Control Panel Assembly - Electrolux MCD2660E Service Manual

Microwave ovens (middle grill)

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Table Of Contents

Table of Contents

The touch control section consists of the following units as shown in the touch control panel circuit.

(1) Switch Unit

(2) Control Unit

(3) LED Unit

(4) Relay Unit

The principal functions of these units and the signals communicated among them are explained below.

Switch Unit

The switch unit is composed of a matrix, signals generated in the LSI are sent to the switch unit

through P22, P23 and P24.

When a switch button is touched, a signal is completed through the switch unit and passed back to the LSI

through P50 and P51 to perform the function that was requested.

Control Unit

Control unit consists of LSI, power source circuit, relay circuit, back light circuit, synchronizing signal circuit,

reset circuit, buzzer circuit, and indicator circuit.

1) LSI

This LSI controls the tact switch strobe signal, relay driving signal, for oven function and indicator

signal.

2) Power Source Circuit

This circuit generates voltage necessary in the control unit.

Symbol

3) Synchronizing Signal Circuit

The power source synchronizing signal is available in order to compose a basic standard time in

clock circuit. It accompanies a very small error because it works on commercial frequency.

4) ACL Circuit

A circuit to generate a signals which resets the LSI to the initial state when power is supplied.

5) Buzzer Circuit

The buzzer is responsive to signals from the LSI to emit audible sounds (tact switch touch sound

and completion sound).

6) Stop Switch

A switch to "tell" the LSI if the door is open or closed.

7) Relay Circuit

To drive the magnetron, fan motor, turntable motor, heating element and light the oven lamp.

8) Indicator Circuit

This circuit consists of 4-digits, 12-segments and 3-common electrodes using a Liquid Crystal Display.

9) Encoder

The encoder converts the signal generated by LSI into the pulse signal, and the pulse signal is

returned to the LSI.

10) Back Light Circuit

A circuit to drive the back light (Light emitting diodes LD1 - LD3).

LED Unit

A circuit consisting of three light emitting diodes (LD1- LD3)which are driven by the control unit

and provide the backlight for the display.

Relay Unit

A circuit consisting of a relay (RY2) and a diode (D23) which

supply voltage to the heating element.

SOI 03.06 FV