Sharp R-310AK Supplemental Service Manual page 4

R-310AK
R-330AK
R-330AW
PROCEDURE
LETTER
N 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 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.
STEPS
1
2
3
4
NOTE: *At the time of making these repairs,
TEST PROCEDURES
OCCURRENCE
The rated AC voltage is not present between
Pin No. 3 of the 2-pin connector (A) and the
common terminal of the relay RY2.
The rated AC voltage is present at primary
side of low voltage transformer.
Only pattern at "a" is broken.
Pattern at "a" and "b" are broken.
make a visual inspection of the varistor.
Check for burned damage and exam-
ine the transformer with a tester for the
presence of layer short-circuit (check
the primary coil resistance which is ap-
proximately 212Ω ± 10% (for R-330AK/
AW), 563Ω ± 10% (for R-310AK)). If
any abnormal condition is detected,
replace the defective parts.
COMPONENT TEST
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
Low voltage transformer or secondary circuit defective.
Check and repair.
*Insert jumper wire J1 and solder.
*Insert the coil RCILF2003YAZZ between "c" and "d".
c
(J1)
2
a
d
b