24
R-7A55(W)/(B)
R-7E45(W)/(B)
SERVICING
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.
B. On some models, the power supply cord between
the touch control panel and the oven proper is 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
dummy resistor(s) with resistance equal to that of
the controls are used.
(2) Servicing the touch control panel with power
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).
4. Servicing Tools
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
5. Other Precautions
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.
1. Precautions for Handling Electronic
Components
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 all 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.
2. Shapes of Electronic Components
3. Servicing of Touch Control Panel
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.
(1) Servicing the touch control panel with power
supply of the oven:
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING
SERVICING PRESENTS A HAZARD.
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
approx. 1M ohm
E
C B
E
C
B
Transistor
DTA114ES
DTA143ES
DTB143ES
DTC114ES
DTC143ES
2SA933S
Transistor
2SB910M
DTD143EA
