Touch Control Panel - Sharp R-380D Service Manual

PROCEDURE
LETTER
L 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 unit replacement is described according to the symptoms
indicated.
1. Key Unit. Note: Check key unit ribbon connection before replacement.
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 M) 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 troubles 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.
M KEY UNIT TEST
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 (stop 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 (stop 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 connector). 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.
CARRY OUT 3D CHECKS.
N RELAY TEST
Remove the outer case and check voltage between Pin No 2 of the 2-pin connector (A) and the normal
open terminal of the relay RY1 on the power unit with an A.C. voltmeter. The meter should indicate
230 - 240 volts, if not check oven circuit.
TEST PROCEDURES
COMPONENT TEST
G 8 G 7 G 6
G 9 5 4 3
0 9 8
G10
G11
MEAT CLOCK
STOP
G12 VEGETABLES
CLEAR
G13
HELP
G14
13
G 5 G 4 G 3 G 2
RICE/ EASY
2 1
PASTA DEFROST
EXPRESS
7 6
DEFROST
INSTANT
COOK
TIMER SOUP CASSEROLE
START
POWER SLOW
PIE
COOK
LEVEL
LESS
RICE
R-380D
G 1
MORE
DESSERTS
DINNER
PLATE
PIZZA