Test Procedures; Touch Control Panel Assembly Test; Relay Test - Sharp R-310AK Supplemental Service Manual

PROCEDURE
LETTER
J

TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key
Unit, and also the Control Unit is divided into two units, CPU Unit and Power Unit, and troubleshooting
by replacement is described according to the symptoms indicated.
1. Key Unit.
The following symptoms indicate a defective key unit. Replace the 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.
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 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.
Note: When defective components, the Power Unit or Key Unit are replaced, the defective part or parts
must be properly packed for return in the shipping carton, with its cushion material, in which the
new replacement part was shipped to you.
L

RELAY TEST

Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and the common
terminal of the relay RY2 on the control unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY1 and RY2 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated ............. Defective relay.
DC. voltage not indicated ........ Check diode which is connected to the relay coil. If diode is good, control
RELAY SYMBOL
RY1
RY2

TEST PROCEDURES

COMPONENT TEST
Note : Check key unit ribbon connection before replacement.
unit is defective.
OPERATIONAL VOLTAGE
R-330AK/AW R-310AK
Approx. 24.5V D.C. Approx. 14.0 D.C.
Approx. 24.0V D.C. Approx. 12.8 D.C.
1
CONNECTED COMPONENTS
Oven lamp / Turntable motor / Cooling fan motor
Power transformer
R-310AK
R-330AK
R-330AW