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SERVICE MANUAL Microwave Oven
Sio
EM870FS (Nevuealand)
Jan 221992
/
/
Product Code No.
432-328-51
Foreword
Read this manual carefully, especially precaution on microwave energy, and follow the procedure strictly. Careless servicing and
testing may expose yourself to the microwave energy leakage.
PRECAUTIONS
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EX-
CESSIVE MICROWAVE ENERGY
(a) Do not operate or allow the oven to be operated with the door open.
(b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source,
and make repairs as necessary:
(1) Interlock operation, (2) proper door closing,
(3) seal and sealing surfaces (arcing, wear, and other damage), (4)
damage to or loosening of hinges and latches, (5) evidence of dropping or abuse.
(cl Before turning on microwave power for any service test or inspection within the microwave generating compartnlents.
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 trans.
mission systems shall be repaired, replaced. or adjusted by procedures described in this manual before the oven is released
to the owner,
REFERENCE NO. WM-fMo 208
P .
,., ,
– TABLE OF CONTENTS -
Adjustment Procedures . . . . . . . . . . . . . . . . . . . . . . 1
Automatic Reheat Operation . . . 0 . . 0 . . . . . . , 4-7
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . ...2
Test Procedures and Troubleshooting , . . . . . . . . . 8-14
Power Output Measurement . . . . . . . . . . . . . . . . . . . 2
Disassembly Instructions . . . . . . . . . . . . . . . . . .15-18
Precautions and Repair Service Tips . . . . . . . . . . . . . . 2
Exploded View and Parts List . . . . . . . . . . . . . . .19-24
Circuit Diagram . . . . . . . . . . . . . . . . . . . . . . . . ...3
Overall Circuit Diagram . . . . . . . . . . . . . . . . . . . 25
CAUTION
MICROWAVE RADIATION
PERSONNEL SHOULD NOT BE EXPOSED TO THE
MICROWAVE ENERGY WHICH MAY RADIATE
FROM THE MAGNETRON OR OTHER MICRO-
WAVE GENERATING DEVICE IF IT IS impro-
perly USED OR CONNECTED. ALL INPUT AND
OUTPUT MICROWAVE CONNECTIONS, WAVE-
GUIDES FLANGES, AND GASKETS MUST BE
sECURE. NEVER OPERATE THE DEVICE WITH-
OUT A MICROWAVE ENERGY ABSORBING
LOAD ATTACHED. NEVER LOOK INTO AN
OPEN WAVEGUIDE OR ANTENNA WHILE THE
DEVICE IS ENERGIZED.
1. ADJUSTMENT PROCEDURES
TO AVOID POSSIBLE EXPOSURE TO MICROWAVE
ENERGY LEAKAGE, THE FOLLOWING ADJUSTM-
ENTS OF THE INTERLOCK SWITCHES SHOULD
BE MADE ONLY BY AUTHORIZED SERVICE
PERSONNEL.
PRIMARY
INTERLOCK SWITCH,
INTERLOCK
MONITOR SWITCH AND DOOR SENSING SWITCH
ADJUSTMENT
(Figure 1)
[1)
(2)
\
(3)
(4)
(5)
(6)
Loosen 2 screws securing the lever stopper.
Adjust the lever stopper position so that it is pushed
forward and pull backward until thele is about zero
gap between the latch lever and the switch body
On the primary interlock switch and at the same
time there is about zero gap between the door latch
and the switch body on the door sensing switch
when the door latch is securely locked.
Tighten the lever stopper screws securely.
Make sure the interlock monitor switch closes after
the primary interlock switch opens when the door
is opened very slowly, according to “CHECKOUT
PROCEDURE FOR SWITCHES” on page 6.
Make sure the interlock monitor switch opens
before the primary interlock switch closes when the
door is closed very slowly, according to “CHECK-
OUT PROCEDURE FOR SWITCHES” on page 6.
Make sure the microwave energy leakage is below
the limit of the regulation (5 mW/cm2 ) when
measured with a detector.
(AI{ service adjustments must be made for minimum
micro wave energy leakage readings. )
NOTE:
-1
/
,rews
/
=--
--
If the interlock monitor circuit operates
arsd at the same time the fuse blows with
the door opened, be sure to replace the
control circuit board because relay 2 on
the control circuit board, the door sensing
switch and the electric circuit related on
the door sensing switch, which act as
Secondary Interlock Switch.
Door
Latch
‘1 /
!-ever Stopper
F
j’”/
x
Door
Sensing
\
, Switch
‘w
~= Swich
Interlock
Monitor
/)
Latch Lever
Primary
Interlock
Switch
Figure 1
–l–
2. SPECIFICATIONS
Rated Power Consumption . . .
Microwave Output . . . . . . .
Frequency . . . . . . . . . . . . . .
Power Supply . . . . . . . . . . .
Rated Current . . . . . . . . . . .
Safety Devices . . . . . . . . . . .
Timer . . . . . . . . . . . . . . . . .
Overall Dimensions . . . . . . . .
Oven Cavity Size . . . . . . . . .
Turn Table Diameter . . . . . . .
Effective Capacity of
Oven Cavity . . . . . . . . . . .
Net Weight . . . . . . . . . . . . .
1400W
700W
(Adjustable 155W through
700W)
2,450 MHz f 50 MHz
230- 240V50HZ
6.0 Amp.
Thermal Protector, Open
at 135°C for Magnetron
Fuse (Cartridge Type 8A)
Primary Interlock Switch
Door Sensing Switch and
Relay 2
Interlock Monitor Switch
Electronic Digital, up to
99 min. 99 sec.
550(W) x 453(D) x 309(H) mm
375(W)X 404(D) x 237(D) mm
360 mm
31 liter
Approx. 20 kg
3. POWER OUTPUT MEASUREMENT
(1) Fill two beakers (glass or plastic) with each one liter
of taP water (about 20° C) and measure the water
temperature. (Use a thermometer with a 1/10
degree gauge. )
(2) Place the beakers side by side in the center of the
glass tray.
(3) Close the door, set the “TIME” for two minutes.
(.,2 O(y?
in the display window. ) Touch the
“START” key and heat the water exactlv for two
minutes.
(4) Take the beakers out, immediately stir the water
and measure the water temperature respectively.
(5) Calculate the temperature rise of water in each
beaker. Then calculate the average value of two
temperature rises.
Output power can be calculated by the equation;
Power output (W) = 70 x At
Where At is an average temperature rise in degrees
Centigrade.
(6) Output shall be in the following range:
Average temperature rise Power output
Minimum
9.O”C
630W
Maximum
11.5°c 805W
(7) Power output is affected by the line voltage under
load. For correct power output measurement, the
line voltage under load must be 240t 1 volts.
4. PRECAUTIONS
PRELIMINARY
A. SINCE NEARLY
AND REPAIR SERVICE TIPS
4,OOO VOLTS EXISTS IN SOME
CIRCUITS OF THIS MICROWAVE OVEN, REPAIRs
SHOULD BE CARRIED OUT WITH GREAT CARE.
B. TO AVOID POSSIBLE EXPOSURE TO MlCROWAVE
ENERGY LEAKAGE,
THE FOLLOWING PRE-
CAUTIONS MUST BE TAKEN BEFORE SERVICING.
(1) Before the power is applied:
(a) Open and close door serveral times to make sure the
primary interlock switch, the interlock monitor
switch and the door sensing switch operate proper-
ly. (Listen for the clicking sound from the switches. )
Make sure the interlock monitor switch closes after
the primary interlock switch is opens when the door
is opened.
(Seepages 1 and 6)
(b) Make sure the perforated screen and the choke di-
electric of the door are correctly mounted.
(2)
(a)
(b)
(3)
(a)
(b)
(c)
(d)
(e)
(f)
(4)
(a)
(b)
(c)
(d)
(e)
The
After the power IS applied:
Open and close the door to see if the interlock
mechanism operates properly.
Check microwave energy leakage with a leakage
detector and confirm the energy leakage is below 5
mW/cm2.
Do not operate the unit until it is completely re-
paired, if any of the following conditions exists.
Door does not close firmly against the cavity front.
The hinge is broken.
The choke dielectric or the door seal is damaged.
The door is bent or warped, or there is any other
visible damage to the oven that may cause micro-
wave energy leakage.
NOTE: Always keep the seal clean.
Make sure that there are no defective parts in the
interlock mechanism.
Make sure that there are no defective parts in we
microwave generating and transmission assembly.
(especially waveguide)
The following items should be checked after the
unit is repaired:
The interlock monitor switch is connected correctly
and firmly.
The magnetron gasket on the magnetron is properly
positioned.
Waveguide and oven cavity are intact (no leakage of
microwave energy).
The door can be properly closed and the safety
switches work properly.
The oven must be stopped when the door is opened
or the time is up.
oven must not be operated with any of the above
components removed or bypassed.
–2–
,,!
5. CIRCUIT DIAGRAM
PoWER SUPPLY
9
=
-$l!
-1 [-
FUSE I
I
I
8A(T) I
L–=–-J 1
I
I
i
7t5”c
I
I CAVITY LAMP
w
BK
f
I I
I
I
w
THERMAL PROTECTOR
5
FOR MAGNETRON OPEN
J“ { ‘ C*’
GEAR MOTOR
GM
BK
\
r-
W
~.__——-—
\ ~~NNECTOR
.—-— —
——-
1
2
@ LwTr’&k?K
\
SWITCH
@ !’fwwci
o
SWITCH
NC
4+
BLOWER MOTOR
CONNECTOR
HIGH VOLTAGE TRANSFORMER
f————-—— —- —____ __m
S201
w i
A.+
i
BK
-—— . ..
I
[
J--
I
El
I
I
i
:OM
\
NO
.)
RELAY 2 (
I
I 3
I
CONNECTOR
L —-—— ——
- -i
——- —
——
< )-
J
I
5
S102
. I
i
RELAY 1
●
R
STEP 00WN
FUSE DIOOE
I
TRANSFORMER
~——–_T
I
10
I DOOR
‘ c.
, SENSING
DIODE
I
0.97MF0
I
CONTROL
I
SWITCH
I
CIRCUIT
/
BOARD
I
I
10MEG.OHM
I
/
I
I
,\ c
CONNECTOR
I
I
J
Slol
I
I
1-
L ———— -
J
-—— ———— ———— ——— —
1
BK
I
WIRING COLOR
Notas: Th.sign @ - Th. parts markad with ❑ar. s.rw,i.d
high voltage which is ●xcaadad 250V.
BK :
BLACK
BR :
BROWN
Tha
sign @ -
The Patts markad with @ hava special
w
: WHITE
GY :
GRAY
charactcristia important for microwav-
o
: ORANGE
BL :
BLUE
Ioakage. When replacing sny of thase parts
R
: RED
use
only manufactur,’s spacifiad parts.
Figure 2
–3-
6. AUTOMATIC REHEAT OPERATION
Automatic reheat is controlled by a humidity sensor.
Power level, reheating time, doneness temperature and
quantity of food donot need to beset.
The humidity sensor detects moisture asit escapes from
the food being reheated.
The microprocessor on the circuit board receives the
signals from the sensor and controls the power level and
the reheatng time automatically.
A. HOW THE HUMIDITY SENSOR WORKS FOR “AUTO-
MATIC REHEAT”
The humidity sensor is located on the left rear of
Oven Cavitv. (Figure 5)
This sensor detects an amount of moisture as it escapes
from the food and the amount of moisture is closely
related to the doneness of the food being reheated.
The sensor is composed of two thermistors. One is
sealed in a dry air compartment and the other is in an
open compartment. (Figure 4)
The both thermistors are heated by themselves at about
200°C when the oven is plugged in. The thermistor in
a dry air compartment is cooled by the influence of air
temperature and the thermistor in an open compartment
is cooled by not only the air temperature but also evapo-
ration of the moisture in the air around the sensor.
If the sensor is in a dry air, the both thermistors in the
sensor have the same resistance value, regardless of the
air temperature.
But if it is in a moist air, the thermistor in an open com-
partment will be cooled more by evaporation of the
moisture and the resistance value will increase, compared
with the thermistor in a dry air compartment.
This develops a difference between both thermistors in
resistance value.
The sensor sends that information to the micro com-
puter, which calculates and automatically adjusts the
power level and remaining operating time.
J=ii3=
-o---
==0:=
-=- _
-0.
Q
Outside of
Humidity Sensor
Figure 3
Thermistor Thermistor
\
Moist Air
/
Dry Air-
Open’
Compartment
Compartment
Inside of
Humidity Sensor
Figure 4
–4–
.
B . EASY USE CHART
2 DONENESS KEYS
1. Touch CLEAR
2. Touch a Categcxy Key
REHEAT l(for A 1) mREHEAT2(fof A2)
3. Touch a Dcneness Key
LOW M HIGH if desired
4. Touch START
Note: About 5minutes after the oven is first Plugg-
ed for stable operation of a humidity sensor.
Use ‘Automatic Reheat- after waiting 5minutes.
-CATEGORY
8 AUTOMATIC
SENSOR COOKING COURSES ‘
a) 2 COURSES OF AUTOMATIC
SENSOR REHEA -
-.
TING fcr heating pecooked focds.
~
REHEAT 1:Preccoked Rcorn Temperature
and Refrigerated Temperature Food..
REHEAT 2:Preccmked Frozen Dense Fo-
A2 ~s
b) 6 COURSES OF AUTOMATIC SENSOR COOKl-
NG for cooking fresh or frozen fcxxk.
couRsE# lFOOD CATEGORy ]COURSE#l FOOD CATEGORY
The oven automatically sets to medium if no selec-
ticm is made.
If you prefer to have your food reheated or cooked
moore or less than the preset medium setting, touch
cne of the two DONENESS keys befcx tcuching START.
When a different doneness is chosen from the pres-
et medium (2), it is confirmed with a number(l to 3)
in the course indication display.
The indication ‘Al -2-for-REHEAT 1- changes as a
different doneness is entered.
Dcmeness Setting
Ccurse Indication
LOW -Al-l-
medium
‘Al -2-
(preset position)
HIGH
‘Al -3-
The indication
‘C4-2”for-Rl CE- changes as a dif -
ferent doneness is entered.
1
Doneness Setting
Course Indication
t
LOW
-C4-1 “
medium
‘C4-2-
( preset position)
HIGH
“c4-3-
Imml
–5–
C. POINT TO REMEMBER
● Before using Auhxnatic Sensw Programs...
The oven should be plugged into power supply for
more than five minutes.
Wipe off any noticeable moisture or spillovers fr-
om the wen.
If the inside of the oven is very warm, wait until
it cools down.
Automatic Sensor may not operate properly if the
room temperature is higher than 95”F(35°C ).
● Do not touch STOP/CLEAR, once cooking starts.
This will void the Automatic.
Sensor program and the food will need to be finis-
hed by using regular micrcwave operation.
● Make sure to use the correct food category or reh-
eat course for the food that is to be reheated or
cooked.
. The oven door must remain closed while display sh-
ows course indication (- C1-2-, -C2-2., -A1 -2-
and so cm) unless
‘PAUSE-
appears in the display.
If the door is opened, -Err- (error) will flash in
the display. This indicates the operation must be r-
reprogrammed into the oven. NOTE: The oven door may
be opened when time countdown appears in the disp-
lay.
. Automatic sensor cannot be used with other functi-
ons such as Time, temperature probe, Auto Defrost.
When the Temperature Probe is plugged in and Auto-
matic Sensor Cooking is started, the word ‘Probe”
will flash and the oven will not work.
–6–
7. INTERNAL AIR FLOW
The blower motor always runs during cooking or reheating. The air from the blower divides into two ways as shown in
Figure 5. This prevents the sensor from being affected by the warm air which has no relation with the doneness of food
being reheated.
(1) Air flow for rotating the stirrer fan
Air flow is shown by solid arrows in Figure 5.
The air from the blower cools the magnetron and
becomes warm. The warm air goes into a stirrer
compartment to rotate the stirrer fan.
(2) Air flow for carrying the moisture escaping from
food to the sensor
Air flow is shown by shaded arrows in Figure 5.
The air from the blower motor goes into cavity
inside and carries the moisture escaping from the
food being reheated to the sensor.
CAUTIONS:
- The stirrer cover inside of the oven cavity acts
asan air
partition between the air for rotating the stirrer fan and
the
air for carrying the moisture escaping from food to
the sensor. The stirrer cover must be secured p,”operly.
—
The oven cabinet (outer wrap) acts
asan air wide. The
stirrer fan may not rotate properly and the sensor may
not detect the moisture escaping from the food properly
while the oven cabinet is removed.
Air
Humidity Sensor
Exhaust
/
Figure
5
–7–
Air
Intake
I Blower
?\, ,
R
Filament Windings
8 .TEST PROCEDURES AND TROUBLESHOOTING
/“1
rc””’’””~
DISCONNECT THE POWER SUPPLY CORD
FROM THE WALL OUTLET WHENEVER RE-
MOVING THE CABINET FROM THE UNiT, PRO-
CEED WITH THE TESTS ONLY AFTER DIS-
CHARGING THE HIGH VOLTAGE CAPACITOR
AND REMOVING THE LEAD WIRES FROM THE
PRIMARY WINDING OF THE HIGH VOLTAGE
TRANSFORMER. (SEE FIGuRE 6 )
A. TEST PROCEDURES
COMPONENT
MAGNETRON
HIGH-VOLTAGE
TRANSFORMER
s
CHECKOUT PROCEDURE
1) Check for resistance: Across the filament
terminals of the magnetron with an ohmm-
eter on R x i scale.
1 r
ohm-meter
w
2) Check for resistance: Between each fila-
ment terminal of the magnetron and the
chassis ground with an ohm-meter on
highest scale.
ohm-meter
G
Q
Figure
8
1) Measure the resistance:
With an ohm-meter on R x 1 scale.
a. Primary winding;
b. Filament winding;
c. Secondary winding;
2) Measure the resistance:
With an ohm-meter on highest scale.
a. Primary winding to ground;
b.
ohm-
Note:
measured point.
Figure 6
RESULT
Normal reading:
Less than 1 ohm.
Normal reading:
Infinite ohms.
Normal readings:
Approximately 1.4 ohms.
Less than 1 ohm.
Approximately 87 ohms.
Normal readings:
Infinite ohms.
Infinite ohms.
–8–
‘COMPONENT
HIGH-VOLTAGE
CAPACITOR
including
BLEEDER
RESISTOR
HIGH-VOLTAGE
DIODE
t-
FUSE DIODE
CONTROL
CIRCUIT BOARD
CHECKOUT PROCEDURE
Measure theresistance: Across two terminals
with an ohm-meteron highest scale.
Figure 10
Measure the resistance. Across two terminals
with an ohm-meter on highest scale.
ohm-meter
n
a
b
Figure 11
Measure the resistance: Across two terminals
with an ohm-meter on highest scale.
Ohm-meter
n
Measure the voltage: Between test points
TP-1, TP-2, or TP.3 and ground between TP-
4, TP-5 and TP-6 (See control circuit bo-
ard on page 24)
NOTE
Proceed with the check of the step-down
transformer, to see if any one of the measur-
ed values is different from the specified
values.
RESULT
Normal reading:
Momentarily indicates several ohms, and
gradually returns to 10 meg-ohms.
Abnormal reading:
Indicates continuity or 10 megohms from
the beginning.
Normal reading:
Indicates about the middle position in one
direction (forward direction) and infinite
ohms in the reverse direction, using meter
which is provided with a 9-volt battery.
NOTE
– Some digital meter may show over even
in a forward direction because low measur-
ing voltage of meter does not allow the
meter current to pass through the high
voltage diode.
Abnormal reading:
Indicates continuity or infinite ohms in
both
directions.
Normal reading:
Indicates infinite ohms in both directions.
Abnormal reading:
Indicates continuity in both directions or
continuity in one direction and infinite
ohms in reversed direction.
Test
Point
‘P-4’ TP-6
‘p” ‘ ‘P-2 ‘P.3
TP-5
–5V –12V –30V
2.OV +1.5V
Voltage
Dc DC Dc
Ac Dc
–9-
-.
,’
.
COMPONENT
TOUCH KEY
BOARD
CHECKOUT PROCEDURE
Measure the resistance between terminals of
FPC connector after removing i\ from SIO1.
(Figure 13)
NOTE
When reconnecting the FPC connector,
make sure the holes on the connector are
properiy inserted in hooks of the
fastener in S101.
MATRIX CIRCUIT FOR
TOUCH KEY BOARD
FPC CONNECTOR
plastic
---- ——
—.. — —-——
———
——— .
-i
i
-1
I
I
I
I
I
I
I
I
RESULT
I
EEEaza
When checking “START” key, connect ohm-
meter as illustration below.
a
G3
ohm-meter
Top
\\-
F-/t---
TERMINALS OF FPC CONNECTOR
Figure 13
CHECKOUT PROCEDURE FOR SWITCHES
Disconnect the lead wires from the switches and check for the continuity of the switches connecting an ohmmeter to its termi.
nals.
1
SWITCHES
(See Figure
1 on page 1)
CHECKOUT PROCEDURES
DOOR OPEN
DOOR CLOSED I
Primary Interlock
Terminals “COM” and “NO”
Door Sensing
Q
@;
Interlock Monitor
Terminals “COM” and “NC”
I
a
@!
CAUTION: After checking the switches,
make
sure that the interlock monitor switch is ProPerl Y connec[ed according tO [h
s
CIRCUIT DIAGRAM on page 3.
:
m“
–lo–
,;
!:
B. TROUBLESHOOTING
,..,...
.
!. ...
. ,
.....1
,, ...
. .
...’.!
STEP
SEQUENCE
RESULT
1) PROBLEM
I
10 display or mis.display in
I
I
~edisplay window by touch,
I m
I
,1,
0 240
19
the keys.
@
I
t
@
I
t
J
a
o Vol
o–1
v
Check continuity. of
Replace it
i
Runs
thermal protector for
if necessary.
I
magnetron and AC Power
1
cord. If the fuse is below.
I
See “F. REMOVING
I
I
FUSE” on page 17.
I
1
Check 240 VAC power supply
i
through fuse (8A) and
t!wrnd pr9bxh2r fw
[
PROBLEM
.- ..= ..._
Magnetron,
.—...— ..
__ -.. ..- ... . . . . .. .. . .....=
----- ...
I
14?
1’
240 vOlt
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,,’
:
‘.
,,
,,
.:
,,
,.
,
,’.‘,
,,,
,;’,
,,
:.
‘.’.
,,
,
., -..
;
‘.*.’.
,,.
.
.
.,
:.’
,.
,>
.. .
,
,,
.,
,,:
b
I
Conlrol
circuit board
Check power supply voltage
on control circuit board.
(See page 9)
Touch key board
?
*
000
000
000
Each voltage
Check resistance of
OK
touch key board,
(See page 6)
1
@
l,’
I
‘@
I
Each resistance
Correct seating of
Normal control I
Runs
OK
connector S101 or
circuit board
I
I
replace control
I
circuit board.
I
I
I
r
I
@
000
000
000
I
I
Resistance
Replace touch key
Normal touch
I
I
Runs
incorrect
board,
key board
I
(ON or OFF)
I
I
I
I
@
I*”
‘@
I
I
Voltage
Replace control
Normal control ~
Runs
Incorrect
circuit board.
circuit board
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,.
.,
.
,.
.’,
,,
,:
.,
,,
.’,
.
.,,
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‘.
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,,.
. .. .
.:.
.
}..
., ..;.,,
‘,,
,.:,.
“.
,,,:.
,, :.
:,.;
9
CTcn RF~ll FNCF
RESULT
,,
‘,, .
,., ,
.,
.;.
.;
,,
,,, ,
.“,:
,,.,
,.:.
.. .
,.
,.
,.
.
.:. :
,’,’
,,.’...
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i,
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,,.
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h)
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oiLr
--------- --
2) PROBLEM
I
I
hoking operation will not
I
I
tart. I
CHECK: 1. Power Supply to Oven
I
a
2, Primary Interlock Switch
I
3 Thermal Protector for Magnetron
-a
I
I PROBLEM
3-a
lb
Contact
I
1
OK
I
I
i
Door sensing switch
1
Continuity
Checkcontact
I
D
I
o OK
of connector
-a—@-a
1~1,
●
S102.
I
Check continuity of con.
I
‘@
nector S102 between Pins
(0 W( DL) wilh tho door
Poor
Correct
Normal
I
cQntact
seating,
contact
closed after rerrtthrin~
connector S102 from
‘-’-” ‘-” ‘“’ :
.._. _@ (–). .~@
control circuit board.
No
AdjusI or replace
Normal door
1
Rum
continuity
door sensing switch.
sensing switch
i
(See page 11
1
(3) PROBLEM
,
Oven does not heat up.
I
I
1,
I ~~~~L~ti
a
I
3b
AC 240 Volts
I
I
I
I
I
Touch START key and
:
I
~)
measure voltage between
@
1
J@
.
white wire Iea[l and black
wire lead for primary
I
winding of H.V. trans.
I
o volts
Replace control
Runs
tormer afler removing
Normal control I
——. —.. —..
the wire le~ds from
circuit board,
circuit board
termtnals of H,V. trans.
:
I
—.—
former.
I
——
I
,,.:’,
.’
. . .
I
“-
}
.
.
i
L
c
..
,.:
u
L
i
LL
z
:
a
u
1-
U
-i -f
---- ---—- --- -----
-----
‘1
-.—.
.--—
+ +
-— --- ---- ----- ---- ----
6
‘--l
I
\/
.-
1
I
–13-
‘,..
,,
SEQUENCE RESULT
...
,.,,
,.
.....
.:,
.’
,,,:
.’..
,,,
‘, :
,,
,,,.
.’,.
,,
,.’.
,, .’
,,
,,,
.,
,,
!“
.,,,
,!,’
.,,,
,:
:,”,
,,,
.. . .
,,
“,
.,,
.’.
,,
,,,
.
,..’
,,,
,,
,,
.’.,’
: .,
.’:
,.’,
..,,.
.,.
,.
:.
,,..
,.,.
,.
:,,
‘.’..
,.,.,
.,..
,,,
,,
;,,
,,,
,“.’.
,,,
:,
.,,
....
.,.,
.,
...
:,:.
,,. .,
.
..’.
:.,.
.,.’
:.
,.,,
. .. . .
,,
,:.’
,. ,.
,...,
. .. .
.,..
UVLV
I
5) PROBLEM
‘he magnetron operates on
I
Iigh level when a lower cook
I
I
}ower is selected.
I
I
a
m
No problem.
Measure water
‘u
temperature
a
H.V. transformer.
rise exactly.
E
&
Voltage cycles
on and off.
i
I
I
m
I
Towh START key and
I
@
I a’.: ‘t
Set
fmwei level
fiie~stire volfage bebA@en
‘“” - ‘“”” ‘“- ‘“--”” -
.
. ..—.-. .
-,.
at “50”.
white wire lead and black
‘@
I
wire lead for primary
I
winding of H.V. trans-
240V
Replace control Normal control 1
Runs
former after removirq
circuit board.
I
the wire leads from
circuit board ,
terminals of H.V.
I
transformer.
I
I
I
I
I
1
[6) PROBLEM
I
No buzzing by touching keys
I
and at the end of cooking.
I
~-
!
I
I
1
I
I
@
: *’”.
I
‘@
Check normal operation
I
Replace control
Normal control
I
Runs
of control circuit board.
I
circuit board.
circuit board
I
I
I
:
. ,, .,
.’, ,
,.:~ :
.,, .
....
I
t
I
‘1
,,
Ell
9. Dl$AssEMf3LY INSTRUCTIONS
●
●
A.
OVEN MUST BE DISCONNECTED FROM ELECT-
RICAL OUTLET WHEN MAKING REpLACEMENTS,
REPAIRS,
ADJUSTMENTS
AND CONTINUITY
CHECKS BEFORE PROCEEDING WITH ANY RE-
REPAIR WORK AFTER DISCONNECTING. WAIT AT
LEAST I MINUTE, UNTIL THE CAPACITOR IN THE
HIGH-VOLTAGE AREA HAS FULLY DISCHARGED.
WHEN REPLACING ANY DOOR MICROSWITCH,
REPLACE WITH THE SAME TYPE SWITCH SPECIFIC
ED ON THE PARTS LIST.
REMOVING DOOR SENSING SWITCH
(Figures 1 on page 1, 14-a)
(1)
(2)
+.7 )
..““
(4)
(5)
Disconnect all wire leads from the door sensing
switch. (Figure 1 on page 1)
Remove 2 screws securing the lever stopper.
Push the door sensing switch upward while pressing
adjacent upper switch stopper of lever stopper and
lower switch slopper down (Figure 14-a).
Then remove it by lightly pressing the switch to-
ward you. (Figure 14-a).
Make necessary adjustments or replacements of the
door sensing switch by reversing step (3) and check
microwave energy leakage according to ‘“l. AD-
JUSTMENT PROCEDURES” on page 1, after it is
replaced with new one, and check proper operation
of it according to
“CHECKOUT PROCEDURE
FOR SWITCHES” on pagelo.
-.
Lower”
Switch
Stopper
Figure 14-a
Upper
Switch
Stopper
..
B. REMOVING PRIMARY INTERLOCK SWITCH AND
INTERLOCK IMONITOR SWfTCfi
(See Figure
}+b) -
(1)
(2)
(3)
Disconnect all wire leads from primary interlock
and interfock monitor switch.
Pull the primary interlock switch or interlock
monitor switch upward
at the same time while
pushing the switch stoppers to allow a space be-
tween the switch body and catches.
Make necessary adjustments or replacement of
switch by the reversing step (2) and check micro-
wave energy leakage according to “1. ADJUST-
MENT PROCEDURES” on page 1, after it is re-
placed with new one, and check proper operation
of it according to “CHECKOUT PROCEDURE
FOR SWfTCHES’” on pageltl
Switch Stoppers
x--
I
fcterlock
Monitor
, Switch
%/ I
Primary
Interlock
11 ,1
Switch
Switch stoppers
Figure 14-b
~
Interlock Swilch Replacement – when replacing
faulty switches be
sure sw]tch mounting tabs are not
bent, broken or o:herwlse deflclent In their ablllty
to secure the switches in place.
-15–
C. REMOVING BLOWER MOTOR
(Figures 15 (TOP
View) and 16)
(1) Remove screw securing the stay.
(2) Disconnect all lead wires from the blower motor
and H.V. capacitor.
(3) Remove 2 screws securing the blower base and
disengage 3 hooks from the rear plate of cavity
(Figure 15).
(4) Remove 1 screw securering the blower motor with
the blower base.
D. REMOVING MAGNETRON
(Figure 15 (TOP View))
After removing the blower motor:
(1)
(2)
(3)
(4)
(5)
Remove duct (msg. intake) and duct (msg. exhaust).
Remove 2 screws securing the thermal protector.
Disconnect 2 lead wires from the magnetron.
Remove 3 screws securing the magnetron to the
waveguide.
Take out magnetron VERY CAREFULLY’
NOTES
When removing the magnetron,
its dome does not hit any adiacent
be damaged.
make sure that
parts, or it may
When replacing the magnetron, be sure to install
the magnetron gasket in the correct position and be
sure that the gasket is in good condition.
– After replacing the magnetron, be sure to check
the microwave energy leakage with a leakage detec-
tor and confirm the leakage is below 5 mW/cm2.
Duct (msg. exhaust)
Blower base
\ I
L
,
/
I
Stay
I$uct (msg. intake)
Figure 15 (TOP view)
....
Screw
\
&~’r
;:::;.::::;
..::::;::
.........................
.-.....................
4
/4/
:..::::....:....-.::.
::::............
Z..
.:::-
. . .... .... ..::
::::......:::::--.::.<::
. . . ... .... . ... .. .: ......
. . .. .. . . ..
: :::::::..
:::::::::~
:::....:::;. .::::.:----
............. ...........
.................
::::...
lb
3 Hooks
.:::..- ...-
..................... ....
Blower Motor
\
Screws
Figure 16
.-.
.
.
E. REMOVING FUSE
Remove the 8A fuse with a screwdriver.
NOTES
—
When replacing the 8A fuse, b+?sure to use an
exact repair part.
If the 8A fuse blows immediately, check the
primary interlock switch, the relay 2 (on the control
circuit board) and the interlock monitor switch
according to “CHECKOUT PROCEDURE FOR
SWITCHES” on pagel O.And make sure to check the
microwave energy leakage according to “1. AD-
JUSTMENT PROCEDURES” on page 1, when the
primary interlock switch, the relay 2 or the inter-
lock monitor switch is adjusted or replaced.
– If the primary interlock switch, the relay 2 and
the interlock monitor switch operate properly,
determine which of the followings is defective:
control circuit board, blower motor, high voltage
transformer, high voltage capacitor, high voltage
—
diode or magnetron.
– If the high voltage diode is defective, replace not
only the high voltage diode but also the fuse diode,
F. REMOVING CONTROL CIRCUIT BOARD
(See exploded view on page 22 and Figure 17)
(1)
(2)
(3)
(4)
(5)
Remove the connector S1, S102 and the connector
for the relay 2 from the control circuit board.
Remove 1 screw securing the control panel com-
plete to the oven cavity,
Remove the FPC connector from the connector
S101 while grasping UP both lever
plastic fastener.
Remove 3 screws securing the control
to the control base.
Lift up the control circuit board from
and take it out from the control base.
ends of the
circuit board
its lower side
G. REMOVING TOUCH KEY BOARD
(Figure 18)
After removing the control circuit board;
(1)
(2)
(3)
Remove control base while lifting it up at the right
side and take it out from the control frame.
Remove control sheet which is glued to touch key
board.
Remove the touch key board which is held on the
control base bracket with the adhesive tape.
Control Base
Control Frame
Figure 17
Control Sheet
Touch
Key Board
–17–
H. REMOVING DOOR
1.
(1) Remove 2 hex nuts seturing the upper hinge.
(2) Tilt the top of the door toward you.
(3) Lift up the door to remove it.
NOTES
- After replacing the door, be sure to check that
the primary interlock switch, the door sensing
switch and, the interlock monitor switch operate
normally. (See page 1)
- After replacing the door, check for microwave
energy leakage with a leakage detector. Microwave
energy leakage must be below the limit of 5 mW/
cmz.
DISASSEMBLING DOOR
(Figure 19)
(1)
(2)
(3)
(4)
Insert a thin flat-blade screwdriver between the
choke dielectric and the door main frame and lift
up the choke dielectric to release hooks one by
one. (Figure 191
Remove the choke dielectric.
To detach the doot cover, Insert a thin flat-blade
screwdriver between door cover and the door panel
and release the projections inside door cover.
To detach the door panel, Insert a thin flat-blade
screwdriver between the door cover and door main
frame.
Hooks
Hooks
Door
Main
I
Choke
Dielectric
NOTES
– The choke dielectric may be damaged when it is
removed. When reinstalling it replace it with new
ones if they are damaged.
- Atter installing the door in the place, check for
microwave energy leakage with
a leakage detector.
Microwave energy leakage must be below the limit
of 5
mW/cm2.
J. REMOVING STIRRER FAN
(Figure 20)
(1) Release the 3 hooks of stirrer cover while pushing
them downward at the front of the cavity toP.
(2) Remove the stirrer cover from the hooks at the rear
side of the cavity top pulling it toward you.
Stirrer A’ssy
/
\,
\
Stirrer Cover
Figure 20
K. REMOVING TURNTABLE MOTOR COVER
(Figure 21)
(1)
(2)
(3)
(4)
Turn over the oven on its back.
Cut the 6-joints of the bottom plate using diagonal
pliers (nipper).
Separate the motor cover from bottom plate.
Remove 2 screws securing turntable motor to the
cavity and take it out.
Note: Bent the cut joints inside slignt[y for safety
and be careful of sharp edge.
Motor Cover
6 Joints
/
Bottom Plate
\
/
Figure 21
–18–
. . .
i
8. EXPLODED VIEW
AND PART LIST
CAVITY PARTS
21
a
16
II //
—
*** ALL SERVICE ON MICROWAVE OVENS SHOLJLD BE PERFORMED BY A QUALIFIED TECHNICIAN USING
APPROVED TESTING EQUIPMENT. CUSTOMERS SHOULD NOT ATTEMPT TO REPLACE PARTS IDENTIFIED
BY ATRIPLE ASTER ISK(***)
icy
No.
1
2
3
4
5
6
7
8
9
10
11
12
—
Part No.
6171246377
411 0825201
411 0654102
6171307450
6171246391
6170561600
411 0110802
6171240795
4110892500
411 001 4704
6171305616
617 120 B481
Description
Q’ty
Cabinet (Also order Circuit Diagram-
when replacing
Cabinet. J
1
Screw, Truss
Hd. Tapping, 4 x 10mm 11
Lockwasher, External Tooth, 4mm, U 2
Own Cavity***
(Not service Part) 1
Bottom Plate”
● “
1
Plastic Foot with Canoe Clip
4
Bolt, Hex. Hd. Machine with
Spring Washer & Bolt Washer,
5x 14mm, Zl ***
2
Hinge Lower”
● ”
1
Washer, 5mm, U
1
SCR S-TPG PAN 4 x 10mm
2
Gear Motor M2 LJ50ZA 12
1
Insulation Sheet
1
Key
Part No.
No.
Description
a’ty
13
14
6171147162 Turn table Shaft
1
15 617 1242416
Roller
1
16
617 1098372
Rotating Tray
1
17
61712 B1149
Ouct, Humidity Senser
1
18
617 1269994
Humidity Sensor
1
19
411 0076900
Screw, Pan Hal., Tapping, 3 x 6mm,
C2-2
1
20
617 1307481
Stirrer Cover
1
21
617 1265484
Stirrer A’ssy
1
22 617 1325720
Insulation Sheet
1
.
617 1385182
Name Plate
1
.
6171385175
Circuit Diagram
1
Items not illusmated.
–19–
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