Sharp R-8470, Руководство по обслуживанию

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R-8470
R-8570
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following
units as shown in the block diagram.
(1) Control Unit
(2) Key Unit
(3) Relay Unit
Exchange of signals between each unit is indicated by
the arrows in the block diagram. The principal func-
tions of these units and the signal communicated
among them are explained below.
Relay unit consists of six relays power
source circuit and buzzer circuit.
The key unit is composed of a matrix, signals generated
in the LSI are sent to the key unit through
El 1 -El 3and El
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI
through
to perform the function that was
requested.
Control unit consists of LSI, power source circuit,
synchronizing signal circuit, ACL circuit, buzzer circuit,
temperature measurement circuit, absolute humidity
sensor circuit and indicator circuit.
This LSI controls the temperature measurement
signal, AH sensor
strobe signal relay
driving signal for oven function and indicator sig-
nal.
This circuit generates voltage necessary in the
control unit.
Symbol Voltage Application
VC
-5v (ICI), ACL circuit and tem-
perature measurement circuit
VP
-15v Buzzzer circuit and IC2
IC2 (R-8570 only)
-34v Fluorescent display tube : Grid
and anode voltage
-25V Filament of fluorescent display
tube
VF2
-28V VF2 voltage
The power source synchronizing signal is available
in order to compose a basic standard time in the
clock circuit.
It accompanies a very small error because it works
on commercial frequency.
Cirucit to generate signals resetting the LSI to the
initial state when power is supplied.
The buzzer is responsive to signals from the LSI
to emit noticing sounds (key touch sound and
completion sound).
The temperature in the oven cavity is sensed by the
thermistor.
The variation of resistance according to sensed
temperature is detected by the temperature meas-
urement circuit and the result applied to LSI.
The result of detecting is given to LSI controlling
the relay and display.
The circuit detects absolute humidity of a food
which is under cooking, to allow its automatic
cooking.
to “tell” the LSI if the door is open or
To drive the magnetron, heating element, fan mo-
tor, convection motor,damper motor, turntable
motor and light the oven lamp.
Indicator element is a Fluorescent Display.
Basicalloy, a Fluorescent Display is triode having a
cathode, a grid and an anode. Usually, the cathode
of a Fluorescent Display is directly heated and the
filament serves as cathode.
The Fluorescent Display 7-digits, 15-segments are
used for displaying figures.
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