R-362M (serv.man2) - Sharp Home Appliance Service Manual (repair manual). Page 7

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R362M - 7
COMPONENT TEST
NOTE: *At the time of these repairs, make a
visual inspection of the varistor for burn-
ing damage and examine the trans-
former with tester for the presence of
layer short circuit (check primary coil
resistance).
If any abnormal condition is detected,
replace the defective parts.
CARRY OUT 4R CHECKS.
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 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.
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
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY2
Approx. 18.0V D.C.
High voltage transformer
RY5
Approx. 24.0V D.C.
Fan motor / Turntable motor / Oven lamp
CARRY OUT 4R CHECKS.
(J1)
9
8
a
d
c
b
C2
VRS1
RY3
5 FAN
AC 1 - 5
     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
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.)
4
Pattern at "a" and "b" are broken.
*Insert the coil RCILF2003YAZZ between "c" and "d".
(CARRY OUT 3D CHECKS BEFORE REPAIR.)
PROCEDURE
LETTER
C
RELAY TEST
D
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
TEST PROCEDURE (CONT'D)
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