SPECIFICATIONS

ITEM

Power

Requirements

Power

Consumption

Power

Output

Convection

heater

Power

output

Case

Dimensions

Cookina

Cavitv

Dimensions

Turntable

diameter

Control

Complement

l

Set

Weight

SPECIFICATION

DESCRIPTION

240

Volts

50

Hertz

Single

phase,

3

wire

earthed

Microwave

cooking

1.5 kW

Approx.

6.5A

Convection

cooking

1.6 kW

Approx.

6.7A

850W

(IEC-705-1988)

r/750

watts

nominal

of

RF

microwave

energy

(2

litre

water

load)

Operating

frequency

of

2450MHz

1.5kW

Width

520mm

Height

338mm Depth

469mm

Width

346

mm

Height

222

mm

Depth

350

mm

330mm x

Touch

Control

System

Clock(

I:00

-

12:59

)

Timer

(0

-

99

minutes

99

seconds

)

Microwave

Cooking

Control

Repetition

Rate;

HIGH

.

Full

power

throughout

the

cooking

time

MEDIUM

HIGH

.

approx.

70%

of

Full

Power

MEDIUM

.

approx.

50%

of

Full Power

MEDIUM

LOW

.

approx.

30%

of

Full Power

LOW

.

approx.

10%

of

Full Power

Convection

temperature

Control

Range;

4O”C, 7O”C, 13O”C, 15O”C, 16O”C,

18O”C,

2OO”C,

22O”C,

230°C

and

250°C

LOW

MIX/BAKE:

180°C

with

10%

microwave

power

HIGH

MIX/BAKE:

200°C

with

30%

microwave

power

GRILL: 250°C

(PREHEAT)

SLOW

COOK:

130°C

for

4

hours

(NO

PREHEAT)

MULTI

COOK, EASY REHEAT, EASY DEFROST,

MEMORY

HIGH

MIX/ROAST,

LOW

MIX/BAKE,

CONVECTION

GRILL,

NUMBER

AND

TEMPERATURE

VARIABLE

COOKING

CONTROL,

MORE/LESS,

SLOW

COOK

AUTO

START/CLOCK,

INSTANT

COOK/START,

STOP/CLEAR

Approx.

24.0

kg

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

(RD51107L

‘)

2

R-7A53

APPEARANCE

VIEW

1.

Ventilation

openings

7.

Waveguide

Cover

13.

Roller

stay

*

Place

the

roller

stay

on

the

2.

Hinges

8.

Touch

Control

Panel 14.

Turntable coupling

in

the

oven

and

seat

3.

Safety

door

latches

9.

Digital

display

15.

Low

rack

the

turntable

on

the

roller

4.

See

through

door

10.

Oven

lamp 16.

High

rack

stay.

5.

Coupling

11.

Access

cover

for

oven

6.

Door

open

button

lamp

replacement

12.

Power

supply

cord

Touch Control Panel

MULTI

COOK

PAD

Touch

to

select

Multi

Cook

mode

MULTI

COOK

FUNCTION

PADS

tion.

NUMBER

AND

TEMPERATURE

clock

time,

convection

tem-

perature

or

to

select

the

Multi

Cook

menus.

ly

used

cookrng

programme.

Touch

to

recall

the

memorized

programme.

VARIABLE

COOKING

CON-

TROL

PADS

Touch

to

select

microwave

power

setting.

If

not

touched,

HIGH

is

automatically

se-

lected.

STOP/CLEAR

PAD

Touch

to

erase

during

pro-

gramming.

Touch

once

to

stop

operation

of

oven

during

cooking;

touch

twice

to

can-

cel

cooking

programme.

AUTO

START/CLOCK

PAD-

Touch

to

set

clock

or

auto

start

time.

-

iINSTANT

ACTION

PADS

Touch

once

to

cook

or

reheat

4

popular

menu.

-2

SERVE

QUANTITY

PAD

To

cook

two

serves,

touch

this

pad

prior

to

touching

the

INSTANT

ACTION

pad.

-3

SERVE

QUANTITY

PAD

To

cook

three

serves,

touch

this

pad

prior

to

touching

the

INSTANT

ACTION

pad.

4

SERVE

QUANTITY

PAD

To

cook

four

serves,

touch

this

pad

prior

to

touching

the

INSTANT

ACTION

pad.

EASY

DEFROST

PAD

Touch

to

defrost

meat

by

en-

tering

weight

only.

MORE{

~1,

LESS(v)

PADS

Touch

to

increase/decrease

the

time

in

one

minute

tncre-

ments

during

cooking

or

to

alter

the

doneness

for

the

Ins-

tant

Action,

Multi

Cook

or

Easy

Defrost

modes.

-INSTANT

COOK/START

PAD

Touch

once

to

cook

for

1

minute

at

HIGH

or

increase

by

1

minute

multiples

each

time

this

pad

is

touched

during

microwave,

convection,

grill

or

mix

cooking.

I

R-7A53

TEST PROCEDURES

PROCEDURE

LETTER COMPONENT TEST

AMAGNETRON 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

fil-

ament

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.

(RD82AOl

U)

MICROWAVE OUTPUT POWER (2 liter water load)

The

following

test

procedure

should

be

carried

out

with

the

microwave

oven

in

a

fully

assembled

condition

(with

outer

case

fitted).

Microwave

output

power

from

the

magnetron

can be

measured

by

way

of

substitution,

i.e.

it

can be

measured

by

using

a

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(second),

approximately

P

x

t/4.2

calorie

is

generated.

On

the

other

hand,

if

the

temperature

of

the

water

with

V(ml)

rises

AT

(“C)

during

this

microwave

heating

period,

the

calorie

of

the

water

is Vx

AT.

The

formular

is

as

follows;

Pxt/4.2=VxAT

P

(W)

=

4.2

x

V

x

AT

/

t

Our

condition

for

the

water

load

is as

follows:

Room temperature

.

around

20°C Power

supply

Voltage

.

240

volts

Water

load

.

...2000

ml

Initial

temperature

.

10

+I

“C

Heating

time

.

1

min.

52

sec.

P

=

75

x

AT

J

Measuring

method:

A)

Use

two

1

litre

Pyrex

beakers

with

a

diameter

of

approximately

of

12cms.

B)

Place

1

litre

of

10°C

water

in

each

beaker.

C)

Mark

Tl

on

the

one

beaker

and

mark

T2

on

the

other

one.

And

stir

the

water

and

measure

the

temperature

of

water

the

thermometer

and

note

them.

The

graduation

of

the

thermometer

must

be

scaled

by

0.1

“C

at

minimum

and

an

accurate

mercury

thermometer

is

recommended.

D)

Place

the

two

beakers

as

touching

each

other

in

the

centre

of

the

cavity.

E)

Set

the

timer

to

1

minute

52

seconds

at

100%

power

(the

time

required

to

raise

the

water

temperature

IO

degrees

C.)

F)

The

time

must

be

measured

with

stopwatch

or

wristwatch.

G)

After

1

minute

and

52

seconds,

stop

the

oven

by

opening

the

door.

H)

Remove

the

two

beakers

from

the

oven

and

measure

the

temperature

of

the

water

by

stiring

the

water

with

the

thermometer

and

noting

the

readings.

Example

Initial

temperature

.

Tl

=

10°C

T2

=

11

“C

Temperature

after

1

min.

52

sec. ._..._....._............................................

Tl

=

20°C

T2

=

21

“C

Temperature

difference

Cold-Warm

AT1 =

.

10°C AT2

=

10°C

Mean

temperature

rise

AT

.

AT

=(AT1

+AT2)

/

2

=

(10°C

+

10°C)

/

2

=

10°C

Measured

output

power

The

equation

is

“P=

75

x

AT”

.

.._......._................................

P=

75

x

10°C

=

750

Watts

NOTE: The measured output power should be at least

+15

%

of the rated output

power.

CAUTION:

1

“C

CORRESPONDS

TO

75

WATTS.

REPEAT

MEASUREMENT

IF THE POWER IS

INSUFFICIENT.

4

R-7A53

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER COMPONENT TEST

(Tl

“CI

(T2

OC)

Heat

up

for

1

min.

52

sec.

MICROWAVE OUTPUT POWER

(IEC-705-1988)

(RD82AOZU)

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

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

cal-

orie

and

watt

is used.

When

P(W)

heating

works

for

t(second),

approximately

P

x

t/4.1

87

calorie

.

is

generated.

On

the

other

hand,

if

the

temperature

of

the

water

with

V(ml)

rises

AT

(“C)

during

this

microwave

heating

period,

the

calorie

of

the

water

is V

x

AT.

The

formular

is

as

follows;

Pxt/4,187=VxAT P(W)=4,187xVxAT/t

Our

condition

for

the

water

load

is

as

follows:

Room

temperature

.

around

20°C

Power

supply

Voltage

.

240

volts

Water

load

.

1000

g

Initial

temperature

.

10

+

2°C

Heating

time

.

49

sec.

P=85xAT

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

fest.

3.

Temperature

of

the

water

The

initial

temperature

of

the

water

is

(10

+

2)X

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

O.l”C

at

minimum

and

an

accurate

thermometer.

7.

The

water

load

must

be

(1000

f

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

+

2”

sec.

2

sec. is

magnetron

filament

heat-up

time.

5

R

-7A53

TEST PROCEDURES (CONT’D)

PROCEDURE

LETTER COMPONENT TEST

Measuring

method:

1.

Measure

the

initial

temperature

of

the

water

before

the

water

is

added

to

the

vessel.

(Example:

The

initial

temperature

Tl

=

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

A

T

of

(IO

+

2)

“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.

Caluculate

the

microwave

power

output

p

in

watts

from

above

formula.

I

Initial

temperature

.

.._._......................................................................

Tl

=

11

“C

/

Temperature

after (49

+

2)

=

51

sec.

.

T2

=

21

“C

Temperature

~

M

difference Cold-Warm

=

.

AT1 10°C

easured

output

power

!

The

equation

is

“P=

85

x

AT”

.

...’

.

P= 85

x

10°C

=

850

Watts

JUDGMENT: The measured output power should be at least

f15

%

of

t?he

rated

.

output power.

CAUTION:

1°C

CORRESPONDS

TO

85

WATTS. REPEAT

MEASUREMENT

IF

THE POWER

IS

INSUFFICIENT.

1

ooog

+

T2’C

Heat

up

for

51

sec.

(RDE

\03U)

B

POWER TRANSFORMER TEST

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

ing

and

filament winding of the power transformer. It is very dan-

gerous 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

3LJ

CHECKS.

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

windings.

The

following

readings

should

be

obtained

:-

a.

Primary

winding

----------I

.20

ohms

approximately.

b.

Secondary

winding

-------75.5

ohms

approximately.

c.

Filament

winding

---------less

than

1

ohm.

If

the

reading

obtained

are

not

as

stated

above,

then

the

power

transformer

is

probably

faulty

and

should

be

replaced.

CARRY

OUT

4R

CHECKS

6

a

h

240V-50Hr

44

240V--5OHr

2

CLOCK

APPEARS

ON

DISPLAY

SCHEMAIIC

SCHEMATIC

NOTE:

CONDITION

OF

OVEN

1

DOOR

CLOSED

2

CONVECTION

NOTE

:

CONDITION

OF

OVEN

1

DOOR

CLOSED

2

COOKING

TIME

PROGRAMMED

3

START

PAD

TOUCIHED

PAD

TOUCHED

3

DtSlRED

TEMPERATURE

PAD

TOUCHtD

4

START

PAD

TOUCHED

Fig

O-2

Oven

Schematic-Microwave

Cooking

Condition

Fig

O-3

Oven

Schematic-Convection

Cooking Condition

(High)

Fig

O-l

Oven

Schematic-OFF

Condition

3

‘II

HIGH VOI TAGE COMPONENTS

I

1

CN-

F

I

DM

:

DAMPER

SW1

:

UPPER

LATCH

FM

FAN

MOTOR

-

C

CONVECllON

CUT-OUT

9O”CfFM;

I

1~11~1

I

II

I

cG0u-r

CONTROL

PANEL

I

1

/I

1

I

1

TC?

THFRMAI

H

v

Recear

I

CN-8

I

PPL

1

P

BRN

:

-

QP

4

YLW

5-

6

PNK

7F

I

CM CONVECTION

MOTOR

III

ICOM

‘!

ily-

TC2

SW3.

MONITOR RESISlOR

SWITCH

-

I

CN-A

II

I

BLK

9.

I

(

1I

I

I1

8

WHT

7

6

I

-

ORG

5

-I

4

BRN

T----

2

POWER SUPPLY

RED

1

-

FUSE HOLDER

TTM

:

TURNTABLE

THERMAL

CUT~OUT

175°C

(OVEN)

NOTE

:

The marked

”

p

”

connector

IS

the

POSITIVE LOCK

‘d

Figure

S-l

Pictorial

Diagram

#

------.1-----

----:----..-.---.-----.-

.__.

_-

.

-

--m-7

--~---

.-.-.

.--

--~~~_~_

~

~--.-..---.-._

.,_..

Sharp R-7A53 User manual

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