Read Sharp R-85STMA (serv.man9) Service Manual online
the touch control panel circuit.
among them are explained below.
sent to the key unit from P40, P41, P72, P73, P74, P75, P76 and P77.
and passed back to the LSI through P44 - P47 to perform the function
that was requested.
circuit, reset circuit, buzzer circuit, relay circuit, temperature measure-
ment circuit, indicator circuit and back light circuit.
signal, relay driving signal for oven function and indicator signal.
pose a basic standard time in the clock circuit. It accompanies a
very small error because it works on commercial frequency.
state when power is supplied.
sounds (key touch sound and completion sound).
ment, convection motor, fan motor, turntable motor, touch control
transformer and light the oven lamp.
trodes using 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
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 or from an external
PRESENTS A HAZARD.
related ones included) of the touch control panel while keeping it
connected to the oven.
arated from each other. For those models, therefore, it is possi-
ble to check and repair the controls of the touch control panel
while keeping it apart from the oven; 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.
short both ends of the door sensing switch (on PWB) of the touch
control panel, which brings about an operational state that is equiv-
alent 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).