Read Sharp R-895M (serv.man6) Service Manual online
R-895M - 18
PROCEDURE
LETTER
COMPONENT TEST
control unit with an A.C. voltmeter.
The meter should indicate 230-240 volts, if not check oven circuit.
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 dual operation.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, grill
operation, convection operation or dual operation.
DC. voltage indicated .......... Defective relay.
DC. voltage not indicated .... Check diode which is connected to the relay coil. If diode is good,
DC. voltage not indicated .... Check diode which is connected to the relay coil. If diode is good,
control unit is defective.
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY1
Approx. 18.0V D.C.
Oven lamp / Turntable motor
RY2
Approx. 18.0V D.C.
High voltage transformer
RY3
Approx. 24.0V D.C.
Grill (Top) heating element
RY4
Approx. 24.0V D.C.
Bottom heating element
RY5
Approx. 24.0V D.C.
Touch control transformer
RY6
Approx. 24.0V D.C.
Fan motor
RY7
Approx. 24.0V D.C.
Convection motor
CARRY OUT 4R CHECKS..
P
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
(PWB) IS OPEN
CARRY OUT 3D CHECKS.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
1
The rated AC voltage is not present between
Check supply voltage and oven power cord.
Pin Nos. 1 and 3 of the 4-pin connector (E).
2
The rated AC voltage is present at primary
Low voltage transformer or secondary circuit defective.
side of low voltage transformer.
Check and repair.
3
Only pattern at “a” is broken.
*Insert jumper wire J1 and solder.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
(CARRY OUT 3D CHECKS BEFORE REPAIR)
4
Pattern at “a” and “b” are broken.
*Insert the coil RCILF2003YAZZ between “c” and “d”.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
(CARRY OUT 3D CHECKS BEFORE REPAIR)
NOTE: *At the time of these repairs, make a visual
inspection of the varistor for burning dam-
age and examine the transformer with tester
for the presence of layer short circuit (check
primary coil resistance).
age and examine the transformer with tester
for the presence of layer short circuit (check
primary coil resistance).
If any abnormal condition is detected, re-
place the defective parts.
place the defective parts.
CARRY OUT 4R CHECKS.
CN-A
CN-E
D12
7
(J1)
D13
VRS1
a
c
d
b
TEST PROCEDURES
O
RELAY TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 4 pin connector (E) on the
