LG MC-805GLR Service Manual

MICROWAVE/GRILL

CONVECTION

OVEN

SERVICE

MANUAL

MODEL

:

MC-805GLR

CAUTION

BEFORE

SERVICING

THE

UNIT,

READ

THE

SAFETY

PRECAUTIONS

IN

THIS

MANUAL.

This

device

istobe

serviced

onlybyproperly

qualified

service

personnel.

Consult

the

Service

Manual

for

proper

service

procedures

to

assure

continued

safety

operation

and

for

precautions

to

be

taken

to

avoid

possible

exposure

to

excessive

microwave

energy.

SAFETY

PRECAUTIONS

PRECAUTIONS

TO

BE

OBSERVED

BEFORE

AND

DURING

SERVICING

TO

AVOID

POSSIBLE

EXPOSURE

TO

EXCESSIVE

MICROWAVE

ENERGY

A)

Do

not

operate

or

allow

the

oven

to

be

operated

with

the

door

open.

B)

Make

the

following

safety

checks

on

all

ovens

to

be

serviced

before

activating

the

magnetron

or

other

microwave

source,

and

make

repairs

as

necessary;

(1)

Interlock

operation,

(2)

proper

door

closing,

(3)

seal

and

sealing

surfaces

(arcing,

wear,

and

other

damage),

(4)

damage

to

or

looseningofhinges

and

latches,

(5)

evidence

of

dropping

or

abuse.

C)

Before

turning

on

microwave

power

for

any

service

test

or

inspection

within

the

microwave

generating

compartments,

check

the

magnetron,

wave

guide

or

transmission

line,

and

cavity

for

proper

alignment,

integrity,

and

connections.

D)

Any

defective

or

misadjusted

components

in

the

interlock,

monitor,

door

seal,

and

microwave

generation

and

transmission

systems

shall

be

repaired,

replaced,oradjustedbyprocedures

described

in

this

manual

before

the

oven

is

released

to

the

owner.

E)

A

microwave

leakage

check

should

be

performed

on

each

oven

prior

to

release

to

the

owner.

CAUTION

MICROWAVE

RADIATION

DO

NOT

BECOME

EXPOSED

TO

RADIATION

FROM

THE

MICROWAVE

GENERATOR

OR

OTHER

PARTS

CONDUCTING

MICROWAVE

ENERGY.

TABLE

OF

CONTENTS

(Page)

SAFETY

PRECAUTIONS

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

Inside

front

cover

SPECIFICATIONS

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

CAUTIONS

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

2-1

INSTALLATIONS

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

3-1

OPERATING

INSTRUCTIONS

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

4-1

FEATURES

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

4-1

CONTROL

PANEL

.................................................................................................................................4-1

OPERATING

SEQUENCE

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

4-2

SCHEMATIC

DIAGRAM

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

4-3

CIRCUIT

DESCRIPTION

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

4-4

SERVICE

INFORMATION

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

5-1

TOOLS

AND

MEASURING

INSTRUMENTS

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

5-1

MICROWAVE

LEAKAGE

TEST

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

5-1

MEASUREMENT

OF

MICROWAVE

POWER

OUTPUT

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

5-3

DISASSEMBLY

AND

ADJUSTMENT

.....................................................................................................5-3

INTERLOCK

CONTINUITY

TEST

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

5-8

COMPONENT

TEST

PROCEDURE

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

5-9

TROUBLE

SHOOTING

GUIDE

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

5-14

EXPLODED

VIEW

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

6-1

REPLACEMENT

PARTS

LIST

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

7-1

SCHEMATIC

DIAGRAM

OF

P.C.B.

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

8-1

PRINTED

CIRCUIT

BOARD.................................................................................................................

8-2

PCB

PARTS

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

9-1

SPECIFICATIONS

1-1

ITEM

DESCRIPTION

Power

Requirement

230/240V

AC50Hz

Single

phase,

3

wire

grounded

Microwave

1350W

Grill

1350W

Convection

1450W

Combination

1450W

Power

Output

850W

full

microwave

power(IEC705)

Microwave

Frequency

2,450MHz

Magnetron

2M214

-

39F,

2M218J

Timer

99min.

50sec.

Outside

Dimensions

530(W)

X

322

X

500mm

Cavity

Dimensions

348(W)

X

232X374mm

Net

Weight

23.0kg

Shipping

weight

25.5kg

Control

Complement

Microwave

Power

for

Variable

Cooking

Power

level

HIGH...............................................Full

power

throughout

the

cooking

time(100%)

MED-HIGH

.....................................approx.

80%

of

Full

power

MEDIUM

.........................................approx.

60%

of

Full

power

DEFROST

......................................approx.

40%

of

Full

power

LOW

...............................................approx.

20%

of

Full

power

?

Convection

-

Max.

250°C

?

Grill

?

Combination

Name

plate

Location

Accessories

Owner's

manual

Glass

tray

Rotating

ring

Convection

rack

Grill

rack

Metal

tray

Rotisserie-Bar
Rotisserie-Handle

This

microwave

oven

is

designed

for

household

use

only.

It

is

not

recommended

for

commercial

purpose.

Back

Side

?

DO

NOT

operate

on

a

2-wire

extension

cord

during

repair

and

use.

?

NEVER

TOUCH

any

oven

components

or

wiring

during

operation

.

?

BEFORE

TOUCHING

any

parts

of

the

oven,

always

remove

the

power

plug

from

the

outlet.

?

For

about

30

seconds

after

the

oven

stop,

an

electric

charge

remains

on

the

high

voltage

capacitor.

When

replacingorchecking,

you

must

discharge

the

capacitor

by

shorting

across

the

two

terminals

with

an

insulated

screwdriver.

?

Remove

your

watches

whenever

working

close

to

or

replacing

the

Magnetron.

?

NEVER

operate

the

oven

with

no

load.

?

NEVER

damage

the

door

seal

or

front

plate

of

the

oven

cavity.

?

NEVER

put

iron

toolsonthe

magnetron.

?

NEVER

put

anything

into

the

latch

hole

and

the

interlock

switches

area.

?

Proper

operation

of

the

microwave

oven

requires

that

the

magnetron

be

assembled

to

the

waveguide

and

cavity.

Never

operate

the

magnetron

unlessitis

properly

installed.

?

Be

sure

that

the

magnetron

gasket

is

properly

installed

around

the

dome

of

the

tube

whenever

installing

the

magnetron

.

2-1

CAUTIONS

Unlike

other

appliances,

the

microwave

oven

is

high-voltage

and

high-current

appliance.

Though

it

is

free

from

danger

in

ordinary

use,

extreme

care

should

be

taken

during

repair.

MICROWAVE

RADIATION

Personnel

should

not

be

exposed

to

the

microwave

energy

which

may

radiate

from

the

magnetron

or

other

microwave

generating

device

if

it

is

improperly

used

or

connected.

All

input

and

output

microwave

connections,

waveguide,flange

and

gasket

must

be

secure

never

operate

the

device

withoutamicrowave

energy

absorbing

load

attached.

Never

look

into

an

open

waveguide

or

antenna

while

the

device

is

energized.

ANTENNA

GASKET

FILAMENT

TERMINAL

COOLING

FIN

MAGNETRON
CHASSIS
GROUND

THE

OVEN

IS

TO

BE

SERVICED

ONLY

BY

PROPERLY

QUALIFIED

SERVICE

PERSONNEL.

MAGNETRON

Installing

microwave

oven

1.

Empty

the

microwave

oven

and

clean

inside

it

with

a

soft,

damp

cloth.

Check

for

damage

such

as

misaligned

door,

damage

around

the

doorordents

inside

the

cavity

or

on

the

exterior.

2.

Put

the

oven

on

a

counter,

table

or

shelf

that

is

strong

enough

to

hold

the

oven,

food

and

utensils

you

put

in

it.

(The

control

panel

sideofthe

oven

is

the

heavy

side.

Use

care

when

handling.)

3.

Do

not

block

the

vent

and

the

air

intake

openings.

Blocking

vent

or

air

intake

openings

can

cause

damage

to

the

oven

and

poor

cooking

results.

Make

sure

the

microwave

oven

legs

are

in

place

to

ensure

proper

air

flow.

4.

The

oven

should

not

be

installed

in

any

area

where

heat

and

steam

are

generated,

because

they

may

damage

the

electronic

or

mechanical

parts

of

the
unit.
Do

not

install

the

oven

next

to

a

conventional

surface

unitoraboveaconventional

wall

oven.

5.

Use

the

microwave

oven

in

an

ambient

temperature

of

less

than

104°F

(40°C).

6.

Place

the

microwave

oven

on

a

sturdy

and

flat

surface,

at

least

10cm(4

inches)

from

the

wall.

7.

Place

the

microwave

oven

as

far

away

as

possible

from

TV,

RADIO,

COMPUTER

etc,

to

prevent

interference.

8.

This

oven

must

be

plugged

intoa15A

outlet.

9.

Do

not

touch

the

front

glass

during

or

after

cooking

of

the

Grill,

Convection

and

Combination

mode.

This

glass

is

very

hot

during

heater

operating.

10.

Do

not

operate

oven

at

microwave

and

combination

mode

with

the

Convection

rack

or

Grill

rack

placed

in

the

cavity

when

the

oven

is

empty.

Earthing

Instructions

This

microwave

oven

is

designed

to

be

used

in

a

fully

earthed

condition.

It

is

imperative,

therefore,

to

make

sure

it

is

properly

earthed

before

servicing.

WARNING-
THIS

APPLIANCE

MUST

BE

EARTHED

IMPORTANT

As

the

colours

of

the

wiresinthe

mains

leadofthis

appliance

may

not

correspond

with

the

coloured

markings

identifying

the

terminals

in

your

plug,

proceed

as

follows.

The

wire

which

is

coloured

green-and-yellow

must

be

connected

to

the

terminalinthe

plug

which

is

marked

with

the

letter

E

or

by

the

earth

symbol

( )

or

coloured

green

or

green-and

yellow.

The

wire

which

is

coloured

blue

must

be

connected

to

the

terminalinthe

plug

whichismarked

with

the

letter

N

or

coloured

black.

The

wire

which

is

coloured

brown

must

be

connected

to

the

terminalinthe

plug

whichismarked

with

the

letter

L

or

coloured

red.

*

Power

cord

type:

"Y"

Type

3-1

INSTALLATIONS

BEFORE

YOU

BEGIN,

READ

THE

FOLLOWING

INSTRUCTIONS

COMPLETELY

AND

CAREFULLY.

The

wiresinthis

mains

lead

are

coloured

in

accordance

with

the

following

code:

Green-and-yellow:

Earth

Blue:

Neutral

Brown:

Live

OPERATING

INSTRUCTIONS

4-1

1.

Grill:

To

select

grill

cooking.

2.

MICRO

POWER:

To

select

micro

power

cooking

and

cooking

power

levels.

3.

AUTO

COOK:

To

select

auto

cook.

4.

CLOCK:

To

set

the

time

of

day.

5.

AUTO

ROAST

6.

TIME:

To

set

cooking

times.

7.

DISPLAY

WINDOW:

Used

to

show

Time

of

day,

Cooking

of

day,

Cooking

power

level,

Cooking

category.

8.

COMBINATION:

To

select

combination

cooking.

9.

CONVECTION:

To

select

convection

cooking.

10.

AUTO

WEIGHT

DEFROST:

To

select

auto

weight

defrost.

11.

WEIGHT:

To

set

weight

of

food

auto

weight

defrost.

12.

LESS/MORE:

To

select

convection

temperature,

and

change

auto

cook

time

and

auto

reheat

time.

13.

STOP/CLEAR,

CHILD

LOCK:

Stops

the

oven

and

clear

all

entries

except

the

time

of

day.

14.

START/QUICK

START:

To

quickly

set

the

cooking

time

directly.

Control

panel

Glass

turntable

Rotating

ring

Shaft

Metal

tray

Convection

rack

Grill

rack

Oven

front

face

Window

door

screen

Door

seal

Latch

ROTISSERIE-BAR

ROTISSERIE-HANDLE

2

8

9

10

11

12

13

14

7

1

4

5

6

3

10min1min

10sec

Stop/Clear

Quick

Star

1.

Meat

2.

Poultr

1.

Jacket

Potato

2.

Rice/Pasta

1.

Roast

Beef

2.

Roast

Pork

3.

Whole

Chicken

3.

Fresh

Vegetables

2.

Frozen

Vegetables

1.

Fish

2.

Bread

Auto

Cook

Micro

Grill

Conv

Combi

0.1kg

1.0kg

More

Features

Control

Panel

The

following

is

a

description

of

component

functions

during

oven

operation.

1.

Setting

the

clock

2.

Cooking(Microwave

power)

3.

Multi

stage

cooking

4.

Grill

cooking

5.

Convection

cooking

To

pre-heat

To

cook

6.

Combination

cooking

7.

Auto

weight

defrost

8.

Auto

roast

9.

Auto

cook

10.

Child

lock

This

oven

has

a

CHILD

LOCK

feature.

To

Set

CHILD

LOCK

To

Cancel

CHILD

LOCK

11.

Quick

start

12.

More

and

Less

Operating

Sequence

4-2

Plug

the

power

cord

into

an

electric

outlet

Clock

Set

the

correct

minute

Clock

Set

the

correct

hour

Stop

Stop

Desired

power

level

Desired

cooking

time

Start

Stop

Desired

power

level

Desired

cooking

time

Desired

cooking

time

Start

Stop

Stop

(Touch

and

HOLD)

Stop

Stop

(Touch

and

HOLD)

Stop

Start

Stop

More

Less

Programme

desired

auto

cook

Stop

Desired

defrost

category

Desired

cooking

weight

Start

Stop

Desired

auto

roast

category

Desired

cooking

weight

Start

Stop

Desired

auto

cook

category

Desired

cooking

weight

Start

Desired

power

level

(20%,

40%

or

60%)

Desired

cooking

time

Start

Stop

Desired

convection

temp(40oC,

100oC~250oC)

Start

Stop

Desired

convection

temp

(40oC,

100oC~250oC)

Start

Combination

Desired

convection

temp(100oC~250oC)

Grill

Desired

power

level

Desired

power

level

Desired

cooking

time

Start

Desired

cooking

time

Grill

or

convection

or

combination

Desired

cooking

time

Stage

1

OR

Stage

2

SCHEMATIC

DIAGRAM

4-3

?

As

the

door

is

closed,

the

contact

of

MONITOR

SWITCH

opens.

This

switch

creates

the

short

circuit

to

blow

10

A

fuse

during

operation

under

abnormal

condition.(ie,

should

the

contacts

of

primary

fail

to

open

the

circuit)

?

The

latches

are

secured

by

latch

board.

The

oven

light

turns

on

while

the

oven

is

in

operation.

WHEN

COOKING

POWER

LEVEL

AND

COOKING

TIME

ARE

SET

?

The

contacts

of

the

primary

switch

and

the

secondary

switch

close

the

circuit.

?

230V

A.C.

is

applied

to

the

high

voltage

transformer

through

power

control

switch

as

shown

by

the

solid

line.

?

Turntable

and

circulation

motor

rotate.

?

The

fan

motor

rotates

and

cools

the

magnetron

by

blowing

the

air

(coming

from

the

intake

on

the

backplate)

over

the

magnetron.

?

The

airisalso

directed

into

the

oven

to

exhaust

the

vapor

in

the

oven

through

the

base

plate

and

back

plate.

?

3.5V

A.C.

is

generated

from

the

filament

winding

of

the

high

voltage

transformer.

This

3.5V

is

applied

to

the

magnetron

to

heat

the

magnetron

filament

through

two

noise

preventing

choke

coils.

A

high

voltage

of

approximately

2100V

A.C.

is

generated

in

the

secondary

of

the

high

voltage

transformer

which

is

increased

by

the

actionofthe

diode

and

charging

of

the

high

voltage

capacitor.

The

negative

D.C.

voltage

is

then

applied

to

the

filament

of

the

magnetron.

WHEN

THE

DOOR

IS

OPEN

DURING

COOKING

?

Both

primary

switch

and

secondary

switch

open

to

cut

off

the

primary

winding

voltage

to

the

high

voltage

transformer

to

stop

microwave

oscillation.

?

Turntable

and

fan

motor

stop.

?

As

the

door

is

opened,

if

the

contact

of

primary

switch

and

relay

2

and/or

secondary

switch

fail

to

open,

the

10A

fuse

opens

duetothe

large

current

surge

caused

by

the

monitor

switch

activation

which

in

turn

stops

magnetron,

oscillation.

WHEN

TOUCHING

THE

START

KEY

WITH

THE

CONVECTION/GRILL

COOKING

FUNCTION

SELECTED.

?

The

contacts

of

the

primary

switch

and

the

secondary

switch

close

the

circuit.

?

230V

A.C.

is

applied

to

the

grill

heater

through

grill

thermostat

as

shown

by

the

solid

line.

?

Turntable

rotate.

?

The

fan

motor

and

circulation

motor

rotate.

?

The

airisalso

directed

into

the

oven

to

exhaust

the

vapor

in

the

oven

through

the

base

plate

and

back

plate.

Circuit

Description

4-4

FUSE

10A

PRIMARY

SWITCH

N

L

RELAY

2

H.V.T

MONITOR

SWITCH

FUSE

10A

PRIMARY

SWITCH

N

L

RELAY

2

H.V.T

MONITOR

SWITCH

CONVECTION

HEATER

RELAY

4

L

N

E

N

L

G-Y

RELAY

3

GRILL

HEATER

OVEN

THERMOSTAT

L

N

E

N

L

G-Y

RELAY

3

GRILL

HEATER

OVEN

THERMOSTAT

NECESSARY

TOOLS

Tools

normally

used

for

TV

servicing

are

sufficient.

Standard

tools

are

listed

below.

?

Diagonal

pliers

?

Long

nose

pliers

?

Cross

head

screwdriver

?

Wrench

(size5mm)

?

Nutdriver

(size5mm)

?

Adjustable

wrench

?

Soldering

iron

?

Solder

?

Vinyl

insulation

tape

?

Polishing

cloth

CAUTIONS

?

Be

sure

to

checkamicrowave

emission

prior

to

servicing

the

oven

if

the

oven

is

operative

prior

to

servicing.

?

If

the

oven

operates

with

door

open,

the

service

personnel

should;

---Tell

the

user

not

to

operate

the

oven

?

The

service

personnel

should

check

all

surface

and

vent

openings

for

microwave

emission

testing.

?

Check

for

microwave

energy

leakage

after

every

servicing.

The

power

density

of

the

microwave

radiation

leakage

emitted

by

the

microwave

oven

should

not

exceed

4

mW/cm2.

And

always

start

measuring

of

an

unknown

field

to

assure

safety

for

operating

personnel

from

radiation

leakage.

NOTE:

The

standard

is5mW/cm2

whileinthe

customer's

home.

4

mW/cm2

stated

here

is

manufacturer's

own

voluntary

standard

for

units

in

customer's

home.

EQUIPMENT

?

Microwave

Survey

Meter

?

600cc

glass

beaker

?

Glass

thermometer

100°C

NECESSARY

MEASURING

INSTRUMENTS

?

TESTER

(VOLTS-DC,

AC,

Multmeter)

?

Microwave

survey

meter

---Holaday

H1-1500,

Hi-1501

---Narda

8100,

8200

?

Inch

scale

?

600

cc

non

conductive

material

beaker

(glass

or

plastic),

inside

diameter:

approx.

8.5cm

(31/2

in.)

?

Cylindrical

and

made

of

borosilicate

glass

vessel

max.

thickness:

3mm

outside

diameter:

approx.

190mm

height:

approx.

90mm

?

Glass

thermometer:

100°C

or

212°F

(1

deg

scale)

MEASURING

MICROWAVE

ENERGY

LEAKAGE

?

Pour

275

±

15cc

of

20°C±5°C

water

in

a

beaker

which

is

graduated

to

600

cc,

and

place

the

beaker

on

the

center

of

the

turntable.

?

Set

the

energy

leakage

monitor

to

2,450

MHz

and

use

it

following

the

manufacturer's

recommended

test

procedure

to

assure

correct

result.

?

When

measuring

the

leakage,

always

use

the2inch

(5cm)

spacer

supplied

with

the

probe.

?

Operate

the

oven

at

its

maximum

output.

?

Measure

the

microwave

radiation

using

and

electromagnetic

radiation

monitor

by

holding

the

probe

perpendicular

to

the

surface

being

measured.

Tools

and

Measuring

Instruments

5-1

Microwave

Leakage

Test

SERVICE

INFORMATION

Move

probe

along

shaded

area.

Probe

scanning

speed;

Less

than

2.5

cm/sec

MEASUREMENT

WITH

THE

OUTER

CASE

REMOVED

?

When

you

replace

the

magnetron,

measure

microwave

energy

leakage

before

the

out

case

is

installed

and

after

all

necessary

components

are

replaced

or

adjusted.

Special

care

should

be

taken

in

measuring

the

following

parts.

(Shaded

area

of

below

Fig.)

---

Around

the

magnetron

---

The

waveguide

MEASUREMENT

WITH

A

FULLY

ASSEMBLED

OVEN

?

After

all

components,

including

the

outer

case,

are

fully

assembled,

measure

for

microwave

energy

leakage

around

the

door

viewing

window,

the

exhaust

opening

and

air

inlet

openings.

?

Microwave

energy

leakage

must

not

exceed

the

values

prescribed

below.

NOTES:

Leakage

with

the

outer

case

removed

-

less

than

5

mW/cm2.

Leakage

for

a

fully

assembled

oven

("Before

the

latch

switch

(primary)

is

interrupted")

with

the

door

in

a

slightly

opened

position

-

less

than4mW/cm2.

NOTES

WHEN

MEASURING

?

Do

not

exceed

meter

full

scale

deflection.

?

The

test

probe

must

be

removed

no

faster

than,

1

inch/sec

(2.5

cm/sec)

along

the

shaded

area,

otherwise

a

false

reading

may

result.

?

The

test

probe

must

be

held

with

the

grip

portion

of

the

handle.

A

false

reading

may

resultifthe

operator's

hand

is

between

the

handle

and

the

probe.

?

When

testing

nearacorner

of

the

door,

keep

the

probe

perpendicular

to

the

surface

making

sure

the

probe

horizontally

along

the

oven

surface,

this

may

possibly

cause

probe

damage.

RECORD

KEEPING

AND

NOTIFICATION

AFTER

MEASUREMENT

?

After

adjustment

and

repair

of

any

microwave

energy

interruption

or

microwave

energy

blocking

device,

record

the

measured

values

for

future

reference.

Also

enter

the

information

on

the

service

invoice.

?

Should

the

microwave

energy

leakage

not

be

more

than4mW/cm2

after

determining

that

all

parts

are

in

good

condition,

functioning

properly

and

genuine

replacement

parts

which

are

listedinthis

manual

have

been

used.

?

At

least

once

a

year,

have

the

electromagnetic

energy

leakage

monitor

checked

for

calibration

by

its

manufacture.

5-2

WARNING:

AVOID

CONTACTING

ANY

HIGH

VOLTAGE

PARTS