Touch Control Panel Assembly - Electrolux EI30SM55JB Technical & Service Manual

Touch Control Panel Assembly

OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units.
(1) Glass touch key
(2) Control Unit
The principal functions of these units and the signals
communicated among them are explained below.
Glass Touch Key Unit
The glass touch key unit is composed of a matrix, signals
generated in the LSI are sent to the glass touch key unit.
When a key pad is touched, a signal is completed
through the glass touch key unit and passed back to the
LSI to perform the function that was requested.
1. IC3
This is the IC to judge the selected key.
Control Unit
Control unit consists of LSI, IC, reset circuit, indicator
circuit, power source circuit, relay circuit, buzzer circuit,
synchronizing signal circuit, glass touch key unit circuit
and humidity sensor circuit.
1. IC1 (LSI):
This is a microcomputer, responsible for controlling
the entire control unit.
2. IC2:
This is the IC to amplify the signal from the humidity
sensor.
3. Reset Circuit:
This circuit generates a signal which resets the LSI
(IC1) to the initial state when power is supplied.
4. Indicator Circuit:
Indicator element is Fluorescent Display. Basically, 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 has 8-digits,
16-segments are used for displaying figures.
5. Power Source Circuit:
This circuit generates voltages necessary in the
control unit from the AC line voltage. In addition, the
synchronizing signal is available in order to compose
a basic standard time in the clock circuit.
Symbol Voltage
VC +5V
Application
LSI(IC1)
2-7
6. Relay Circuit:
A circuit to drive the magnetron, fan motor, stirrer
motor, hood motor and light the oven lamp and cook
top lamp.
7. Buzzer Circuit:
The buzzer is responsive to signals from the LSI to
emit audible sounds (key touch sound and
completion sound).
8. Synchronizing Signal Circuit:
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.
9. Door Sensing Switch:
A switch to "tell" the LSI if the door is open or closed.
10. Humidity Sensor Circuit:
This circuit detects moisture of the cooking food to
allow its automatic cooking.
Operation