Sharp r-8580 Test Procedures Cont’D, Letter, Component, Checking Control Unit, Boardpwb Is Open

R-8580

TEST PROCEDURES (CONT’D)

PROCEDURE
LETTER	COMPONENT	TEST

CHECKING CONTROL UNIT

(1)Disconnect oven from power supply and remove outer case.

(2)Discharge the high voltage capacitor.

(3)Disconnect the wire leads from the cook relay.

(4)Disconnect the sensor connector that is mounted to lower position of control panel.

(5)Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.

(6)Reconnect the oven to the power supply and check the sensor cook operation proceed as follows:

6-1. Touch SENSOR COOK pad and number 0 pad.

6-2. The control panel is in the sensor cooking operation.

6-3. After approximately 20 seconds, push plunger of select switch. This condition is same as judgement by AH sensor.

6-4. After approximately 3 seconds, cooking operation turns off, an audible signal will sound, and the display will then revert to the time of day.

If the above is not the case, the control unit is probably defective. If the above is proper, the AH sensor is probably defective.

				To	Connector	(F)
				on	Control	Untt
						CONNECTOR
Rl, R2	: loon	t	1%	1/2w	F-l -
R3	: 10kR	? 5%		1/4W	F-2..--
R4	: 12kR	*	5%	1/4W	F-3 rc-

R4

R2iNO.

Plunger

0-J

NC

NO

I Switch

-2

Sensor Dummy Resistor Circuit

RPROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING

BOARD(PWB) IS OPEN.

To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB, and this fine pattern service as a substitute coil. If the foil pattern is open,

follow the troubleshooting guide given below for repair.

_.--

Problem: POWER CJN, indicator does not light up.

STEPS OCCURANCE CAUSE OR CORRECTION

1The rated voltage is not applied to POWER terminal Check supply voltage and oven main unit. of CPU connector (CN-A)

2 The rated voltage is applied to primarv side of Dower Power transformer or secondarv circuit defective.

NOTE:* At the time of these repairs, make visual in- spection of the varistor for burning damage and examine the transformer with tester for the presence of layer short-circuit (check primary coil resistance).

If any abnormalcondition is detected, replace the defective parts.

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