Sharp R-3S68, Service Manual

Page: 15 / 36

R-3S68
13
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
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 defective parts.
CARRY OUT 4R CHECKS.
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary 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 OCCURANCE CAUSE OR CORRECTION
1 The rated voltage is not applied to POWER Check supply voltage and oven main unit.
terminal of CPU connector (CN-A).
2 The rated voltage is applied to primary side Low voltage transformer or secondary circuit defective.
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)
RY2
RY1
2
(J1)
CN - A
D22
VRS1
LEAD
WIRE
LEAD WIRE
GREEN
1
3
5
POWER OL TTM
b
a
c
d
M PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN