R-3C57
14
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
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 Panel
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the Key unit test (Procedure L) 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.
K
KEY UNIT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon is marking
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, disconnecct 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 marking 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 re-
placed. If a specific pad does not re-
spond, the above method may be used
(after clearing the control unit) to deter-
mine if the control unit or key pad is at
fault.
CARRY OUT 3D CHECKS.
Remove the outer case and check the voltage between Pin Nos. 3 and 5 of the 3 pin connector (A) on
the control unit with an A.C. voltmeter.
The meter should indicate 240 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
unit is defective.
L
RELAY TEST
G12
G11
G10
G9
G8
G7
G6
G5
G4
G3
G2
G1
KEY UNIT
5
4
3
2
1
0
9
8
7
6
AUTO
START
POWER
LEVEL
RICE
PASTA
INSTANT
COOK
START
DEFROST
Frozen
Dinner
CLOCK
TIMER
MEMORY
1
MEMORY
2
REHEAT
MEAT
VEGE-
TABLES
Pasta
Meal
STOP
CLEAR
HELP
LESS
MORE
