Sharp Carousel R-326FS Service Manual - Page 18

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R - 326FS

PROCEDURE

LETTER

4) Run the oven and check all functions.

The following symptoms indicate a defective key unit.

a) When touching the pads, a certain pad produces no signal at all.

b) When touching a number pad, two figures or more are displayed.

c) When touching the pads, sometimes a pad produces no signal.

If the Key unit is defective.

1) Disconnect the power supply cord, and then remove outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Replace the Key unit.

5) Reconnect all leads removed from components during testing.

6) Re-install the outer case (cabinet).

7) Reconnect the power supply cord after the outer case is installed.

8) Run the oven and check all functions.

Control Unit

The following symptoms indicate a defective control unit. Before replacing the control unit, perform

the Key unit test (Procedure J) to determine if control unit is faulty.

2-1 In connection with pads.

a) When touching the pads, a certain group of pads do not produce a signal.

b) When touching the pads, no pads produce a signal.

2-2 In connection with indicators

a) At a certain digit, all or some segments do not light up.

b) At a certain digit, brightness is low.

c) Only one indicator does not light.

d) The corresponding segments of all digits do not light up; or they continue to light up.

e) Wrong figure appears.

f) A certain group of indicators do not light up.

g) The figure of all digits flicker.

2-3 Other possible problems caused by defective control unit.

a) Buzzer does not sound or continues to sound.

b) Clock does not operate properly.

c) Cooking is not possible.

When testing is completed,

1) Disconnect the power supply cord, and then remove outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Reconnect all leads removed from components during testing.

5) Re-install the outer case (cabinet).

6) Reconnect the power supply cord after the outer case is installed.

7) Run the oven and check all functions.

KEY UNIT TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable

is making good contact, verify that the door sensing switch operates properly; that is the contacts are

closed when the door is closed and open when the door is open. If the door sensing switch is good,

disconnect the flat ribbon cable that connects the key unit to the control unit and make sure the door

sensing switch is closed (either close the door or short the door sensing switch connecter). Use the

Key unit matrix indicated on the control panel schematic and place a jumper wire between the pins

that correspond to the STOP/CLEAR pad making momentary contact. If the control unit responds by

clearing with a beep the key unit is faulty and must be replaced. If the control unit does not respond,

it is faulty and must be replaced. If a specific pad does not respond, the above method may be used

(after clearing the control unit) to determine if the control unit or key pad is at fault.

TEST PROCEDURES

COMPONENT TEST