Dacor DCM24B Service Manual

Also see for DCM24B: Use and care manual

Contents

Dacor DCM24B Service Manual Manual pdf 28 page image

25DCM24BDCM24RDCM24SThe touch control section consists of the following unitsas shown in the touch control panel circuit.(1) Key Unit(2) Control UnitThe principal functions of these units and the signals com-municated among them are explained below.Key UnitThe key unit is composed of a matrix, signals P10 - P17generated in the LSI are sent to the key unit.When a key pad is touched, a signal is completed throughthe key unit and passed back to the LSI through R24 - R27to perform the function that was requested.Control UnitControl unit consists of LSI, power source circuit, synchro-nizing signal circuit, ACL circuit, buzzer circuit, temperaturemeasurement circuit, absolute humidity sensor circuit andindicator circuit.1) LSIThis LSI controls the temperature measurement signal,AH sensor signal, key strobe signal, relay driving signalfor oven function and indicator signal.2) Power Source CircuitThis circuit generates the voltages necessary for thecontrol unit from the AC line voltage.3) Synchronizing Signal CircuitThe power source synchronizing signal is available inorder to compose a basic standard time in the clockcircuit. It incorporates a very small error because it workson commercial frequency.TOUCH CONTROL PANEL ASSEMBLYOUTLINE OF TOUCH CONTROL PANEL4) ACL CircuitA circuit to generate a signals which resetting the LSI tothe initial state when power is applied.5) Buzzer CircuitThe buzzer is responds to signals from the LSI to emitnoticing sounds (key touch sound and completion sound).6) Temperature Measurement Circuit : (OVENTHERMISTOR)The temperature in the oven cavity is sensed by thethermistor. The variation of resistance according to sensedtemperature is detected by the temperature measurementcircuit and the result applied to LSI. The LSI uses thisinformation to control the relay and display units.7) Absolute Humidity Sensor CircuitThis circuit detects the humidity of a food which is beingcooked, to control its automatic cooking.8) Door Sensing SwitchA switch to inform the LSI if the door is open or closed.9) Relay CircuitTo drive the magnetron, heating element, fan motor,convection motor, damper motor, turntable motor andlight the oven lamp.10) Indicator CircuitIndicator element is a Fluorescent Display.Basically, a Fluorescent Display is triode having a cathode,a grid and an anode. Usually, the cathode of a FluorescentDisplay is directly heated and the filament serves ascathode.The Fluorescent Display has 8-digits, 16-segments areused for displaying figures.DESCRIPTION OF LSILSI(IXA103DR):The I/O signals of the LSI(IXA103DR) are detailed in the following table.Pin No. Signal I/O Description1 VCC IN Connected to GND.2 VEE IN Anode (segment) of Fluorescent Display light-up voltage: -30V.Vp voltage of power source circuit input.3 AVSS IN Power source voltage: -5V.VC voltage of power source circuit input.4 VREF IN Reference voltage input terminal.A reference voltage applied to the A/D converter in the LSI. Connected to GND.(0V)