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R-9370
SERVICING
1.
2.
Shapes
of Electronic
Components
3.
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
an.d
output
terminals.
For this reason,
it is easily
influenced
by
the surrounding
high voltage
power
source,
static
electric-
ity charged
in clothes,
etc, and sometimes
it is not fully pro-
tected
by the
built-in
protection
circuit.
1) When
storing
and transporting,
thoroughly
wrap
them
in aluminum
foil.
Also wrap
PW boards
containing
them
in aluminum
foil.
2) When
soldering,
ground
the technician
as shown
in the
figure
and use grounded
soldering
iron and wbrk
table.
. .
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Transistor
Transistor
Regurator IC
Hybrid
IC
2SB953
DTCI
14EA
AN79L12
IC3, IC4
1: OUT
Terminal
COMMON
Terminal
IN Terminal
Servicing of Touch Control
Panel
We describe
the
procedures
to
permit
servicing
the touch
control panel of the microwave oven and the cautions you
must consider when doing so.
To
carry
out servicing, power supply to the touch control
panel is available either from the power line of the oven
proper itself of from an external power source.
(1)
Servicing
the touch
control
panel
with
power
supply
from the oven proper:
CAUTION:
THE
HIGH
VOLTAGE
TRANSFORMER
OF
THE
MICROWAVE
OVEN
IS
STILL
ALIVE
TO
GIVE
YOU
DANGER
DURING
SERVICING.
[Therefore,
when checking the performance of the
touch control panel, put the outer cabinet on the oven
proper
to
keep
you
from
touching
the
high
voltage
transformer,
or
unplug
the
promary
terminal
(con-
nector)
of the high voltage
transformer
to turn
it off;
and the end of such connector shall be insulated with
an insulating tape.
After
servicing,
be sure to replace
the
leads to their original locations.
20
A.
On some
models,
the power
supply
cord
between
the
touch
control
panel and the oven
proper
is so short
that
they
can't
be separated
from
each
other.
For those models,
therefore,
check
and repair all the con-
trols
(with the sensor-related
ones included)
of the touch
control
panel
while
keeping
it in contact
with
the oven
proper.
B.
On some models, on the other hand,
the power
supply
cord
between
the
touch
control
panel
and the
oven
proper
is so long that they
may be separated
from
each
other.
For those
models,
therefore,
it is allowed
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 operational
state that is equivalent
to that
with
the
oven
door
being
closed.
As to the sensor-re!ated
controls
of the touch
control
panel,
their checking
is allowed
if the dummy
resistor(s)
whose
resistance
is equal
to that
of those
controls
is
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
such an operational
state
that
is equivalent
to that
with
the
oven
door
being
closed.
And
connect
an external
power
source
to the power
input
terminal
of the touch
control
panel,
and then
it is allowed
to check
and repair
the controls
of the touch
control
panel;
as in the case
of
(1 )-B above,
it is here
also
possible
to check
the
sensor-related
controls
of the touch
control
panel by us-
ing the dummy resistor(s).
4. Sevicing
Tools
Tools
required
when
servicing
the touch
control
panel
as-
sembly.
1) Soldering:
30W
(To
prevent leaking current, it is recommended to use
a soldering
iron with
grounding
terminal.)
2) Oscilloscope:
Single
beam,
frequency
range:
DC
-
10MHz
type
or more
advanced
model
3) Others:
Other
tools
5. Other
Precautions
1) When
turning
on the power
source
of the control
unit,
remove
the aluminum
foil applied
for preventing
static
electricity.
2) Connect
the connectors
of the indicator
and key units
to the control
unit
taking
care that
the
lead wires
are
not
twisted.
3) After
alu,minum
foil is removed,
take extra
care that
ab-
normal
voltage
due to static
electricity
etc.
is not
ap-
plied
to the Input
or output
terminals.
4) Attach
connectors,
electrolytic
capacitors,
etc.
to PW
board,
taking
care that
all connections
are tight.
5) Be sure to use specified
components
where
high preci-
sion
is required.
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