O: Relay Test; P: Procedures To Be Taken When The Foil Pattern On The Printed Wiring Board (Pwb) Is Open - Sharp R-890SLM Service Manual

CARRY OUT 4R CHECKS.

[15] O: RELAY TEST

CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin Nos. 5 and 7 of the 4 pin connector (E) on the control unit with an A.C.
voltmeter. The meter should indicate 230-240 volts, if not check oven circuit.
Relay Test
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, grill operation, convection operation or
combi 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.
RELAY SYMBOL
RY1
RY2
RY3
RY4
RY5
RY6
RY7
CARRY OUT 4R CHECKS.
[16] P: PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the input circuit on the PWB, this foil pattern
acts as a fuse. If the foil pattern is open, follow the troubleshooting guide given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS
The rated AC voltage is not present between Pin Nos.
1
5 and 7 of the 4-pin connector (E).
The rated AC voltage is present at primary side of low
2
voltage transformer.
3 Pattern at "a" is broken.
NOTE: *At the time of these repairs, make a visual inspection of the varistor for burning
damage and examine the transformer with tester for the presence of layer short
circuit (check primary coil resistance).
If any abnormal condition is detected, replace the control unit.
CARRY OUT 4R CHECKS.
Service_R-890SLM.indd 19
W H 3 2 - W H 3 3 -
W H 3 1 -
E X P R S E S
A U T O C O
C O N I B
C O O K
SW1 SW4 SW11
S T O / P
S T A R T SHORT CUTS
C E L A R
SW13 SW15 SW9
KITCHEN TIMER
Q U C I K & E A
N I F O
/ CLOCK SET
SW14
SW10 SW8
C O N V ? ( .
G I R L L
A U T O M N I U T E
SW6 SW12
SW7
OPERATIONAL VOLTAGE
APPROX. 18.0V D.C.
APPROX. 18.0V D.C.
APPROX. 24.0V D.C.
APPROX. 24.0V D.C.
APPROX. 24.0V D.C.
APPROX. 24.0V D.C.
APPROX. 24.0V D.C.
OCCURRENCE
8 - 5
W H 3 4 -
O K
E N T E R
SW3
SY
M C I R O P O W E R
SW5
E X P R S E S
)
D E F R O S T
SW2
CONNECTED COMPONENTS
Oven lamp / Turntable motor
High voltage transformer
Grill (Top) heating element
Bottom heating element
Touch control transformer
Fan motor
Convection motor
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
Low voltage transformer or secondary circuit defective.
Check and replace the touch control transformer or the
control unit.
Replace the control unit.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
R-890SLM
a
4/25/09 10:55:24 AM