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R362M - 13

51-80

SEG39-SEG10

OUT

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

LSI signal (Pin No.)

LCD (Pin No.)

LSI signal (Pin No.)

LCD (Pin No.)
SEG 0 (90) ....................SEG39 (51)

SEG21 (69)

SEG19 (19)
SEG 1 (89) ....................SEG38 (50)

SEG22 (68)

SEG18 (18)
SEG 2 (88) ....................SEG37 (49)

SEG23 (67)

SEG17 (17)
SEG 3 (87) ....................SEG36 (48)

SEG24 (66)

SEG16 (16)
SEG 4 (86) ....................SEG35 (47)

SEG25 (65)

SEG15 (15)
SEG 5 (85) ....................SEG34 (46)

SEG26 (64)

SEG14 (14)
SEG 6 (84) ....................SEG33 (45)

SEG27 (63)

SEG13 (13)
SEG 7 (83) ....................SEG32 (44)

SEG28 (62)

SEG12 (12)
SEG 8 (82) ....................SEG31 (43)

SEG29 (61)

SEG11 (11)
SEG10 (80) ................... SEG30 (30)

SEG30 (60)

SEG10 (10)
SEG11 (79) ................... SEG29 (29)

SEG31 (59)

SEG 9 ( 9)
SEG12 (78) ................... SEG28 (28)

SEG32 (58)

SEG 8 ( 8)
SEG13 (77) ................... SEG27 (27)

SEG33 (57)

SEG 7 ( 7)
SEG14 (76) ................... SEG26 (26)

SEG34 (56)

SEG 6 ( 6)
SEG15 (75) ................... SEG25 (25)

SEG35 (55)

SEG 5 ( 5)
SEG16 (74) ................... SEG24 (24)

SEG36 (54)

SEG 4 ( 4)
SEG17 (73) ................... SEG23 (23)

SEG37 (53)

SEG 3 ( 3)
SEG18 (72) ................... SEG22 (22)

SEG38 (52)

SEG 2 ( 2) .....................SEG19 (71)

SEG21 (21)

SEG39 (51) .....................SEG 1 ( 1)

SEG20 (70)

SEG20 (20)

81

SEG9

OUT

Terminal not used.

82-90

SEG8-SEG0

OUT

Connected to LCD. Signal is similar to SEG39.

91

VCC

IN

Connected to GND.

92

VREF

IN

Connected to GND.

93

AVSS

IN

Connected to VC.

94

COM3

OUT

Terminal not used.

95

COM2

OUT

Connected to LCD (Pin No. 35).

96

COM1

OUT

Connected to LCD (Pin No. 34).

97

COM0

OUT

Connected to LCD (Pin No. 33).

98-99

VL3-VL2

IN

Standard voltage for LCD.

100

C2

IN

Terminal not used.

The I/O signal of the LSI(IZA961DR) are detailed in the following table.

R362M - 14

Changing the resistance values results in that there is
the same potential at both F-3 terminal of the absolute
humidity sensor and AN0 terminal of the LSI. The
voltage of AN1 terminal will indicate about -2.5V.  This
initial balancing is set up about 16 seconds after the
unit is put in the Sensor Cooking mode.  As the sensor
cooking proceeds, the food is heated to generate
moisture by which the resistance balance the bridge
circuit is deviated to increase the voltage available at
AN1 terminal of the LSI.
Then the LSI observes that voltage at AN1 terminal
and compares it with its initial value, and when the
comparison rate reaches the preset value (fixed for
each menu to be cooked), the LSI causes the unit to
stop sensor cooking; thereafter, the unit goes in the
next operation automatically.
When the LSI starts to detect the initial voltage at AN1
terminal 16 seconds after the unit has been put in the
Sensor Cooking mode, if it is not possible to balance,
of the bridge circuit due to disconnection of the absolute
humidity sensor, ERROR will appear on the display
and the cooking is stopped.

1) Absolute humidity sensor circuit

Sensing part
(Open vessel)

Sensing part
(Closed vessel)

Thermistors

ventilation opening for sensing

SW1

SW2

SW3

SW4

SW5

P54

P53

P52

P51

P50

 LSI
(IC1)

AN0

AN1

620k

300k

150k

75k

37.4k

14

9

17

18

10

16

15

47k

47k

IC2

10k

0.01uF

0.015uF

0.01uF

+

VA : -15V

VA : -15V

R90

C101

C102

C103

C104

S

F-2

1.8k

F-1

F-3

C

3.57k

3.32k

VC : -5V

0.1 uF

C. Thermistor in 
    closed vessel
S. Thermistor in
    open vessel

R107

R108

R112

R105

360k

R102

R101

R103

R104

D101

R109

R110

R111

R106

C

S

R3

R1

R2

+

Operational
amplifier

Output
voltage

S : Thermistor
     open vessel

C : Thermistor
      closed vessel

2

Absolute humidity (g/m  )

Output voltage

Absolute humidity vs,
output voltage characteristic

The absolute humidity sensor includes two thermistors as
shown in the illustration. One thermistor is housed in the
closed vessel filled with dry air while another in the open
vessel. Each sensor is provided with the protective cover
made of metal mesh to be protected from the external
airflow.

The figure below shows the basic structure of an absolute
humidity sensor. A bridge circuit is formed by two
thermistors and two resistors (R1 and R2).
The output of the bridge circuit is to be amplified by the
operational amplifier.
Each thermistor is supplied with a current to keep it heated
at about 150˚C (302˚F), the resultant heat is dissipated in
the air and if the two thermistors are placed in different
humidity conditions they show different degrees of heat
conductivity leading to a potential difference between
them causing an output voltage from the bridge circuit, the
intensity of which is increased as the absolute humidity of
the air increases. Since the output is very minute, it is
amplified by the operational amplifier.

This detector circuit is used to detect the output voltage of
the absolute humidity circuit to allow the LSI to control
sensor cooking of the unit.  When the unit is set in the
sensor cooking mode, 16 seconds clearing cycle occurs
than the detector circuit starts to function and the LSI
observes the initial voltage available at its AN1 terminal.
With this voltage given, the switches SW1 to SW5 in the
LSI are turned on in such a way as to change the
resistance values in parallel with R107 ~ R111 of IC2.

R362M - 15

Transistor
2SB1238

Transistor
KRC243M

approx. 1M ohm

This unit uses CMOS LSI in the integral part of the circuits.
When handling these parts, the following precautions
should be strictly followed. CMOS LSI have extremely
high impedance at its input and output terminals. For this
reason, it is easily influenced by the surrounding high
voltage power source, static electricity charge in clothes,
etc., and sometimes it is not fully protected by the built-in
protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them

in aluminium foil. Also wrap PW boards containing
them in aluminium foil.

2) When soldering, ground the technician as shown in

the figure and use grounded soldering iron and work
table.

We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the
precautions you must take when doing so.
To perform the servicing, power to the touch control panel
is available either from the power line of the oven itself or
from an external power source.

Therefore, when checking the performance of the
touch control panel, put the outer cabinet on the oven
to avoid touching the high voltage transformer, or
unplug the primary terminal (connector) of the high
voltage transformer to turn it off; the end of such
connector must be insulated with an insulating tape.
After servicing, be sure to replace the leads to their
original locations.

 On some models, the power supply cord between

the touch control panel and the oven itself is so
short that the two can't be separated.

For those models, check and repair all the controls
(sensor-related ones included) of the touch control

panel while keeping it  connected to the oven.

 On some models, the power supply cord between

the touch control panel and the oven proper is so
long enough that they may be separated from
each other. For those models, therefore, it is
possible to check and repair the controls of the
touch control panel while keeping it apart from
the oven proper; in this case you must short both
ends of the door sensing switch (on PWB) of the
touch control panel with a jumper, which brings
about an operational state that is equivalent to
the oven door being closed. As for the sensor-
related controls of the touch control panel,
checking them is possible if the dummy resistor(s)
with resistance equal to that of the controls are
used.

Disconnect the touch control panel completely
from the oven proper, and short both ends of the
door sensing switch (on PWB) of the touch control
panel, which brings about an operational state that
is equivalent to the oven door being closed. Connect
an external power source to the power input terminal
of the touch control panel, then it is possible to
check and repair the controls of the touch control
panel; it is also possible to check the sensor-
related controls of the touch control panel by using
the dummy resistor(s).

Tools required to service the touch control panel
assembly.
1) Soldering iron: 30W

(It is recommended to use a soldering iron with a
grounding terminal.)

2) Oscilloscope: Single beam, frequency range: DC

- 10MHz type or more advanced model.

3) Others: Hand tools

1) Before turning on the power source of the control

unit, remove the aluminium foil applied for
preventing static electricity.

2) Connect the connector of the key unit to the control

unit being sure that the lead wires are not twisted.

3) After aluminium foil is removed, be careful that

abnormal voltage due to static electricity etc. is not
applied to the input or output terminals.

4) Attach connectors, electrolytic capacitors, etc. to

PWB, making sure that all connections are tight.

5) Be sure to use specified components where high

precision is required.

R362M - 16

1. CARRY OUT 3D CHECKS.
2. Make sure that a definite "click" can be heard when the

microwave oven door is unlatched. (Hold the door in a
closed position with one hand, then push the door open
button with the other, this causes the latch heads to rise,
it is then possible to hear a "click" as the door switches
operate.)

3. Visually check the door and cavity face plate for damage

(dents, cracks, signs of arcing etc.).

Carry out any remedial work that is necessary before
operating the oven.
Do not operate the oven if any of the following conditions
exist;
1. Door does not close firmly.

2. Door hinge, support or latch hook is damaged.
3. The door gasket or seal is damaged.
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. There are defective  parts in the microwave generating

and transmission assembly.

7. There is visible damage to the oven.

Do not operate the oven:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.

Please refer to ‘OVEN PARTS, CABINET PARTS, DOOR PARTS’, when carrying out any of the following removal
procedures:

1. CARRY OUT 3D CHECKS.
2. Push the open button and open the door slightly.
3. Insert a putty knife (thickness of about 0.5mm) into the

gap between the choke cover and door frame as shown
in Figure C-5 to free engaging parts.

4. Release choke cover from door panel.
5. Now choke cover is free.

MONITOR SWITCH

STOP SWITCH

MONITORED
LATCH SWITCH

TAB

TAB

TAB

1. CARRY OUT 3D CHECKS.
2. Remove the control panel assembly referring to

"CONTROL PANEL ASSEMBLY REMOVAL".

3. Disconnect the all leads from the switches.
4. Remove the two (2) screws holding the latch hook to the

oven cavity.

5. Remove the latch hook.
6. Push the retaining tab slightly and remove the switch.

6. Release two (2) pins of door panel from two (2) holes of

upper and lower oven hinges by lifting up.

7. Now, door sub assembly is free from oven cavity.
8. Remove the four (4) screws holding the door panel to the

door frame.

9. Release door panel from eight (8) tabs of door frame by

sliding door panel downward.

10. Now, door panel is free.
11. Slide latch head upward and remove it from door frame by

releasing latch spring from door frame and latch head.

12. Now, latch head and latch spring are free.
13. Remove the two (2) screws holding the glass stopper to

the door frame.

14. Remove the glass stopper from the door frame.
15. Slide the front door glass leftwards and then slide

upwards to release the tabs holding it.

16. Now, the front door glass is free

10

5

4

12

8

7

9

11

3

2

1

Choke Cover

Door Frame

Putty Knife

6