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8

750A -

29

R42

OUT

To turn on and off the cook relay
(RY3). In 100% POWER opera-
tion, the signals hold "L" level
during microwave cooking and
"H" level while not cooking. In
other cooking modes (70%,
50%, 30%, 10%) the signal turns
to "H" level and "L" level in  rep-
etition according to the power
level.

30

R43

OUT

To turn on and off shut off relay (RY1). The
square waveform voltage is delivered to
the RY1 driving circuit.

31

R50

IN

Signal coming from touch key.
When any one of  G-1 line keys on key matrix is touched, a corresponding signal from
R60, R61, R62, R63, R72 and R73 will be input into R50. When no key is touched,
the signal is held at "H" level.

32

R51

IN

Signal similar to R50.
When any one of  G-2 line keys on key matrix is touched, a corresponding signal will
be input into R51.

33

R52

IN

Signal similar to R50.
When any one of  G-3 line keys on key matrix is touched, a corresponding signal will
be input into R52.

34

R53

IN

Signal similar to R50.
When any one of  G-4 line keys on key matrix is touched, a corresponding signal will
be input into R53.

35

R60

OUT

Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R50 - R53 terminal
while one of G5 line keys on key matrix is touched.

36

R61

OUT

Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R50 - R53 terminal
while one of G6 line keys on key matrix is touched.

37

R62

OUT

Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R50 - R53 terminal
while one of G7 line keys on key matrix is touched.

38

R63

OUT

Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R50 - R53 terminal
while one of G8 line keys on key matrix is touched.

39-40

R70-R71

OUT

Terminal not used.

41

R72

OUT

Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R50 - R53 terminal
while one of G10 line keys on key matrix is touched.

42

R73

OUT

Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R50 - R53 terminal
while one of G9 line keys on key matrix is touched.

ON/OFF time ratio in
Micro cooking
(a. 48second time base)

ON/OFF time ratio in
Micro cooking
(a. 32second time base)

MICRO

ON

OFF

COOK
100%

32sec.

0sec.

70%

24sec.

8sec.

50%

18sec.

14sec.

30%

12sec.

20sec.

10%

6sec.

26sec.

MICRO

ON

OFF

COOK
100%

48sec.

0sec.

70%

36sec.

12sec.

50%

26sec.

22sec.

30%

16sec.

32sec.

10%

8sec.

40sec.

20.0 msec

During cooking

H : +5V

L : 0V

9

750A -

43-54

SEG0 -

OUT

SEG11

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 (1) ............................. S12(4)

SEG 6 (7) ......................... S6(10)

SEG 1 (2) ............................. S11(5)

SEG 7 (8) ......................... S5(11)

SEG 2 (3) ............................. S10(6)

SEG 8 (9) ......................... S4(12)

SEG 3 (4) ............................... S9(7)

SEG 9 (10) ....................... S3(13)

SEG 4 (5) ............................... S8(8)

SEG 10 (11) ..................... S2(14)

SEG 5 (6) ............................... S7(9)

SEG 11 (12) ..................... S1(15)

55-57

SEG12-

OUT

Terminal not used.

SEG14

58

VDD

IN

Power source voltage input terminal.
Connected to GND.

59-64

SEG15-

OUT

Terminal not used.

SEG20

WARNING: Before carrying out any work carry out 3D checks

1) Disconnect the supply.

2) Door opened, and wedged open.

3) Discharge high voltage capacitor.

Ensure the following:

1.

Wires must not touch:

a)

High voltage parts.
(Magnetron, high voltage transformer, high voltage capacitor and high voltage rectifier assembly)

b)

Parts that become hot.
(Heating elements, oven lamp, oven cavity magnetron and high voltage transformer)

c)

Sharp edges.
(Bottom plates, oven cavity, waveguide flange, chassis support and other metallic parts)

d)

Movable parts.
(Fan blade, any motor, switch, switch lever and open button)

2.

Positive lock connectors are fitted correctly.  Ensure the locking pin is located correctly.

3.

Wires are connected correctly as per pictorial diagram.

4.

No wire leads are trapped by the outer wrap.

10

750A -

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.

approx. 1M ohm

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.

A. 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.

Transistor
2SB1238

Transistor
DTA123ES
KRA101M
KRA223M
KRC243M

B. 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.

supply from an external power source:
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.

10

750A -

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.

approx. 1M ohm

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.

A. 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.

Transistor
2SB1238

Transistor
DTA123ES
KRA101M
KRA223M
KRC243M

B. 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.

supply from an external power source:
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.