Read Sharp R-959SLMA (serv.man9) Service Manual online
trol panel circuit.
and Control unit.)
among them are explained below.
sent to the key unit from P50 – P57. When a key pad is touched, a sig-
nal is completed through the key unit and passed back to the LSI
through P44 – P47 to perform the function that was requested.
circuit, ACL circuit, buzzer circuit, relay circuit, temperature measure-
ment circuit, indicator circuit, absolute humidity sensor circuit and back
strobe signal, relay driving signal for oven function and indicator
pose a basic standard time in the clock circuit. It accompanies a
very small error because it works on commercial frequency.
when power is supplied.
sounds (key touch sound and completion sound).
element, convection motor, fan motor, turntable motor, damper
motor, touch control transformer and light the oven lamp.
a Liquid Crystal Display.
variation of resistance according to sensed temperature is detected
by the temperature measurement circuit and the result applied to
LSI. The LSI uses this information to control the relay and display
been used for 3 minutes or more, the circuit will be opened and the
control unit will not be energized.
dling these parts, the following precautions should be strictly followed.
CMOS LSI have extremely high impedance at its input and output ter-
minals. 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.
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 exter-
nal power source.
PRESENTS A HAZARD.
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.
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.
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 exter-
nal 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).