Procedure K: Key Unit Test - Sharp R-306LK Service Manual

Microwave oven r-306lk; r-306lw

Hide thumbs Also See for R-306LK:

Operation manual (25 pages)

Table Of Contents

Table of Contents

R306LW

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

8) Run the oven and check all functions.

2. Control Unit.

The following symptoms indicate a defective control unit. Before replacing the control unit, perform the Key unit test (Procedure K) to determine if con-

trol unit is faulty.

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) 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.

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.

[12] Procedure K: 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. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check the circuit between the pins of the key unit that

correspond to the STOP/CLEAR pad. When the pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the ohmme-

ter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and must be replaced. About the other pads, the above

method may be used.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

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

8. Run the oven and check all functions.

MINUTE

PLUS

TIMER

POPCORN

CLOCK