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R-9200
1.
SERVICING
Precautions
for
Handling
Electronic
Components
This unit uses PMOS LSI in the integral
part of the
circuits.
When handling
these parts, the following
precautions
should
be strictly
followed.
PMOS
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
PMOS LSI.
1) When
storing
and
transporting,
thoroughly
wrap them in aluminum
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.
* . J
approx.
1 MR
h
h
2.
Shapes
of Electronic
Components
Transistor
Transistor
288793
DTDl43EA
Transistor
DTA143ES
DTBl43ES
KRA102M
KRCl02M
2SA933S
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 con-
trol panel is available
either from the power line of
the oven itself or from an external
power source.
(I) 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
PRESENT
A HAZ-
ARD.
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 servic-
ing, be sure to replace the leads to their original
locations.
A.
On some models,
the power
supply
cord be-
tween the touch
control
panel and the oven it-
self is
SO
short that the two can't be separated.
B.
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 be-
tween
the touch
control
panel
and the oven
proper is long enough
that they may be sepa-
rated
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 stop
switch
(on PWB)
of the touch
control
panel
with
a jumper,
which
brings
about
an opera-
tional
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 stop 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 - IOMHz
type
or more ad-
vanced model.
3)
Others:
Hand tools
5.
Other
Precautions
I>
2)
3)
4)
5)
Before
turning
on the
power
source
of the
control
unit, remove the aluminum
foil applied
for preventing
static electricity.
Connect
the connector
of the key unit to the
control
unit being sure that the lead wires are
not twisted.
After aluminum
foil is removed,
be careful that
abnormal
voltage
due to static electricity
etc. is
not applied to the input or output
terminals.
Attach
connectors,
electrolytic
capacitors,
etc.
to PWB, making
sure that all connections
are
tight.
Be sure to use specified
components
where
high precision
is required.
('RD94ZA2U)
20
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