Sharp R-2397 Control Unit, Power Supply Circuit, ACL Circuit, Clock Circuit, IC1 Main Processor

R-2397

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL

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

(1)Control Unit

(2)Key Unit

The principal functions of these units and the signals commu- nicated among them are explained below.

1.Control Unit

Signal of key touch and oven function control are all processed by one microcomputer.

1)Power Supply Circuit

This circuit changes output voltage at the secondary side of the low voltage (T1) transformer to volatges required at each part by full wave rectifying circuit, constant voltage circuit, etc..

2)ACL Circuit

This AC voltage is then half wave rectified by D61/D62 and smoothed (filtered) by C61/C62.

This AC voltage is the input to the IN3 and IN5 ports of IC1, which determines if there is a magnetron / high voltage problem.

HIGH VOLTAGE TRANSFORMER

				HIGH VOLTAGE CIRCUIT
				MAIN BODY SIDE
CT1 or CT2				T/C SIDE
RY3 or RY4
R61 or	R65 or
R62	R66
			C61 or C62
				IC1
D61 or	R63 or	D63 or		IN3 or
				IN5 PORT
D62	R64	D64

This is an Auto-clear Circuit, i.e., a reset circuit, which enables IC1 to be activated from initial state.

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3)Power SYNC Signal Generating Circuit

This is a circuit for generating power SYNC signal by virtue of the secondary side output of transformer T1. This signal is used for a basic frequency to time process- ing and so on.

4)Clock Circuit

This is a circuit for controlling clock frequency required for operating IC1.

5)IC1 (Main Processor)

This is a one-chip microcomputer, responsible for con- trolling the entire control unit.

6)IC2 (Memory Processor)

This is a memory IC, responsible for memory function.

7)Display Circuit

This is a circuit for driving display tubes by IC1 output.

8)Key Input Circuit

This is a circuit for transmitting key input information to IC1.

9)Sound-body Driving Circuit

This is a circuit for driving sound body by IC1 output.

10) Relay Driving Circuit

This is a circuit for driving output relay by IC1 output.

11) Stop Switch Circuit

This is a circuit for driving IC1 to detect door opening/ closing.

12) Exhaust Air Temperature Detecting Circuit

This is a circuit for transmitting output change of thermistor (Exhaust Air Temperature Sensor) to IC1.

13) High Voltage Monitoring Circuit.

This circuit detects problems in the magnetron / high voltage circuit by sensing a variation in the current flowing through the primary winding of the high voltage transformer.

During heating, the primary current of the high voltage transformers also flows through the primary winding of the current transformers CT1 and CT2. This causes a current to be induced in the secondary windings of CT1/ CT2 and results in an AC voltage which is determined by R61/R62.

Figure T-1. High Voltage Monitoring Circuit

14)Magnetron Temperature Circuit. (Detect Noload or Fan Lock)

This is a circuit for transmitting output change of thermistor (Magnetron Temperature Sensor) to IC1.

15) Intake Air Temperature Detecting Circuit.

This is a circuit for transmitting output change of thermistor (Intake Air Sensor) to IC1.

2. Key Unit

The key unit is composed of a matrix circuit in which when a key it touched, one of signals P11, P12, P15, P16 and P17 generated by the LSI, is passed through the key and returned to the LSI as one of signals R0--R3. This model has 20 Memory pads. When the oven is shipped, Memory pad 1 to 10 are set as follows: fig.1.

Memory No.	Cook Time	Output Power
1	5sec.	100%
2	10sec.	100%
3	20sec.	100%
4	30sec.	100%
5	40sec.	100%
6	50sec.	100%
7	1min.	100%
8	1min.15sec.	100%
9	1min.30sec.	100%
10	2min.	100%
	(fig. 1)

This model has a double quantity pad. When the oven is shipped, Magnification "1.8" is preset in the double quantity pad. This model has an defrost pad. When the oven is shipped, defrost is set as follows: fig.2.

		1 STAGE
POWER		10%
OVEN ON/OFF		ON
	(fig. 2)

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