Sharp MMD24S, MMD24B manual Test Procedures, Component Test, Letter, Checking Control Unit

MMD24S

MMD24B

TEST PROCEDURES

PROCEDURE	COMPONENT TEST
LETTER

9-2. Place the container on the center of tray in the oven cavity.

9-3. Close the drawer.

9-4. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and the START pad once. And touch the number pads 1 once and the number pad 4 once.

9-5. The control panel is in automatic Sensor operation.

9-6. The oven turns off automatically, and the time for detecting moisture will be displayed.

If new sensor does not operate properly, the problem is with the control unit, and refer to explanation be- low.

CHECKING CONTROL UNIT

(1)Disconnect the power supply cord, and then disassemble as per "MICROWAVE DRAWER DISASSEMBLY" page 27.

(2)Open the drawer and block it open.

(3)Discharge high voltage capacitor.

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

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

(6)Disconnect the leads to the primary of the power transformer.

(7)Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.

(8)After that procedure, re-connect the power supply cord.

(9)Check the sensor cook operation proceed as follows:

9-1. Close the door. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and the START pad once. And touch the number pads 1 once and the number pad 4 once.

9-2. The control panel is in the sensor cooking operation.

9-3. After approximately 25 seconds, push plunger of select switch for more than 3 seconds.This condition is same as judgement by AH sensor.

9-4. After approximately 3 seconds, the display shows “ X X . X X “ which is the time for detecting moisture.

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

(10)Disconnect the power supply cord, and then remove covers.

(11)Open the drawer and block it open.

(12)Discharge high voltage capacitor.

(13)Disconnect the dummy resistor circuit from the sensor connector of control panel.

(14)Carry out necessary repair.

(15)Reconnect all leads removed from components during testing and repairing.

(16)Re-install the covers.

(17)Reconnect the power supply cord after the outer case is installed. Run the oven and check all functions.

(18) Carry out "Water load cooking test" again and ensure that the oven works properly.

R1, R2 : 22Ω ± 1% 1/2W

R3 : 4.3kΩ ± 5% 1/4W

R4 : 1MΩ ± 5% 1/4W

Plunger

NC

NO

	To connector (F)				COM
	on Control Unit.
F-1	1				NO
	2			COM
F-2		R1
	3
F-3		R2	R3	R4	NC
	CONNECTOR

15